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Talk:Amphetamine/Archive 8

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Latest comment: 1 year ago by Seppi333 in topic Re
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Evidence vs. usage

Latest comment: 6 years ago6 comments3 people in discussion

In my view, the most problematic part of the Amphetamine article is that it overemphasizes "amphetamine is used for" and underemphasizes "there is evidence of efficacy and safety of amphetamine for treatment of." Both evidence and usage ought to be described (of course, this is an encyclopedia, after all), but there should be balance. Some readers may infer from the language in the first sentence of the lede that it is reasonable to treat obesity with amphetamine, however I expect that most experts would consider the harms of using amphetamines for obesity to outweigh the benefits. The lede could cite a recent large, well-done study of prevalence of use.[1] It's not a meta-analysis, but is the best quality evidence we are likely to get.

Here's a draft sentence to consider for the lede: A 2018 study estimated that approximately 16 million people in the United States take amphetamines.[1]

Please note that the AACE/ACE guidelines for obesity treatment do not recommend amphetamine nor do they even recommend phentermine alone, and the guidelines caution prescribers about use of lorcaserin (which can be abused by using high doses). (The extended-release combo of phentermine/topiramate is on the AACE/ACE list of recommended drugs.) this reflects a consensus among experts about use of drugs with abuse potential for treatment of obesity. [2]

Sbelknap (talk) 22:09, 19 July 2018 (UTC)

Your concern is actually very similar to the one I mentioned at WT:MED. This article really only covers the safety/efficacy of amphetamine for ADHD, but it should cover this for ADHD, obesity, and narcolepsy. Unfortunately, there really aren't any meta-analyses that cover the efficacy of amphetamine for obesity (see this search). I would like to create the subsections on narcolepsy and obesity sometime in the near future though.
As for the lead, it wouldn't be a good idea to cover the safety/efficacy of its uses there since this article needs to give comparable coverage to each major subtopic in a very small amount of space (the limit for the size of the lead is 4 paragraphs for very large articles, per MOS:LEADLENGTH). I understand your desire to cover these things in the lead since many people come to articles and read leads, but I don't think that's entirely true for drug articles; e.g., whenever I go to an article as a reader and not an editor, I often ignore the lead altogether and go to the section pertaining to the topic that I'm interested in (and sometimes end up searching pubmed for relevant articles and expanding that section if I found it lacking). I can't imagine someone interested in knowing about its medical uses or pharmacology would stop at the 4 introductory paragraphs that summarize an entire article (especially one that's as massive as this one).
So, in a nutshell, I think the best approach would be to create the sections on obesity and narcolepsy. First, we need to get sources on amphetamine's efficacy for those uses though (i.e., meta-analyses for narcolepsy and medical reviews for obesity). I'll probably have time to look for sources on efficacy tonight once I've finished fleshing out the medical uses section of bupropion with the meta-analyses that I cited on bupropion's talk page. Once we have those sources, we can write those sections of this article.
As for the study you provided, my main concerns with using it to indicate the prevalence of prescription amphetamine use is that it doesn't quantify the use of amphetamine alone (i.e., it includes other prescription stimulants, like methylphenidate - which isn't a substituted amphetamine - and methamphetamine) and articles should ideally provide a global perspective. The global prevalence of both the licit (i.e., prescription) and illicit use of amphetamine-type stimulants is actually included in this article at present though: see the 1st table under Amphetamine#History, society, and culture. Seppi333 (Insert 2¢) 01:54, 20 July 2018 (UTC)
If you're willing to help me look for sources on efficacy, I would really appreciate your help! Seppi333 (Insert 2¢) 01:58, 20 July 2018 (UTC)

Obesity

I ran this search for recent reviews/practice guidelines/meta-analyses/systematic reviews that include amphetamine (in the title/abstract or mesh terms), obesity (in the title/abstract), and efficacy (in the title/abstract); came up with 7 sources and all of them were irrelevant. After repeating that search without the efficacy term, I found ~40. The only one that actually covered the efficacy of amphetamine for weight loss examined really old trials: PMID 25194183 doi:10.1016/j.bpg.2014.07.015). I don't think we'd be able to cover the efficacy in the obesity section. The only things we probably can cover are: (1) amphetamine is intended to be used as an adjunct therapy for a period of several weeks (per the prescribing information[3]) and (2) what non-Pubmed indexed practice guidelines say about it. I don't think it's worth covering the mechanism of action for this given the lack of evidence on efficacy. Seppi333 (Insert 2¢) 12:41, 20 July 2018 (UTC)

List of references relevant to this section:

Narcolepsy

I'm running into a similar problem with sources on efficacy for narcolepsy. There's a lot of reviews, but no pubmed indexed meta-analyses, practice guidelines, or systematic reviews that actually quantify its efficacy on the basis of some metric of symptom reduction. The main difference is that all of the reviews I've read in the past and skimmed through now all assert that it has treatment efficacy. I'll probably end up citing clinical practice guidelines for narcolepsy as well. These sources seem relevant: AASM guideline, AASM review, PMID 29759269, 26716917, 27549768, 28424564.

  • The AASM narcolepsy review states the following about the efficacy/use of amphetamine:
Selected excerpts from the AASM narcolepsy review

The traditional stimulants are considered mainstays for treatment of sleepiness associated with narcolepsy.21 The previous practice parameters published in 2001 by the AASM identified three level 2 studies and four level 5 studies that support the efficacy of traditional stimulants for treatment of sleepiness in narcolepsy.21 Our updated search from 1999 through October, 2006 identified no new studies of traditional stimulants for this indication that met inclusion criteria.

Our search identified one small case series with level 4 evidence involving five adolescents with Kleine-Levin syndrome treated with lithium carbonate.57 Although all patients experienced relapses while receiving lithium carbonate, the duration of hypersomnia episodes was shorter and there were no behavioral symptoms during episodes in which subjects were treated with lithium carbonate. Several small case reports indicate varying degrees of improvement or lack of improvement associated with treatment with a variety of medications including stimulants, anti-epileptic medications, antidepressants, and neuroleptics. A systematic review of Kleine-Levin syndrome patients by Arnulf, et al.58 reports that sleepiness decreased in 40% of 75 treated patients, using stimulants (primarily amphetamines). We identified no controlled studies that report results of treatment of recurrent hypersomnia with medications.

The AASM issued a statement in August, 2006 that addressed the “black box” warning (www.aasmnet.org). The statement reviewed that amphetamine preparations are effective agents for the treatment of sleepiness associated with narcolepsy, and should not be withheld from appropriate patients. They are generally used in patients with more severe sleepiness and when other medications have proven ineffective. The statement also indicated that physicians who prescribe amphetamines should be knowledgeable about the drugs and should carefully assess the risk-benefit ratio for each patient.

  • The AASM narcolepsy guideline states the following about amphetamine:
Selected excerpts from the AASM narcolepsy guideline

c. Amphetamine, methamphetamine, dextroamphetamine, and methylphenidate are effective for treatment of daytime sleepiness due to narcolepsy [4.1.1.1] (Guideline).
This recommendation is unchanged from the previous recommendation. These medications have a long history of effective use in clinical practice but have limited information available on benefit-to-risk ratio.4 This lack of information may reflect the limited sources of research funding for medications available in generic form rather than clinical utility of these medications

7. The following medications may be effective for treatment of daytime sleepiness in idiopathic hypersomnia (with and without long sleep time), recurrent hypersomnia, and hypersomnia due to a medical condition: amphetamine, methamphetamine, dextroamphetamine, methylphenidate, and modafinil [4.7, 4.8, 4.9] (Option)
The literature supporting the efficacy of these medications for other specific disorders such as narcolepsy have been reviewed. Where published evidence meeting search criteria is available for the use of any of these medications in the conditions listed, this has been provided in sections 4 and 5. This recommendation applies to those medications and conditions combinations for which published literature meeting search criteria is not available. Although there is no reason to suspect they will not improve alertness, individualized therapy and close follow-up to ensure efficacy and monitor for side effects is needed. The recommendations for these disorders are based on committee consensus.

iv. Of the stimulants used to treat hypersomnia of central origin, amphetamines, especially at high doses, are the most likely to result in the development of tolerance

1. Comparisons of traditional stimulants to newer somnolytic agents for hypersomnia due to narcolepsy.
Several large randomized, placebo-controlled studies indicate that modafinil and sodium oxybate are effective for treatment of hypersomnia associated with narcolepsy. The traditional stimulants (amphetamine, methamphetamine, dextroamphetamine, and methylphenidate) which are available in generic form and are less expensive, have a long history of use in clinical practice, but have limited high-level evidence from published studies. There is a need for randomized trials that compare the newer agents to the traditional stimulants to establish relative efficacy and safety of these agents to guide the clinician in choosing between them for individual patients.

Excerpts from PMID 29759269

Treatment of excessive daytime sleepiness
Stimulants still are the mainstay of the treatment of EDS.10,11 They enhance release and inhibit the reuptake of catecholamines and, to a lesser extent, serotonin in the central nervous system and the periphery. They are also weak inhibitors of monoamine oxidase. These include dextroamphetamine (5–60 mg/d; usually in 1–3 doses per day), ...
Long-acting agents (modafinil, armodafinil, dexamphetamine, methylphenidate, controlled release) are generally better tolerated than the short-acting ones. The quick and short-acting agents can be used to good effect when targeted at social events or difficult periods during the day. For this reason, combinations of stimulants may be tailored to the circumstances. Unfortunately, there are no studies assessing the advantages or disadvantages of combinations of stimulants.

Random aside: this review also asserted something I thought was interesting: the alerting effect of 6 cups of strong coffee is comparable with that of 5 mg of dexamphetamine.

