Talk:Medroxyprogesterone acetate

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Difference between Medroxyprogesterone acetate and Medroxyprogesterone[edit]

From RD/S and WT:MED

Hola,

I'm trying to figure out the difference between medroxyprogesterone versus medroxyprogesterone acetate. Anyone know? Anyone have any sources that can be used to distinguish the two? WLU (t) (c) Wikipedia's rules:simple/complex 01:57, 3 July 2010 (UTC)

Other than the obvious difference in chemical structure, what are you looking for? It appears that the 17-acetate is the only one used medically - both of the references in the MP article actually relate to MPA. The Merck Manual entry indicates that the former is "supplied as the acetate". The article in MedlinePlus uses the terms interchangeably. Many references discuss plasma levels of MPA, so my initial impression that the acetate is readily hydrolyzed is probably false. -- Scray (talk) 02:59, 3 July 2010 (UTC)

the following 4 posts were copied from WikiProject Medicine, as discussed there

(Original research alert) First, pregnanes and progestins are not mutually exclusive. Pregnane refers to the structure of the molecule, while progestin refers to its biological activity. Medroxyprogesterone is the active molecule. In order to stabilize medroxyprogesterone in a form that can be administered orally or intravenously, it's acetylated (see the final step in File:Medroxyprogesterone_acetate.png. In the body, the acetate residue is degraded and you get the active molecule back.

If you're talking about administering medroxyprogesterone as a pharmaceutical, then you're technically talking about MP acetate. If you're talking about steroid biochemistry in vivo, then it's more correct to refer to medroxyprogesterone, period. I'm not sure what implications this has for our article structure (and this is just me talking - it's been awhile since I took pharmacology, and I don't have a supporting source at my fingertips, so take it with a grain of salt because I have been known to be wrong). MastCell Talk 03:58, 3 July 2010 (UTC)

MastCell, thanks for correcting me (pending further corroboration/refs). That was my initial sense (see the RD/S history for my original comments if curious) but I couldn't quickly find anything reliable that supported me. I'll look again tomorrow if no one weighs in further. -- Scray (talk) 04:02, 3 July 2010 (UTC)
I wish I had some refs handy to back me up. BTW, I saw your comment at the Ref Desk about MPA levels ([1]). Are you sure those are actually looking at levels of medroxyprogesterone acetate? I'm not familiar with measuring levels of it. On the other hand, there's an extensive literature on monitoring plasma levels of mycophenolic acid (also abbreviated MPA), which is the active metabolite of mycophenolate mofetil (MMF). Like most immunosuppressants, MMF pretty finicky and has a narrow therapeutic window, so a lot of work has been done on MPA pharmacokinetics (mycophenolic acid) in the organ transplantation literature. You've probably already looked into this, but is it possible that the "MPA" levels you saw were actually mycophenolic acid, rather than medroxyprogesterone acetate? MastCell Talk 04:30, 3 July 2010 (UTC)
I'm very familiar with mycophenolate; the particular paper that made me doubt myself was this one, which led me to PMID 6457936, which is entitled "Medroxyprogesterone acetate in human serum". On re-reading the abstract, this may simply be sloppy terminology, since the RIA they're using might not distinguish medroxyprogesterone from the acetate. Clarity remains elusive, but I think you're probably right. -- Scray (talk) 05:01, 3 July 2010 (UTC)

end of material copied from WikiProject Medicine -- Scray (talk) 05:14, 3 July 2010 (UTC)

From WT:DRUGS

Both are pregnanes (that' the steroid framework) and both are progestins (i. e. synthetic progesterone derivatives). The acetate is more lipophilic and is therefore better resorbable. It is split into medroxyprogesterone and acetate in the body. I'm not aware of medroxyprogesterone being used directly. --ἀνυπόδητος (talk) 09:02, 3 July 2010 (UTC)
I can't quickly find any free sources to back this up, but MPA may act as a prodrug of medroxyprogesterone (for example to prevent phase II metabolism). On the other hand, MPA itself may have appreciable binding affinity for the progesterone receptor and act as an agonist (see for example PubMed). Also it is not clear how rapidly it is hydrolyzed. Hence it may not be a true prodrug. Finally MPA is the active ingredient of Depo-Provera which can be used as a injectable contraceptive whose effects last for months. Hence the reason for the acetate ester maybe to increase the hydrophobicity and thereby increase the half-life of the drug. Boghog (talk) 12:00, 3 July 2010 (UTC)
According to this PubMed source:
Ligand PR Ki (nM) Conformation EC50 (nM) Reporter cell line EC50 (nM)
Progesterone 4.3±1.0 0.9±0.2 25±11
Medroxyprogesterone acetate 1.2±0.3 0.6±0.08 0.15±0.03
Medroxyprogesterone 241±96 47±14 32±1
Hence both medroxyprogesterone (MP) and medroxyprogesterone acetate (MPA) bind to the progesterone receptor and both are agonists, but MPA has approximately 100X the binding affinity and transactivation potency compared to MP. Furthermore, according to this PubMed source, MPA is hydrolyzed to MP in baboons, but the hydrolysis rate appears to be modest. Therefore most of the activity of injected MPA probably results from the parent drug rather than the hydrolysis product. Finally many papers claim to use MP but are really using MPA (see for example PubMed, "Medroxyprogesterone was provided as Depo-Provera"). Boghog (talk) 18:48, 6 July 2010 (UTC)