I need to read through the last 2 reviews and check for additional practice guidelines for narcolepsy. I don't have any more time to do this right now, so I'll continue this later. Seppi333 (Insert 2¢) 00:11, 21 July 2018 (UTC)

Section reflist

References

  1. ^ a b Compton WM, Han B, Blanco C, Johnson K, Jones CM (April 2018). "Prevalence and Correlates of Prescription Stimulant Use, Misuse, Use Disorders, and Motivations for Misuse Among Adults in the United States". Am J Psychiatry. 175 (8): 741–755. doi:10.1176/appi.ajp.2018.17091048. PMC 6070393. PMID 29656665.
  2. ^ http://obesity.aace.com/files/obesity/guidelines/aace_guidelines_obesity_2016.pdf
  3. ^ "Evekeo Prescribing Information" (PDF). Arbor Pharmaceuticals LLC. September 2016. pp. 1–2. Retrieved 20 July 2018.

References tweaked

I removed pointers/links to sci-hub, as links to that site are blacklisted on en.wp and the WP:TLD keeps changing anyway, instead leaving DOI links. Obviously if you want to use sci-hub, that is enough info to find the articles there. DMacks (talk) 12:24, 17 October 2018 (UTC)

Updates

Latest comment: 4 years ago16 comments2 people in discussion

Monoaminergic/glutamatergic mechanisms

Things to add once I come across a second review covering all of these together - needs to provide context (citations for each are in the collapse tab below):

Seppi333 (Insert 2¢) 21:11, 6 December 2016 (UTC)

Pharmacodynamics diagram updates + new pharmacodynamics table

CAMKII signaling

Check for newer research involving:

Seppi333 (Insert 2¢) 02:00, 31 March 2016 (UTC) Updated 02:05, 27 April 2016 (UTC)

RhoA/ROCK signaling + DAT/EAAT3 internalization

  • Review[6] - covers effects of amph on RhoA signaling and RhoA-mediated EAAT3 internalization
  • Primary[7] - covers amph's cytosolic targets, effects of amph on RhoA signaling, ROCK activation, and ROCK-mediated DAT internalization (Note: this ref indicates that VGlut2 - the vesicular transport protein for glutamate which is located on glutamatergic synaptic vesicles - is expressed in mesolimbic TH-positive [i.e., dopamine] neurons; this implies that glutamatergic synaptic vesicles are present in mesolimbic DA neurons, which is a DA projection from midbrain nuclei [VTA+SNc] where EAAT3 is highly expressed according to PMID 25033183.)
Quote from ref[7] on VGlut2
Here we focused on the actions of AMPH on RhoA-dependent internalization of the DAT and explored how these effects on DAT trafficking might contribute to the acute behavioral response to the drug. However, recently we also demonstrated that a neuronal glutamate transporter, EAAT3, can be internalized in response to AMPH through a process that also appears to require Rho activation (17). This EAAT3 internalization in response to AMPH leads to a potentiation of glutamatergic synaptic responses in dopamine neurons and reveals a previously undescribed action of AMPH on glutamatergic signaling. A recent study has shown striking compartmentalization of glutamatergic and dopaminergic release sites within the processes of TH-positive neurons, where the two vesicular transporter types, VMAT2 and VGluT2, are segregated within distinct subcompartments (31). Intriguingly, we observe Rho activation broadly distributed within the processes of dopamine neurons. Taken together, these findings suggest a complex integration of dopaminergic and glutamatergic transmission within the mesoaccumbens pathway.
  • Primary[8] - covers amph's RhoA-mediated signaling cascade to DAT: transporter internalization via ROCKs (note to self: this ref covers PKC-mediated EAAT2 internalization; this is very likely the protein kinase that mediates TAAR1-mediated EAAT2 internalization by methamphetamine in astroglia - still have no clue why amphetamine doesn't do this)
  • Primary already cited in the article[9] - first paper to describe amphetamine-induced, RhoA-mediated internalization of EAAT3 in midbrain DA neurons

Seppi333 (Insert 2¢) 22:02, 6 November 2016 (UTC); Updated 17:53, 14 November 2016 (UTC)

Wikitable to add when updating pharmacodynamics diagram

Will probably definitely need to add something analogous to the following sentence in a note in order to explain how the columns in the table below are related:

  • Amphetamine interacts with its receptor protein target(s) (i.e., TAAR1 and a currently unidentified biomolecular target which initiates its CAMKIIα cascade), which triggers the activation of protein kinases. The activated kinases then phosphorylate their respective transporter(s), which in turn causes a conformational change in transporter protein, thereby altering its function and affecting dopaminergic/glutamatergic neurotransmission at dopaminergic synapses.
Effects of amphetamine on membrane transport proteins in dopamine neurons
Biological target
of amphetamine 		Secondary effector
protein kinase 		Phosphorylated
transporter 		Effect on transporter function Effect on neurotransmission Sources
Unidentified CAMKIIαTooltip Calcium/calmodulin-dependent protein kinase II alpha DATTooltip Dopamine transporter Reverse transport of dopamine Dopamine efflux into synaptic cleft [1][2][3]
TAAR1Tooltip Trace amine-associated receptor 1 ROCKTooltip Rho-associated protein kinase† DAT Transporter internalization Dopamine reuptake inhibition [10][7][8]
TAAR1 ROCK† EAAT3Tooltip Excitatory amino acid transporter 3 Transporter internalization Glutamate reuptake inhibition [10][7][8]
TAAR1 PKATooltip Protein kinase A DAT Transporter internalization Dopamine reuptake inhibition [11][12]
TAAR1 PKCTooltip Protein kinase C DAT Reverse transport of dopamine
Transporter internalization 		Dopamine efflux into synaptic cleft
Dopamine reuptake inhibition 		[2][11][12]
†Note: ROCK-mediated transporter internalization is transient due to the inactivation of RhoA (which activates ROCK) by PKA. [6][7][8]

The phosphorylation / inactivation of RhoA by PKA occurs roughly 10–15 minutes following neuronal exposure to amphetamine and more or less plateaus by 20–30 minutes post-exposure, based upon in vitro research. Seppi333 (Insert 2¢) 17:53, 14 November 2016 (UTC)

Amphetamine-induced ERK1/2-mediated phosphorylation of DAT on the Thr53 residue, which induces DA efflux, also appears to occur;[2][3] ERK1/2 is likely activated by the PKCβ isoform of PKC.[3]

Updated to reflect Fig 6,[10] but listing ROCK (2nd effector) instead of RhoA (2nd messenger) based upon this ref.[8]. Seppi333 (Insert 2¢) 21:51, 22 October 2019 (UTC)
Section reflist
  1. ^ a b Steinkellner T, Mus L, Eisenrauch B, Constantinescu A, Leo D, Konrad L, Rickhag M, Sørensen G, Efimova EV, Kong E, Willeit M, Sotnikova TD, Kudlacek O, Gether U, Freissmuth M, Pollak DD, Gainetdinov RR, Sitte HH (October 2014). "In vivo amphetamine action is contingent on αCaMKII". Neuropsychopharmacology. 39 (11): 2681–2693. doi:10.1038/npp.2014.124. PMC 4207348. PMID 24871545. Our findings demonstrate that amphetamine requires the presence of αCaMKII to elicit a full-fledged effect on DAT in vivo: αCaMKII does not only support acute amphetamine-induced dopamine efflux but is also important in shaping the chronic response to amphetamine.
  2. ^ a b c d Wang Q, Bubula N, Brown J, Wang Y, Kondev V, Vezina P (May 2016). "PKC phosphorylates residues in the N-terminal of the DA transporter to regulate amphetamine-induced DA efflux". Neurosci. Lett. 622: 78–82. doi:10.1016/j.neulet.2016.04.051. PMC 4870132. PMID 27113203. The DA transporter (DAT), a phosphoprotein, controls extracellular dopamine (DA) levels in the central nervous system through transport or reverse transport (efflux). Multiple lines of evidence support the claim that PKC significantly contributes to amphetamine-induced DA efflux. Other signaling pathways, involving CaMKII and ERK, have also been shown to regulate DAT mediated efflux. ... The results of in vitro experiments using a recombinant N-terminal peptide of DAT [11,17] indicate that PKC phosphorylates the S4, S7, and S13 residues, that the S7 and S13 residues are also phosphorylated by PKA and CaMKII respectively, and that the T53 residue is phosphorylated by ERK1/2 (Fig. 1). ... Together, these findings suggest that PKC is not the only protein kinase that regulates amphetamine-induced DA efflux and, importantly, that it may function in concert with others at multiple residues in the N-terminal of the DAT to fully regulate its function. Indeed, DA efflux is regulated by several kinases in addition to PKC, including CaMKII and ERK1/2 [5,6], and all are capable of regulating the DAT by phosphorylating residues in its N-terminal [11–15,17] ... As some but not all findings indicate that CaMKII contributes to acute amphetamine-induced DA efflux and behaviors [12-14; cf,20], it remains possible that the inhibitory effect of the DAT-S13A mutant on DA efflux observed in the present study might in part reflect an action of CaMKII ... In addition, in the present experiments, S/T-A mutation of the non-PKC residue S12 and the ERK1/2 residue T53 were each found to reduce amphetamine-induced DA efflux by approximately 25% as well. ... Indeed, the lack of inhibition of amphetamine-induced DA efflux observed in the present study with the DAT-S7A mutant may reflect the integration at S7 of antagonistic signaling by PKC and PKA pathways as this residue is phosphorylated by both kinases [17].
  3. ^ a b c d e Bermingham DP, Blakely RD (October 2016). "Kinase-dependent Regulation of Monoamine Neurotransmitter Transporters". Pharmacol. Rev. 68 (4): 888–953. doi:10.1124/pr.115.012260. PMC 5050440. PMID 27591044. The Amara laboratory recently provided evidence that AMPH triggered DAT endocytosis is clathrin-independent and requires the small GTPase Rho (Wheeler et al., 2015), which mediates another dynamin-dependent mode of endocytosis (Croise et al., 2014). These lines of evidence are consistent with a PKC-independent mode of DAT internalization by AMPH. ... Recent work from the Amara laboratory has implicated PKA signaling in the regulation of Rho-mediated DAT internalization, specifically in response to AMPH treatment (Wheeler et al., 2015). ...
    Whereas little support for CaMKII regulation of DA uptake exists, substantial evidence supports a role for the kinase in DAT-dependent DA efflux triggered by AMPH or DAT mutations. ... Importantly, AMPH treatment of DAT transfected cells produced a rise in intracellular Ca2+ that could be blocked by thapsigargin or cocaine, supporting a model whereby AMPH is first transported into cells where it can then produce release of endoplasmic reticulum Ca2+ stores. Subsequently, AMPH was shown to activate CaMKII in DAT transfected cells (Wei et al., 2007). ... As noted above, an important role for CaMKII activity in AMPH-evoked DA efflux has been defined through the use of organic and peptide CaMKII inhibitors, intracellular kinase perfusion and the use of CaMKII KO/knock-in mouse models. The question naturally arises as to whether this contribution arises from direct, CaMKII-mediated DAT phosphorylation. ... At present, information is lacking as to the site(s) that support CaMKII phosphorylation of DAT in vivo ... The current model for how CaMKII participates in AMPH-triggered DA efflux involves binding of the kinase to the transporter C terminus followed by phosphorylation of one or more Ser residues in the transporter N terminus. This phosphorylation is then thought to facilitate conformational changes that place the transporter in a "DA efflux-willing" conformation. ...
    Thus, Kantor et al. (2004) described enhancement of DA efflux by PC-12 cells that was dependent on external Ca2+ and is blocked by the voltage-gated Ca2+ channel (VGCC) inhibitors v-conotoxin and nifedipine. The reader will recall that evidence suggests that DAT-mediated DA efflux after AMPH treatment relies more on intracellular Ca2+ stores than extracellular Ca2+, ... Interestingly, AMPH also elicited a greater increase in Ca2+ elevations after repeated treatment, suggesting possible changes in expression/activity of Ca2+ channels as well. The actions of AMPH to elevate Ca2+ levels were blocked by desipramine, suggesting that AMPH-induced depolarization may be responsible for Ca2+ channel activation. Consistent with this idea, Cameron et al. (2015) recently reported an ability of AMPH to activate VGCCs via transporter-mediated depolarization. ...
    Based on work from Chen et al. (2013) that showed that PKCβ appears to function upstream of ERK1/2, which are strong candidates for targeting Thr53 (Gorentla et al., 2009), it is possible that PKCβ may act through ERK1/2 to increase Thr53 phosphorylation and therefore positively regulate DAT, whereas other PKC isoforms act to downregulate DAT activity, potentially through direct phosphorylation of the transporter or other interacting proteins. ... As an equivalent loss of AMPH evoked efflux capacity was observed for both Ala and Asp substitutions, the precise role of phosphorylation at Thr53 in AMPH-induced DA efflux remains to be established.
  4. ^ Cameron KN, Solis E, Ruchala I, De Felice LJ, Eltit JM (2015). "Amphetamine activates calcium channels through dopamine transporter-mediated depolarization". Cell Calcium. 58 (5): 457–66. doi:10.1016/j.ceca.2015.06.013. PMC 4631700. PMID 26162812. One example of interest is CaMKII, which has been well characterized as an effector of Ca2+ currents downstream of L-type Ca2+ channels [21,22]. Interestingly, DAT is a CaMKII substrate and phosphorylated DAT favors the reverse transport of dopamine [48,49], constituting a possible mechanism by which electrical activity and L-type Ca2+ channels may modulate DAT states and dopamine release. ... In summary, our results suggest that pharmacologically, S(+)AMPH is more potent than DA at activating hDAT-mediated depolarizing currents, leading to L-type Ca2+ channel activation, and the S(+)AMPH-induced current is more tightly coupled than DA to open L-type Ca2+ channels.
  5. ^ Ruchala I, Cabra V, Solis E, Glennon RA, De Felice LJ, Eltit JM (2014). "Electrical coupling between the human serotonin transporter and voltage-gated Ca(2+) channels". Cell Calcium. 56 (1): 25–33. doi:10.1016/j.ceca.2014.04.003. PMC 4052380. PMID 24854234. S(+)MDMA (ecstasy) and 5HT (serotonin) induce Ca2+ mobilization in cultured muscle cells expressing hSERT. ...
    The electrical coupling between hSERT and CaV1.3 takes place at physiological concentrations of 5HT.
    hSERT-mediated depolarization activates voltage-gated calcium channels.
  6. ^ a b Bjørn-Yoshimoto WE, Underhill SM (September 2016). "The importance of the excitatory amino acid transporter 3 (EAAT3)". Neurochem. Int. 98: 4–18. doi:10.1016/j.neuint.2016.05.007. PMC 4969196. PMID 27233497. Recently, it was reported that amphetamine decreases the surface expression of EAAT3 (Underhill et al., 2014). This was dependent on a C-terminal sequence, VNGGF, which has previously been identified as important in targeting the transporter to dendrites in hippocampal neurons (Cheng et al., 2002). This also overlaps with motifs important for internalization (YVNGGF) via interaction with the AP2 complex (D' Amico et al., 2010) and PDGF-stimulated increased surface expression (YVN) (Sheldon et al., 2006). The amphetamine-induced decrease in surface EAAT3 was mediated by RhoA (see figure 3). Amphetamine also increased both AMPAR and NMDAR-mediated evoked excitatory post-synaptic currents in substantia nigra pars compacta slices when stimulating glutamatergic inputs, and this was blocked by a VNGGF peptide in the recording pipette. These observations are consistent with the effects being mediated by increased local Glu concentrations due to decreased post-synaptic EAAT3, suggesting that EAAT3 regulation could be a mechanism involved in the learning and memory aspect of amphetamine addiction (Tzschentke and Schmidt, 2003). Interestingly, it was recently reported that the dopamine transporter follows the same RhoA dependent mechanism of amphetamine-induced endocytosis (Wheeler et al., 2015). This effect is time-dependent due to increased cAMP inactivating RhoA, which could suggest a similar regulation for EAAT3 trafficking. ...
    RhoA is a downstream target of intracellular amphetamine. Both mechanisms of RhoA activation lead to a rapid decrease the surface expression of EAAT3.
  7. ^ a b c d e Wheeler DS, Underhill SM, Stolz DB, Murdoch GH, Thiels E, Romero G, Amara SG (December 2015). "Amphetamine activates Rho GTPase signaling to mediate dopamine transporter internalization and acute behavioral effects of amphetamine". Proc. Natl. Acad. Sci. U.S.A. 112 (51): E7138–E7147. doi:10.1073/pnas.1511670112. PMC 4697400. PMID 26553986. These observations support the existence of an unanticipated intracellular target that mediates the effects of AMPH on RhoA and cAMP signaling and suggest new pathways to target to disrupt AMPH action. ... To further confirm the role of Rho activation on AMPH-mediated DAT internalization in primary neurons, we investigated a potential downstream effector of Rho activation. The Rho-associated coiled-coil containing kinase (ROCK) is activated by Rho GTPases and plays a critical role in actin cytoskeletal rearrangements. Coapplication of the ROCK inhibitor, Y27632, blocked the effects of AMPH pretreatment on dopamine uptake in primary midbrain cultures (Fig. 2F). These data further support a role for Rho activation in the mechanism of action of AMPH. ... Our data using a ROCK inhibitor to block the effects of AMPH pretreatment on dopamine uptake link ROCK activation to DAT internalization, complementing previous studies that suggest a role for ROCK in some aspects of AMPH's behavioral effects (29). ...
    The activation of intracellular signaling pathways by AMPH and the Rho-mediated internalization of DAT are also observed in nonneural cell lines transfected with DAT, which demonstrates that these effects do not require synaptic vesicles or endogenous dopamine. We also found that the presence of AMPH within the cytosol, and not the binding and transport through DAT, was essential for stimulating these signaling cascades ...
    The precise nature and the pharmacological properties of the cytoplasmic target(s) of AMPH remain to be established, but a trace amine-associated receptor, TAAR1, that is expressed in dopamine neurons and has a predominantly intracellular distribution is a potential candidate. As a Gs-coupled GPCR that responds to a variety of endogenous and exogenous amines and neurotransmitter metabolites, TAAR1 has been shown to be activated by AMPH and a variety of AMPH-like compounds and is likely responsible for the increases in cAMP generally observed following the application of AMPH to cells (32, 33). Whether TAAR1 also mediates the activation of the small GTPases, RhoA, and Rac1 remains to be established.
    Together, the studies reported here indicate that the effects of AMPH not only depend on the drug's well-established actions on uptake and efflux through the DAT, but also require the activation of multiple signaling pathways by acting on additional target(s) within the cell. Cytoplasmic cAMP appears to integrate both intracellular signals through GTPase activation and extracellular signals from GPCR-coupled pathways to shape response of a dopamine neuron to AMPH. Thus, modulation of the Rho activation/inactivation sequence provides a mechanism by which drugs and endogenous neurotransmitters can influence the response of dopamine neurons to AMPH.
  8. ^ a b c d e Saunders C, Galli A (December 2015). "Insights in how amphetamine ROCKs (Rho-associated containing kinase) membrane protein trafficking". Proc. Natl. Acad. Sci. U.S.A. 112 (51): 15538–15539. doi:10.1073/pnas.1520960112. PMC 4697384. PMID 26607447. In this elegant and thorough study (7), Amara and her collaborators identify multiple novel targets for intracellular AMPH. They demonstrate that cytoplasmic AMPH stimulates a secondary pathway of cAMP production, which leads to Rho inactivation by PKA-dependent phosphorylation. ... Furthermore, the authors involve the Rho-associated coiled-coil containing kinase (ROCK) in the AMPH actions, because ROCK inhibition blocks the effects of AMPH pretreatment on DA uptake. These data support previous studies, suggesting a role for ROCK in AMPH's behavioral effects. ... In this elegant and thorough study (7), Amara and her collaborators identify multiple novel targets for intracellular AMPH. They demonstrate that cytoplasmic AMPH stimulates a secondary pathway of cAMP production, which leads to Rho inactivation by PKA-dependent phosphorylation. The authors provide a mechanism whereby RhoA-dependent and PKA signaling interact to regulate the timing and magnitude of AMPH's effects on DAT internalization. The pivotal role of DAT trafficking in AMPH-induced behaviors was also tested in vivo. ... These results further support the idea that the direct activation of cytoplasmic signaling cascades by AMPH might contribute to the behavioral effects of acute AMPH exposure. ... It is noteworthy to point out that in addition to its effects on Rho-mediated transporter trafficking, AMPH elevates extracellular DA through other mechanisms, such as facilitating efflux and inhibiting the DAT.
  9. ^ Underhill SM, Wheeler DS, Li M, Watts SD, Ingram SL, Amara SG (July 2014). "Amphetamine modulates excitatory neurotransmission through endocytosis of the glutamate transporter EAAT3 in dopamine neurons". Neuron. 83 (2): 404–416. doi:10.1016/j.neuron.2014.05.043. PMC 4159050. PMID 25033183. AMPH also increases intracellular calcium (Gnegy et al., 2004) that is associated with calmodulin/CamKII activation (Wei et al., 2007) and modulation and trafficking of the DAT (Fog et al., 2006; Sakrikar et al., 2012). ... For example, AMPH increases extracellular glutamate in various brain regions including the striatum, VTA and NAc (Del Arco et al., 1999; Kim et al., 1981; Mora and Porras, 1993; Xue et al., 1996), but it has not been established whether this change can be explained by increased synaptic release or by reduced clearance of glutamate. ... DHK-sensitive, EAAT2 uptake was not altered by AMPH (Figure 1A). The remaining glutamate transport in these midbrain cultures is likely mediated by EAAT3 and this component was significantly decreased by AMPH
  10. ^ a b c Underhill SM, Hullihen PD, Chen J, Fenollar-Ferrer C, Rizzo MA, Ingram SL, Amara SG (August 2019). "Amphetamines signal through intracellular TAAR1 receptors coupled to Gα13 and GαS in discrete subcellular domains". Mol. Psychiatry. doi:10.1038/s41380-019-0469-2. PMID 31399635. Figure 6: Amphetamine signling through intracellular TAAR1 receptors {{cite journal}}: External link in |quote= (help)
  11. ^ a b Miller GM (January 2011). "The emerging role of trace amine-associated receptor 1 in the functional regulation of monoamine transporters and dopaminergic activity". J. Neurochem. 116 (2): 164–176. doi:10.1111/j.1471-4159.2010.07109.x. PMC 3005101. PMID 21073468.
  12. ^ a b Grandy DK, Miller GM, Li JX (February 2016). ""TAARgeting Addiction"-The Alamo Bears Witness to Another Revolution: An Overview of the Plenary Symposium of the 2015 Behavior, Biology and Chemistry Conference". Drug Alcohol Depend. 159: 9–16. doi:10.1016/j.drugalcdep.2015.11.014. PMC 4724540. PMID 26644139.
Tentative changes to diagram
Pharmacodynamics of amphetamine in a dopamine neuron
 
via AADC
 
Amphetamine enters the presynaptic neuron across the neuronal membrane or through DAT.[1] Once inside, it binds to TAAR1 or enters synaptic vesicles through VMAT2.[1][2] When amphetamine enters synaptic vesicles through VMAT2, it collapses the vesicular pH gradient, which in turn causes dopamine to be released into the cytosol (light tan-colored area) through VMAT2.[2][3] When amphetamine binds to TAAR1, it reduces the firing rate of the dopamine neuron via G protein-coupled inwardly rectifying potassium channels (GIRKs) and activates protein kinase A (PKA) and protein kinase C (PKC), which subsequently phosphorylate DAT.[1][4][5] PKA phosphorylation causes DAT to withdraw into the presynaptic neuron (internalize) and cease transport.[1] PKC-phosphorylated DAT may either operate in reverse or, like PKA-phosphorylated DAT, internalize and cease transport.[1] Amphetamine is also known to increase intracellular calcium, an effect which is associated with DAT phosphorylation through a CAMKIIα-dependent pathway, in turn producing dopamine efflux.[6][7]

Things to add to or change in the {{Amphetamine pharmacodynamics}} diagram:

  • add some sort of geometric figure w/ "Unidentified intracellular target(s)" written in the center as text Just going to wait for the CAMKII-alpha cascade to be fully elucidated, but I have a gut feeling it's also TAAR1-activated.
  • add glutamatergic synaptic vesicles w/ VGlut2
  • add some glutamate molecules to the figure
  • add EAAT3 on the plasma membrane
  • draw pathway from amphetamine through TAAR1, through RhoA, then through ROCK, then to both DAT and EAAT3 - indicate transporter internalization occurs†
  • draw pathway from amphetamine through "Unidentified intracellular target(s)", through CAMKIIα, then to DAT, indicate DA efflux occurs‡
  • change "DAT internalization" to "PKA- or ROCK-mediated DAT internalization"
  • change "Dopamine release" to "PKC- or CAMKIIα- mediated dopamine efflux"
  • consider removing phenethylamine + trace amine signaling from the figure if it becomes too complicated as a result of these changes

† need to wait for a ref to be published which explicitly states that DAT and EAAT3 are phosphorylated by a ROCK or a different RhoA-activated protein kinase
‡ need to find a ref to verify that CAMKII signaling is triggered by amphetamine interacting with an intracellular target before doing this - stated in this review: "Importantly, AMPH treatment of DAT transfected cells produced a rise in intracellular Ca2+ that could be blocked by thapsigargin or cocaine, supporting a model whereby AMPH is first transported into cells where it can then produce release of endoplasmic reticulum Ca2+ stores. Subsequently, AMPH was shown to activate CaMKII in DAT transfected cells (Wei et al., 2007)."
Seppi333 (Insert 2¢) 17:53, 14 November 2016 (UTC)

Diagram reflist

[1][2][3][4][5][6][7]

  1. ^ a b c d e f Miller GM (January 2011). "The emerging role of trace amine-associated receptor 1 in the functional regulation of monoamine transporters and dopaminergic activity". J. Neurochem. 116 (2): 164–176. doi:10.1111/j.1471-4159.2010.07109.x. PMC 3005101. PMID 21073468. Cite error: The named reference "Miller" was defined multiple times with different content (see the help page).
  2. ^ a b c Eiden LE, Weihe E (January 2011). "VMAT2: a dynamic regulator of brain monoaminergic neuronal function interacting with drugs of abuse". Ann. N. Y. Acad. Sci. 1216 (1): 86–98. Bibcode:2011NYASA1216...86E. doi:10.1111/j.1749-6632.2010.05906.x. PMC 4183197. PMID 21272013. VMAT2 is the CNS vesicular transporter for not only the biogenic amines DA, NE, EPI, 5-HT, and HIS, but likely also for the trace amines TYR, PEA, and thyronamine (THYR) ... [Trace aminergic] neurons in mammalian CNS would be identifiable as neurons expressing VMAT2 for storage, and the biosynthetic enzyme aromatic amino acid decarboxylase (AADC). ... AMPH release of DA from synapses requires both an action at VMAT2 to release DA to the cytoplasm and a concerted release of DA from the cytoplasm via "reverse transport" through DAT. Cite error: The named reference "E Weihe" was defined multiple times with different content (see the help page).
  3. ^ a b Sulzer D, Cragg SJ, Rice ME (August 2016). "Striatal dopamine neurotransmission: regulation of release and uptake". Basal Ganglia. 6 (3): 123–148. doi:10.1016/j.baga.2016.02.001. PMC 4850498. PMID 27141430. Despite the challenges in determining synaptic vesicle pH, the proton gradient across the vesicle membrane is of fundamental importance for its function. Exposure of isolated catecholamine vesicles to protonophores collapses the pH gradient and rapidly redistributes transmitter from inside to outside the vesicle. ... Amphetamine and its derivatives like methamphetamine are weak base compounds that are the only widely used class of drugs known to elicit transmitter release by a non-exocytic mechanism. As substrates for both DAT and VMAT, amphetamines can be taken up to the cytosol and then sequestered in vesicles, where they act to collapse the vesicular pH gradient.
  4. ^ a b Ledonne A, Berretta N, Davoli A, Rizzo GR, Bernardi G, Mercuri NB (July 2011). "Electrophysiological effects of trace amines on mesencephalic dopaminergic neurons". Front. Syst. Neurosci. 5: 56. doi:10.3389/fnsys.2011.00056. PMC 3131148. PMID 21772817. Three important new aspects of TAs action have recently emerged: (a) inhibition of firing due to increased release of dopamine; (b) reduction of D2 and GABAB receptor-mediated inhibitory responses (excitatory effects due to disinhibition); and (c) a direct TA1 receptor-mediated activation of GIRK channels which produce cell membrane hyperpolarization. Cite error: The named reference "GIRK" was defined multiple times with different content (see the help page).
  5. ^ a b "TAAR1". GenAtlas. University of Paris. 28 January 2012. Retrieved 29 May 2014.  • tonically activates inwardly rectifying K(+) channels, which reduces the basal firing frequency of dopamine (DA) neurons of the ventral tegmental area (VTA) Cite error: The named reference "Genatlas TAAR1" was defined multiple times with different content (see the help page).
  6. ^ a b Underhill SM, Wheeler DS, Li M, Watts SD, Ingram SL, Amara SG (July 2014). "Amphetamine modulates excitatory neurotransmission through endocytosis of the glutamate transporter EAAT3 in dopamine neurons". Neuron. 83 (2): 404–416. doi:10.1016/j.neuron.2014.05.043. PMC 4159050. PMID 25033183. AMPH also increases intracellular calcium (Gnegy et al., 2004) that is associated with calmodulin/CamKII activation (Wei et al., 2007) and modulation and trafficking of the DAT (Fog et al., 2006; Sakrikar et al., 2012). ... For example, AMPH increases extracellular glutamate in various brain regions including the striatum, VTA and NAc (Del Arco et al., 1999; Kim et al., 1981; Mora and Porras, 1993; Xue et al., 1996), but it has not been established whether this change can be explained by increased synaptic release or by reduced clearance of glutamate. ... DHK-sensitive, EAAT2 uptake was not altered by AMPH (Figure 1A). The remaining glutamate transport in these midbrain cultures is likely mediated by EAAT3 and this component was significantly decreased by AMPH
  7. ^ a b Vaughan RA, Foster JD (September 2013). "Mechanisms of dopamine transporter regulation in normal and disease states". Trends Pharmacol. Sci. 34 (9): 489–496. doi:10.1016/j.tips.2013.07.005. PMC 3831354. PMID 23968642. AMPH and METH also stimulate DA efflux, which is thought to be a crucial element in their addictive properties [80], although the mechanisms do not appear to be identical for each drug [81]. These processes are PKCβ– and CaMK–dependent [72, 82], and PKCβ knock-out mice display decreased AMPH-induced efflux that correlates with reduced AMPH-induced locomotion [72].

Addiction

  • Really interesting papers based upon the abstracts; probably useful information worth adding to relevant articles: PMID 31749652, 29511807, 31071288, 31698743, 31680830
  • Need to indicate that the current evidence base for physical exercise as a treatment for amph/meth addiction supports its use even as a monotherapy sans behavioral therapy and is more effective than CBT in certain outcome domains. Also a stronger evidence base for exercise as an addiction prophylactic PMID 31344831, 29266758, 29430384, 29338767
  • PMID 31695630 - interesting cognitive control-based strategy (maximal utilization of working memory) to interfere with craving/incentive salience for drug use
  • May 2017 meta-analysis[1]

References

  1. ^ Ashok AH, Mizuno Y, Volkow ND, Howes OD (May 2017). "Association of Stimulant Use With Dopaminergic Alterations in Users of Cocaine, Amphetamine, or Methamphetamine: A Systematic Review and Meta-analysis". JAMA Psychiatry. 74 (5): 511–519. doi:10.1001/jamapsychiatry.2017.0135. PMC 5419581. PMID 28297025.

Menstrual cycle

Need more evidence on this before covering sex-dependent differences in drug response. Seppi333 (Insert 2¢) 17:39, 25 December 2019 (UTC)

References

  1. ^ Van Voorhees EE, Mitchell JT, McClernon FJ, Beckham JC, Kollins SH (May 2012). "Sex, ADHD symptoms, and smoking outcomes: an integrative model". Med. Hypotheses. 78 (5): 585–593. doi:10.1016/j.mehy.2012.01.034. PMC 3321070. PMID 22341778. research with cocaine and amphetamine in humans has found that the women report greater positive subjective effects of both substances during the follicular than the luteal phase of the menstrual cycle [129]. Moreover, men report greater positive subjective effects of stimulants compared to women who are in the luteal phase, though these gender differences disappear during the follicular phase [104, 130, 131]. Some [130, 131] but not all [132] research has found plasma or salivary estrogen levels to be associated positively with subjective response to amphetamine, and one study found that exogenously administered estrogen enhanced the discriminative stimulus effects of low doses of amphetamine [106].

Effects

  • [1] - may be worth covering some content from this chapter:
    1. acute effect on glucocorticoids via HPA axis   Done
    2. amphetamine increases orgasm pleasure, libido increases more in women than in men, high/supratherapeutic doses significantly promote libido   Pending

Seppi333 (Insert 2¢) 08:28, 4 December 2015 (UTC)

Updated 06:54, 9 October 2016 (UTC)
Updated 17:39, 25 December 2019 (UTC)

References

  1. ^ Gunne LM (2013). "Effects of Amphetamines in Humans". Drug Addiction II: Amphetamine, Psychotogen, and Marihuana Dependence. Berlin, Germany; Heidelberg, Germany: Springer. pp. 247–260. ISBN 9783642667091. Retrieved 4 December 2015.

Completed updates

Resolved threads

Older addiction content

References

  1. ^ Carroll ME, Smethells JR (February 2016). "Sex Differences in Behavioral Dyscontrol: Role in Drug Addiction and Novel Treatments". Front. Psychiatry. 6: 175. doi:10.3389/fpsyt.2015.00175. PMC 4745113. PMID 26903885. Environmental Enrichment ...
    In humans, non-drug rewards delivered in a contingency management (CM) format successfully reduced drug dependence [for a review see Ref. (188)]. In general, CM programs promote drug abstinence through a combination of positive reinforcement for drug-free urine samples. For instance, voucher-based reinforcement therapy in which medication compliance, therapy session attendance, and negative drug screenings reinforced with vouchers to local business (e.g., movie theater, restaurants, etc.) directly reinforces drug abstinence, provides competing reinforcers, enriches the environment, and it is a robust treatment across a broad range of abused drugs (189). ...
    Physical Exercise
    There is accelerating evidence that physical exercise is a useful treatment for preventing and reducing drug addiction [see reviews in Ref. (28, 178, 190, 191)]. In some individuals, exercise has its own rewarding effects, and a behavioral economic interaction may occur, such that physical and social rewards of exercise can substitute for the rewarding effects of drug abuse. ... The value of this form of treatment for drug addiction in laboratory animals and humans is that exercise, if it can substitute for the rewarding effects of drugs, could be self-maintained over an extended period of time. Work to date in laboratory animals [for review, see Ref. (191)] and humans [for review, see Ref. (178)] regarding exercise as a treatment for drug addiction supports this hypothesis. ... However, a RTC study was recently reported by Rawson et al. (226), whereby they used 8 weeks of exercise as a post-residential treatment for METH addiction, showed a significant reduction in use (confirmed by urine screens) in participants who had been using meth 18 days or less a month. ... Animal and human research on physical exercise as a treatment for stimulant addiction indicates that this is one of the most promising treatments on the horizon. [emphasis added]    {{cite journal}}: CS1 maint: unflagged free DOI (link)

Pharmaceuticals + related article text

  Resolved
  • [1] - also need to update table entry   Done

Seppi333 (Insert 2¢) 17:33, 16 November 2015 (UTC)

References

  1. ^ "Dyanavel XR Prescribing Information" (PDF). Tris Pharmaceuticals. October 2015. pp. 1–16. Retrieved 23 November 2015. DYANAVEL XR contains d-amphetamine and l-amphetamine in a ratio of 3.2 to 1 ... The most common (≥2% in the DYANAVEL XR group and greater than placebo) adverse reactions reported in the Phase 3 controlled study conducted in 108 patients with ADHD (aged 6–12 years) were: epistaxis, allergic rhinitis and upper abdominal pain. ...
    DOSAGE FORMS AND STRENGTHS
    Extended-release oral suspension contains 2.5 mg amphetamine base per mL.

Abuse contraindication

  Resolved
  • Add note on abuse history and prescriptions[1]   Done

Seppi333 (Insert 2¢) 21:21, 9 December 2015 (UTC)

References

  1. ^ Heal DJ, Smith SL, Gosden J, Nutt DJ (June 2013). "Amphetamine, past and present – a pharmacological and clinical perspective". J. Psychopharmacol. 27 (6): 479–496. doi:10.1177/0269881113482532. PMC 3666194. PMID 23539642. In reality, there is little abuse of these drugs by patients with ADHD (Merkel and Kuchibhatla, 2009), and in most cases the challenge for the prescribing doctor is to keep the patients taking their medication rather than limiting its use. Many teenage patients stop using despite the drugs having clear benefits for their school performance; they cite reasons such as feeling too controlled, wanting empowerment from medication, etc. For these reasons, observations of dependence and abuse of prescription d-amphetamine are rare in clinical practice, and this stimulant can even be prescribed to people with a history of drug abuse provided certain controls, such as daily pick-ups of prescriptions, are put in place (Jasinski and Krishnan, 2009b).{{cite journal}}: CS1 maint: multiple names: authors list (link)

another ergogenic effect

  Resolved
  • greater power output without any change in perceived exertion[1]   Added
  • neurophysiological mechanism is mediated by CNS dopamine, which allows the body to increase power output without affecting perceived exertion, presumably by raising the core temperature limit.[2]   Added

Seppi333 (Insert 2¢) 08:18, 9 March 2016 (UTC)

References

  1. ^ Rattray B, Argus C, Martin K, Northey J, Driller M (March 2015). "Is it time to turn our attention toward central mechanisms for post-exertional recovery strategies and performance?". Front. Physiol. 6: 79. doi:10.3389/fphys.2015.00079. PMC 4362407. PMID 25852568. Aside from accounting for the reduced performance of mentally fatigued participants, this model rationalizes the reduced RPE and hence improved cycling time trial performance of athletes using a glucose mouthwash (Chambers et al., 2009) and the greater power output during a RPE matched cycling time trial following amphetamine ingestion (Swart, 2009). ... Dopamine stimulating drugs are known to enhance aspects of exercise performance (Roelands et al., 2008){{cite journal}}: CS1 maint: unflagged free DOI (link)
  2. ^ Roelands B, De Pauw K, Meeusen R (June 2015). "Neurophysiological effects of exercise in the heat". Scand. J. Med. Sci. Sports. 25 Suppl 1: 65–78. doi:10.1111/sms.12350. PMID 25943657. Physical fatigue has classically been attributed to peripheral factors within the muscle (Fitts, 1996), the depletion of muscle glycogen (Bergstrom & Hultman, 1967) or increased cardiovascular, metabolic, and thermoregulatory strain (Abbiss & Laursen, 2005; Meeusen et al., 2006b). In recent decennia however, it became clear that the central nervous system plays an important role in the onset of fatigue during prolonged exercise (Klass et al., 2008), certainly when ambient temperature is increased  ... 5-HT, DA, and NA have all been implicated in the control of thermoregulation and are thought to mediate thermoregulatory responses, certainly since their neurons innervate the hypothalamus (Roelands & Meeusen, 2010). ... Strikingly, both the ratings of perceived exertion and the thermal sensation were not different to the placebo trial. This indicates that subjects did not feel they were producing more power and consequently more heat. ... Taken together, these data indicate strong ergogenic effects of an increased DA concentration in the brain, without any change in the perception of effort. ... The combined effects of DA and NA on performance in the heat were studied by our research group on a number of occasions. ... the administration of bupropion (DA/NA reuptake inhibitor) significantly improved performance. Coinciding with this ergogenic effect, the authors observed core temperatures that were much higher compared with the placebo situation. Interestingly, this occurred without any change in the subjective feelings of thermal sensation or perceived exertion. Similar to the methylphenidate study (Roelands et al., 2008b), bupropion may dampen or override inhibitory signals arising from the central nervous system to cease exercise because of hyperthermia, and enable an individual to continue maintaining a high power output

Ntox

  Resolved
  • Review - covers relationship between amphetamine-induced hyperthermia and neurotoxicity[1]   Added

Seppi333 (Insert 2¢) 22:02, 6 November 2016 (UTC)

References

  1. ^ Bowyer JF, Hanig JP (November 2014). "Amphetamine- and methamphetamine-induced hyperthermia: Implications of the effects produced in brain vasculature and peripheral organs to forebrain neurotoxicity". Temperature (Austin). 1 (3): 172–182. doi:10.4161/23328940.2014.982049. PMC 5008711. PMID 27626044. Hyperthermia alone does not produce amphetamine-like neurotoxicity but AMPH and METH exposures that do not produce hyperthermia (≥40°C) are minimally neurotoxic. Hyperthermia likely enhances AMPH and METH neurotoxicity directly through disruption of protein function, ion channels and enhanced ROS production. Forebrain neurotoxicity can also be indirectly influenced through the effects of AMPH- and METH- induced hyperthermia on vasculature. The hyperthermia and the hypertension produced by high doses amphetamines are a primary cause of transient breakdowns in the blood-brain barrier (BBB) resulting in concomitant regional neurodegeneration and neuroinflammation in laboratory animals. ... In animal models that evaluate the neurotoxicity of AMPH and METH, it is quite clear that hyperthermia is one of the essential components necessary for the production of histological signs of dopamine terminal damage and neurodegeneration in cortex, striatum, thalamus and hippocampus.

Carbonic anhydrases

  Resolved
Brain carbonic anhydrase activation
Human carbonic anhydrase
activation potency
Enzyme KA (nMTooltip nanomolar) Sources
hCA4 94 [1]
hCA5A 810 [1][2]
hCA5B 2560 [1]
hCA7 910 [1][2]
hCA12 640 [1]
hCA13 24100 [1]
hCA14 9150 [1]

@Boghog: Can you help me create CA5A/carbonic anhydrase 5A and CA13/carbonic anhydrase 13? Those are the only carbonic anhydrase genes/proteins that WP is missing articles on (according to list of human protein-coding genes 1). Seppi333 (Insert 2¢) 22:19, 31 December 2019 (UTC)


Given that the following passage very closely paraphrases (w/ entire clauses repeated verbatem; they even cite my molecular neuropharmacology textbook... lol) a late-2017 amphetamine revision, I don't really care about the length of the quote in the citation to the 1st paper. I.e., this entire paragraph: Amines 5–9 are strong central nervous system (CNS) stimulants and were originally used as drugs, for the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, obesity, nasal congestion, and depression35–37. They interfere with the catecholamine neurotransmitters norepinephrine and dopamine metabolism, by the activation of a trace amine receptor31, which leads to an increase of monoamine and excitatory neurotransmitter activity in the brain, leading to emotional and cognitive effects such as euphoria, change in desire for sex, increased wakefulness, accompanied by improved cognitive control38–40. However, drug addiction is a serious risk with the recreational use of these substances, with high doses leading to psychosis, such as delusions and paranoia, as well as many other serious side effects41.[1]

  • Need to create a wikitable to add activation data to the article in the very near future.[1]
  • Other refs on CA activation: IUPHAR/BPS entry and a primary source covering amph-induced activation of 2 hCA isoforms[3]
Regarding glaucoma-implicated CA isoenzymes (CA2, CA4, and CA12):[4]

References

  1. ^ a b c d e f g h i Angeli A, Vaiano F, Mari F, Bertol E, Supuran CT (December 2017). "Psychoactive substances belonging to the amphetamine class potently activate brain carbonic anhydrase isoforms VA, VB, VII, and XII". Journal of Enzyme Inhibition and Medicinal Chemistry. 32 (1): 1253–1259. doi:10.1080/14756366.2017.1375485. PMC 6009978. PMID 28936885. Here, we report the first such study, showing that amphetamine, methamphetamine, phentermine, mephentermine, and chlorphenteramine, potently activate several CA isoforms, some of which are highly abundant in the brain, where they play important functions connected to cognition and memory, among others26,27. ... We investigated psychotropic amines based on the phenethylamine scaffold, such as amphetamine 5, methamphetamine 6, phentermine 7, mephentermine 8, and the structurally diverse chlorphenteramine 9, for their activating effects on 11 CA isoforms of human origin ... The widespread hCA I and II, the secreted hCA VI, as well as the cytosolic hCA XIII and membrane-bound hCA IX and XIV were poorly activated by these amines, whereas the extracellular hCA IV, the mitochondrial enzymes hCA VA/VB, the cytosolic hCA VII, and the transmembrane isoform hCA XII were potently activated. Some of these enzymes (hCA VII, VA, VB, XII) are abundant in the brain, raising the possibility that some of the cognitive effects of such psychoactive substances might be related to the activation of these enzymes. ... CAAs started to be considered only recently for possible pharmacologic applications in memory/cognition therapy27. This work may bring new lights on the intricate relationship between CA activation by this type of compounds and the multitude of pharmacologic actions that they can elicit.
    Table 1: CA activation of isoforms hCA I, II, IV, VII, and XIII [5: amphetamine]
    Table 2: CA activation of isoforms hCA VA, VB, VI, IX, XII, and XIV [5: amphetamine]     {{cite journal}}: External link in |quote= (help)
  2. ^ a b "Amphetamine: Biological activity". IUPHAR/BPS Guide to Pharmacology. International Union of Basic and Clinical Pharmacology. Retrieved 31 December 2019.
  3. ^ Tanini D, Capperucci A, Supuran CT, Angeli A (June 2019). "Sulfur, selenium and tellurium containing amines act as effective carbonic anhydrase activators". Bioorganic Chemistry. 87: 516–522. doi:10.1016/j.bioorg.2019.03.062. PMID 30928874.
  4. ^ Scozzafava A, Supuran CT (2014). "Glaucoma and the applications of carbonic anhydrase inhibitors". Sub-cellular Biochemistry. 75: 349–359. doi:10.1007/978-94-007-7359-2_17. PMID 24146387. Systemic inhibitors are useful in reducing elevated IOP characteristic of many glaucoma forms, as they represent the most efficient physiological treatment of glaucoma. Indeed by inhibiting the ciliary process enzymes (the sulfonamide susceptible isozymes CA II, CA IV and CA XII [5, 12, 17, 20]), a reduced rate of bicarbonate and aqueous humor secretion is achieved, which leads to a 25–30 % decrease of IOP [5, 17]. ... Some of these compounds showed effective in vitro inhibition of the target isoforms involved in glaucoma (in the low nanomolar range) i.e., hCA II, IV and XII, and the X-ray crystal structure of some of them bound to the dominant isoform hCA II also revealed factors associated with this marked inhibitory activity

Re

Latest comment: 1 year ago14 comments6 people in discussion

@Doc James and Casliber: Would like your feedback on Amphetamine#Pharmacomicrobiomics; pinging you two since you recently took an interest in this article. Only the second paragraph is technically "on topic" and within the article's scope, but the 2nd paragraph almost seems like trivia without a contextual understanding, which is what the first paragraph provides: it states the types of clinically significant drug-microbiota interactions. Really just looking for general feedback, but also wondering whether you think this particular statement from the 1st paragraph is worth keeping or cutting: The nascent and active field of research on drug-microbe interactions – known as pharmacomicrobiomics – lies at the intersection of systems microbiology, genomics, systems pharmacology, and personalized medicine.

@AmericanLemming: If you could proofread/copyedit this section like you did with the other technical ones during the FAC review, I'd greatly appreciate it.   I did my best to make it accessible, but I think you might be a better judge of what is/isn't understandable to a layperson than me for this topic. Seppi333 (Insert 2¢) 16:37, 5 August 2019 (UTC)

I agree that the first paragraph is too off-topic to include. I'd remove it. Cas Liber (talk · contribs) 20:34, 5 August 2019 (UTC)
I also agree with removing that paragraph due to it being off topic. Doc James (talk · contribs · email) 04:04, 7 August 2019 (UTC)

Initial comments

1. I agree with CasLiber that the first paragraph is a bit off-topic; the information there probably fits better in the main pharmacomicrobiomics article.
2. Also, it would be helpful to briefly explain the significance/implications of this study; for example, do the authors think that differences in the microbiome between individuals might explain some of the differences in how they respond to amphetamine?
3. I noticed that the link for tyramine oxidase redirects to the article on monoamine oxidase; is this bacterial enzyme analogous to human monoamine oxidase?

That's all for today. AmericanLemming (talk) 01:05, 7 August 2019 (UTC)

Re 1&2: Excluding the statements in the note and the first sentence about microbial and human genomes, everything in the first paragraph is mentioned in that study; the clinical significance of the finding is also mentioned in the paper, but I figured that since it's a primary source, I probably shouldn't be using it to cite a clinical claim. In a nutshell, the clinical significance is that E. coli can affect amphetamine's pharmacokinetics (its oral bioavailability and its metabolism) and variations in gastrointestinal E. coli colonization/concentration between individuals explains some of the inter-individual variation in amphetamine's clinical response (very high prevalence of E. coli in the gut → reduced clinical efficacy relative to people with normal [low] amounts of E. coli in the gut).[1] It goes on to discuss the use of the findings in redesigning the drug (see the quote below or read the end of the paper here: sci-hub.tw/10.1002/jcb.28396); however, I don't think the authors knew that amphetamine's prodrug (lisdexamfetamine) isn't converted into dextroamphetamine until it's absorbed into human blood plasma, which is (normally) sterile. I don't think it's likely that lisdexamfetamine would be metabolized by E. coli's tyramine oxidase due to the sizable difference in the chemical structure, but I may be wrong. @Doc James: do you think I should just cite the paper for the clinical statements?
Re 3: the tyramine oxidase they're referring to is the tyramine oxidase encoded by E. coli's tynA gene (this isn't mentioned in the paper, but they refer readers to expasy.org, which after navigating through the cross-links, one can find that tynA is listed as the encoding gene for E. coli's tyramine oxidase; also, the tyramine oxidase for one of the E. coli strains (i.e., MS 116‐1) that were mentioned in the paper (strains ATCC 8739, HS, MS 116‐1, MS 146‐1, MS 175‐1) on NCBI Protein is listed as being encoded by tynA). The correct article on this would be primary amine oxidase (per the NCBI Protein link, [1], and the UniProt entry for tynA in E. coli) since that's the name of the protein that tynA encodes and the fact that we normally use protein names as article titles.
Tangential point: Based upon the reaction that tyramine oxidase catalyzes (i.e., RCH2NH2 + H2O + O2   RCHO + NH3 + H2O2) and more specifically the fact that tynA metabolizes phenethylamine into phenylacetaldehyde and tyramine (4-hydroxyphenethylamine) into 4-hydroxyphenylacetaldehyde (I created this article today due to the number of red backlinks; the metabolic pathway I'm talking about here is now covered in that article), E. coli would seem to metabolize amphetamine into alpha-methylphenylacetaldehyde (which is probably further metabolized by E. coli's feaB enzyme into a methylated derivative of phenylacetate, based upon the metabolic fate of phenylacetaldehye and 4-hydroxyphenylacetaldehyde in E. coli - this pathway is covered in the UniProt link); that compound isn't naturally produced by any human enzymes. I obviously can't state any of this in the article since I can't (yet) cite a paper that explicitly covers it. Seppi333 (Insert 2¢) 11:31, 7 August 2019 (UTC)
Edit: I fixed the tyramine oxidase link in the article and mentioned tyramine oxidase/tynA in primary amine oxidase. The tyramine oxidase redirect is probably correctly targeted since I'm fairly certain that synonym maps either to the human MAOA gene or both human MAO genes. Seppi333 (Insert 2¢) 05:16, 8 August 2019 (UTC)
Is this clinically important. Doc James (talk · contribs · email) 13:55, 8 August 2019 (UTC)
Yes, and this information can be used clinically in any doctors' office that can test for microbial concentrations of specific strains of bacteria (which admittedly is very few at the moment, as it would require employing the same molecular biology techniques as required for diagnosing small intestinal bacterial overgrowth - i.e., gut fluid aspiration and a microbiological culture). Seppi333 (Insert 2¢) 03:58, 10 August 2019 (UTC)

References

  1. ^ Kumar K, Dhoke GV, Sharma AK, Jaiswal SK, Sharma VK (January 2019). "Mechanistic elucidation of amphetamine metabolism by tyramine oxidase from human gut microbiota using molecular dynamics simulations". Journal of Cellular Biochemistry. 120 (7): 11206–11215. doi:10.1002/jcb.28396. PMID 30701587. Numerous microorganisms reside with the human host in a symbiotic relationship and play an important role in the host metabolic processes and health.1,2 Several studies in the recent past have reported that there are compositional differences in the human microbiome due to factors such as geographical location, diet, age, and genetic variations.3 Particularly in the case of the human gut, which harbors a large diversity of bacterial species, the differences in microbial composition can significantly alter the metabolic activity in the gut lumen.4 The differential metabolic activity due to the differences in gut microbial species has been recently linked with various metabolic disorders and diseases.5-12 In addition to the impact of gut microbial diversity or dysbiosis in various human diseases, there is an increasing amount of evidence which shows that the gut microbes can affect the bioavailability and efficacy of various orally administrated drug molecules through promiscuous enzymatic metabolism.13,14 ... The present study on the atomistic details of amphetamine binding and binding affinity to the tyramine oxidase along with the comparison with two natural substrates of this enzyme namely tyramine and phenylalanine provides strong evidence for the promiscuity‐based metabolism of amphetamine by the tyramine oxidase enzyme of E. coli. The obtained results will be crucial in designing a surrogate molecule for amphetamine that can help either in improving the efficacy and bioavailability of the amphetamine drug via competitive inhibition or in redesigning the drug for better pharmacological effects. This study will also have useful clinical implications in reducing the gut microbiota caused variation in the drug response among different populations.

Follow-up comments

I’m pretty satisfied with the section as a whole; I just have some suggestions for replacing some technical language with simpler language that conveys largely the same meaning.

4. In the first paragraph, it says “Homo sapiens cells”; I would just call them “human cells”.
5. Also, I think it would still be a good idea to give a brief definition of what “pharmacomicrobiomics” means and link to the article on it. I suggest something like “there is considerable potential for interactions between drugs and an individual's microbiome. The study of these interactions is called pharmacomicrobiomics, which include drugs altering the composition of the human microbiome…”
6. As for the second paragraph, we should probably link promiscuous metabolism (needs to be piped) and include a brief definition in a footnote, since I don't feel that the introduction to the Enzyme promiscuity article is all that helpful for a non-expert like me.
7. Replacing human gastrointestinal microbiota with “gut bacteria” would probably be an oversimplification, but if bacteria are mainly responsible for drug metabolism by microbes, could we put say “primarily bacteria” in parentheses afterward?
8. Also, replacing “into blood plasma” with “into the blood” would sacrifice a little precision but would be a little simpler. AmericanLemming (talk) 03:03, 13 August 2019 (UTC)
@AmericanLemming: Sorry about the long delay in my reply; I'd meant to respond earlier but was tied up at the time and forgot about it in the meantime.
4.   Done
5.   Added at the end of the first paragraph: "The field that studies these interactions is known as pharmacomicrobiomics."
6. I think what the authors meant here was that amphetamine is likely a ligand for (i.e., likely metabolized by) many currently unidentified microbial enzymes, not that the enzymes themselves are promiscuous.
7.   Done
8.   Done - changed it to "into the blood stream"
Seppi333 (Insert 2¢) 12:07, 16 August 2019 (UTC)

@AmericanLemming:   Thank you for reviewing that for me! Seppi333 (Insert 2¢) 06:34, 18 August 2019 (UTC)

I find this page to be biased in the emphasis on how safe amphetamines are and that when abused then there are problems. Many people end up with issues at prescribed doses such as withdrawal and dependence which can also be found in research. Mentions how younger kids are less likely to abuse drugs later on in life if they start on amphetamines at a young age. What is skipped is that starting at any other age increases the chance. Ignores acute tolerance which happens within hours of taking the medication and was used to base the design of various extended release products. Ignores many harmful aspects such as oxidative stress, downregulation of receptors and the production of neurotransmitters, neurotransmitter depletion, Instead it only mentions pathways to addiction. Dependence is related, but not mentioned when the brain no longer efficiently manages it's own neurotransmitters and has to rely on the medication to do it. Even at low doses people often feel the Adderall crash when it wears off. All be it mildly. Feels like every section has to say something about it's safe at prescribed doses or implies negative outcomes only for abusers. Seems more like damage control and people trying to sell me on the idea. Safety and what not should be in one section, not in every section as if trying to protect peoples perceptions. Not a single mention of the effects on the endocrine system. Skipped the issue on stunted growth all together. etc. Aside from that, very informative. — Preceding unsigned comment added by 69.248.160.198 (talk) 10:32, 9 April 2023 (UTC)

I don't 🤷 Strawkipedia (talk) 06:29, 8 July 2023 (UTC)
  • Mentions how younger kids are less likely to abuse drugs later on in life if they start on amphetamines at a young age. What is skipped is that starting at any other age increases the chance. That's news to me. Feel free to cite a reliable medical source, and I'd add that information myself.
  • Many people end up with issues at prescribed doses such as withdrawal and dependence which can also be found in research. Yes, it's mild and lasts about a week, if it occurs at all. It's not mild for recreational users, but it still only persists for a few weeks even in the heaviest recreational users. Why does this deserve to be mentioned for people taking therapeutic doses when it's generally subclinical (i.e., doctors and psychiatrists discontinuing the medication don't gradually taper the dose), if it occurs at all, though? Moreover, wouldn't covering this reaffirm your belief that the article is biased in convincing you of safety?
  • Ignores acute tolerance which happens within hours of taking the medication and was used to base the design of various extended release products. What?
  • Ignores many harmful aspects such as oxidative stress, downregulation of receptors and the production of neurotransmitters, neurotransmitter depletion, Feel free to cite some medical sources discussing evidence found in humans, and I'll add it to the article.
  • Skipped the issue on stunted growth all together. You clearly did not actually read the article. It's been covered in Amphetamine#Contraindications for at least the past 6 years.
  • Generally speaking, for a drug that's used clinically and recreationally, why do you expect the article to conflate the effects of clinical low-dose use and recreational high-dose use? It either biases the reader into thinking recreational use is safer than it actually is, clinical use is less safe than it actually is, or both. I don't particularly care whether the inclusion of content makes people think the article is biased. I do care about the omission of content, though.
Seppi333 (Insert 2¢) 19:41, 25 July 2023 (UTC)

WP:FACR: 2c

Latest comment: 4 years ago5 comments2 people in discussion

@Headbomb: You updated 2 page ranges, added 2 pmcs, added 3 issues, and added a missing year in [2]; those were the useful revisions. Meanwhile, you changed some of the abbreviated journal titles to full titles, while leaving e.g., references 101, 102, 103, and 105 abbreviated. All of the journals were consistently formatted before you used a bot to bork the citation formatting (which is why those bots were denied from editing this page before you removed them from the template). You need to consistently format the journal titles in this article or I'm going to revert your edit. It's not my job to clean up after bot edits that inconsistently revise this page's citations. Seppi333 (Insert 2¢) 20:06, 24 December 2019 (UTC)

Should be fixed now. Citations were located in different templates. Headbomb {t · c · p · b} 20:17, 24 December 2019 (UTC)
6, 8, 11, 184, and 188 are all still "J. soandso." Seppi333 (Insert 2¢) 20:35, 24 December 2019 (UTC)
Same reason. Done. Headbomb {t · c · p · b} 20:55, 24 December 2019 (UTC)
@Headbomb: Thanks. With that fixed, your revisions were rather helpful overall. Seppi333 (Insert 2¢) 23:24, 24 December 2019 (UTC)

Abbreviations

Latest comment: 4 years ago5 comments2 people in discussion
  Resolved

@Seppi333: It isn't clear if MOS:FIRSTABBR should apply to citations since they stand alone in their usage. For example, there is no problem with repeating the same link in many citations within an article MOS:REPEATLINK. Whywhenwhohow (talk) 06:22, 25 December 2019 (UTC)

@Whywhenwhohow: I'm familiar with the exception for links in citations; I simply dislike them. When I click something in a citation, I expect to navigate outside WP, not internally. Ignoring the guideline entirely, an abbreviation for a website or publisher entry is just extraneous markup; it doesn't serve any purpose like it does in the article text.
Anyway, can you restore the publisher parameters in the citations to the FDA website that you changed to DailyMed? It should be listed as the manufacturer; regardless of what website hosts the prescribing information, the publisher would still remain the same. I already restored a few, but there's others that need to be fixed. Seppi333 (Insert 2¢) 06:58, 25 December 2019 (UTC)
Yes, but why do you prefer the ones from the FDA website? They are PDF format and harder to navigate? The NIH DailyMed website is the official provider of FDA label information Whywhenwhohow (talk) 08:27, 25 December 2019 (UTC)
I don't have a fixed preference for DailyMed or the FDA's labels as a citation since both have an advantage over the other; the actual content is identical though. The PDFs have page numbers which makes verifiability easier when the prescribing information is rather long, but DailyMed is easier to navigate given its design. I'm just used to citing FDA labels since I've always used Drugs@FDA to search for drug information (e.g., the label itself, approval data, and information on current/actively marketed brands as well as discontinued drug products associated with the active ingredient I'm searching).
In any event, I just realized that I worded my earlier request about the publisher information very poorly; what I meant to say was to restore the publisher parameters from the FDA citations in the DailyMed citations. Databases like Drugs@FDA and DailyMed that host a drug label online should always just be listed in the website/work parameter of {{cite web}}, so you were doing that part correctly. The publishers are the entities that write/edit and produce a document, which in this case is the prescribing information − i.e., pharmaceutical companies like Shire Plc, Hoffmann-La Roche, Merck & Co, etc.. While the FDA approves prescribing information for drugs, the drug label for any given drug is the copyrighted intellectual property of the manufacturer/pharmaceutical company that produces the drug because they're the authors of the corresponding drug label; that's why they're listed as the publisher for drug labels. I've added the original citation templates below as an example. In any event, I'll go ahead and fix the DailyMed citations since you already spent time actioning my poorly worded request. Seppi333 (Insert 2¢) 09:59, 25 December 2019 (UTC)
They're all fixed now. If you want to change the 2 FDA drug label citations I added to DailyMed citations, feel free to do so. I don't really care which one we use. Seppi333 (Insert 2¢) 10:19, 25 December 2019 (UTC)
Drug label citation templates
  1. {{cite web|title=Adderall IR Prescribing Information|url=www.accessdata.fda.gov/drugsatfda_docs/label/2015/011522s042lbl.pdf|publisher = Teva Pharmaceuticals USA, Inc.|work = United States Food and Drug Administration|date=October 2015|accessdate=18 May 2016|pages=1–6}}
  2. {{cite web|title = Adderall XR Prescribing Information|url = www.accessdata.fda.gov/drugsatfda_docs/label/2013/021303s026lbl.pdf|page = 11|publisher = Shire US Inc.|work = United States Food and Drug Administration|date=December 2013|accessdate = 30 December 2013}}
  3. {{cite web|title=Evekeo Prescribing Information|url=www.evekeo.com/assets/evekeo-pi.pdf|publisher=Arbor Pharmaceuticals LLC|accessdate=20 July 2018|pages=1–2|date=September 2016}}
  4. {{cite web|title=Dyanavel XR Prescribing Information|url=www.accessdata.fda.gov/drugsatfda_docs/label/2017/208147s003lbl.pdf|publisher= Tris Pharma, Inc.|work=United States Food and Drug Administration|accessdate=4 August 2017|pages=1–14|date=May 2017|quote=DYANAVEL XR contains d-amphetamine and l-amphetamine in a ratio of 3.2 to 1 ... The most common (≥2% in the DYANAVEL XR group and greater than placebo) adverse reactions reported in the Phase 3 controlled study conducted in 108 patients with ADHD (aged 6–12 years) were: epistaxis, allergic rhinitis and upper abdominal pain. ... <br />DOSAGE FORMS AND STRENGTHS<br />Extended-release oral suspension contains 2.5 mg amphetamine base per mL.}}
  5. {{cite web|title=Vyvanse Prescribing Information|url=www.accessdata.fda.gov/drugsatfda_docs/label/2017/021977s045,208510s001lbl.pdf|pages = 3–13, 17–21|website = United States Food and Drug Administration|publisher = Shire US Inc.|accessdate=10 July 2017|date = May 2017}}
  6. {{cite web|title=Mydayis Prescribing Information|url=www.accessdata.fda.gov/drugsatfda_docs/label/2017/022063s000lbl.pdf|website=United States Food and Drug Administration|publisher=Shire US Inc.|accessdate=8 August 2017|pages=1–21|date=June 2017}}
  7. {{cite web|title=Adzenys XR-ODT Prescribing Information|url=www.accessdata.fda.gov/drugsatfda_docs/label/2017/204326s002lbl.pdf|website = United States Food and Drug Administration|publisher=Neos Therapeutics, Inc.|accessdate=10 August 2017|page=16|date=January 2017|quote = ADZENYS XR-ODT (amphetamine extended-release orally disintegrating tablet) contains a 3 to 1 ratio of d- to l-amphetamine, a central nervous system stimulant.}}

Page size

Latest comment: 4 years ago9 comments3 people in discussion

At 241,890 bytes of wiki markup, this page is far too large. That's particularly troubling for a page listed as a featured article. How can it best be divided? For example, splitting off the entire 'Pharmacology' section would remove over a fifth of that (less if a summary is kept here). Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 11:19, 2 January 2020 (UTC) @Pigsonthewing:

Document statistics:
File size: 989 kB
Prose size (including all HTML code): 123 kB
References (including all HTML code): 25 kB
Wiki text: 236 kB
Prose size (text only): 49 kB (6811 words) "readable prose size"
References (text only): 2506 B
User_talk:Dr_pda/prosesize.js
To quote WP:TOOBIG: These rules of thumb apply only to readable prose and not to wiki markup size (as found on history lists or other means), and each kB can be equated to 1,000 characters.
I'm not even going to consider splitting this article right now given that it's not even that long by the actual guideline metric. Seppi333 (Insert 2¢) 11:43, 2 January 2020 (UTC)
Wow, four bigs, and and underline? -- Mikeblas (talk) 19:56, 12 July 2020 (UTC)
"I'm not even going to consider..." That's OK, you're not required to participate. But in declaring that you're not participating, please don't selectively quite only parts of a guideline, as you do - unnecessarily garishly - above. The guidleline also says, near the top of the page (and so before the subsection you quote): "There are three related measures of an article's size: Readable-prose size [...] Wiki markup size [and] Browser-page size". Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 12:05, 2 January 2020 (UTC)
Yes, and the guideline says absolutely nothing about hard-limits on markup size like it does with the prose size, which you clearly are trying to use as a justification for splitting pages based upon their on markup size. The thing is, this page might have a markup size in the 200+kB range, but both this script and xtools indicate that the prose size is 49-50kB. No one is going to buy what you are selling if you keep trying to argue that this page needs to be split based upon markup size. And even if that was an issue, which it clearly is not, I could simply move this entire page's source code to a template and transclude it in, causing this page's markup size to drop to <10kB while the readable prose size remains the same. Seppi333 (Insert 2¢) 12:14, 2 January 2020 (UTC)
Not so; for example the guideline says: "The text on a 32 kB page takes about five seconds to load for editing on a dial-up connection, with accompanying images taking additional time, so pages significantly larger than this are difficult for older browsers to display. Some large articles exist for topics that require depth and detail, but typically articles of such size are split into two or more smaller articles. ". Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 12:21, 2 January 2020 (UTC)
I don't see a hard/fixed limit anywhere in the text you quoted. It appears to assert the incredibly obvious fact that shittier connections load webpages more slowly, and we're talking about two-tenths of one megabyte. Seppi333 (Insert 2¢) 12:26, 2 January 2020 (UTC)
Wikipedia talk:Article size is available, should you wish to dispute the contents of the guideline. Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 12:50, 2 January 2020 (UTC)
@Pigsonthewing: Dispute the guideline? Why would I do that? It supports my assertion and contradicts yours. I'm actually happy with it the way it is. Also, thank you again for the nomination. You're doing me a favor here. Seppi333 (Insert 2¢) 13:15, 2 January 2020 (UTC)
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