Merge from medroxyprogesterone[edit]

Given these comments, what about a page merge into from medroxyprogesterone? It seems like it would be relatively trivial to combine the two with statements saying they're often referred to interchangeably, but noting the differences that do exist (i.e. "Medroxyprogesterone acetate degrades into is often administered as an acetate (as medroxyprogesterone 17-acetate), with X, Y and Z differences in characteristics"). Given most sources use the terms interchangeably, it seems more unnecessary work to disentangle than to distinguish at the top. Tough call. WLU (t) (c) Wikipedia's rules:simple/complex 14:31, 12 July 2010 (UTC)

I think it would greatly clarify things if we could find a single unambiguous example of MP being used clinically. All the medroxyprogesterone package inserts that I have looked at (see for example) indicate that the active ingredient is MPA and not MP. Hence I am beginning to seriously doubt whether MP has ever been used clinically.
Currently the {{chembox}} template is used in the MPA article while {{drugbox}} is used in the MP article which is as far as I am concerned is backwards. If the article are not merged, it would be appropriate to swap the templates (of course also updating each template so that the templates drugbox template contains information about MPA and the chembox template contains information about MP). If the articles are merged, I think it would be far more appropriate that the MP article be merged into MPA and not the other way around. Many sources use the names MP and MPA interchangeably however I think this is sloppy practice. What is being administered is MPA and not MP, and while MPA can be metabilized into MP, the later is much less active than the former. Boghog (talk) 20:20, 12 July 2010 (UTC)
Not surprisingly, I agree (I should really have reversed the merge tags and direction). One thing I would really like would be sure on is the differences between the two, but I've had little luck tracking down an article that differentiates them. I'll keep poking at it over the next couple days, and I've asked User:Arcadian for his/her input - hopefully others will provide some input (and sources) as well. I'll start trolling for medroxyprogesterone - acetate. WLU (t) (c) Wikipedia's rules:simple/complex 00:51, 13 July 2010 (UTC)

paste from talk:Medroxyprogesterone

Unless someone can find an unambiguous example where medroxyprogesterone (MP) and not medroxyprogesterone acetate (MPA) is used clinically, I support the merger. However since it appears that only MPA has been used clinically, I think the direction of the merger should be reversed (i.e., merge MP into MPA). Boghog (talk) 20:27, 12 July 2010 (UTC)
Agree with BogHog.--Literaturegeek | T@1k? 01:02, 13 July 2010 (UTC)
Agreed also, corrected direction of merge on this and other pages. Apologies for the mess. WLU (t) (c) Wikipedia's rules:simple/complex 04:00, 13 July 2010 (UTC)

end paste

I oppose the merge. The community at Wikipedia:WikiProject Chemistry places a priority on not merging related compounds into single articles. They're working to have the infobox uniquely identify precise compounds, and I support that initiative. Also, because of the controversy over the terminology involved, it is important that we minimize the assumptions made in our articles about which terms imply which other terms. Just because the scientific literature is sometimes sloppy doesn't excuse the same imprecision on our part. (Indeed, in the long run, our precision may help drive the literature. Research assistants will read this page, and subtly nudge their supervisors to use the correct terminology.) Instead I recommend we use hatnotes at the top of each page to clarify the subject under discussion. --Arcadian (talk) 12:40, 24 July 2010 (UTC)
Arcadian, do you have any suggestions for how to distinguish between the two? One of the difficulties I've found is trying to figure out when someone is using MP versus MPA. I have essentially no biochemistry background and it's very hard to tell the difference. WLU (t) (c) Wikipedia's rules:simple/complex 14:18, 24 July 2010 (UTC)
I don't have any problem leaving the MP article in place. However unless someone is able to find a unambiguous example of where MP has been used clinically, the scope of the MP article should be restricted to chemistry and in vitro pharmacology and mention that MP is a metabolite of MPA. Furthermore the sections on "uses", "adverse effects", and "comparison to progesterone" should be merged into the MPA article. As far as how to distinguish MPA from MP, we should make clear that MPA is the clinically used drug while MP is a research tool that shares some of the same pharmacological effects as MPA, but is much less active. Boghog (talk) 17:28, 24 July 2010 (UTC)
I have been bold and (1) added hatnotes to try to distinguish between MP and MPA, (2) swapped the chem and drug infoboxes, and (3) moved the "uses", "adverse effects", and "comparison to progesterone" sections from the MP to the MPA article. Both articles could use better citations that discuss the differences between MP and MPA, but I have not been able to find any. Boghog (talk) 07:01, 25 July 2010 (UTC)
Thanks BH. If you do find any that usefully make the distinction, I wouldn't mind a copy and may get around to integrating the information. WLU (t) (c) Wikipedia's rules:simple/complex 08:11, 25 July 2010 (UTC)
If l find any better citations, I will certainly post them here and add them to the articles. Per the above discussion, I have taken the liberty of taking down the merge banners. Boghog (talk) 11:32, 28 July 2010 (UTC)

Review[edit]

Yup, considerable expansion using the Merck manual, but I'm really not sure what is appropriately medroxyprogesterone and what is the acetate. A review would be deeply appreciated. WLU (t) (c) Wikipedia's rules:simple/complex 02:00, 10 July 2010 (UTC)

Sources[edit]

Pharmacokinetics vs Pharmacodynamics[edit]

I'm no doctor, but I believe that the material in the Pharmacokinetic and Pharmacodynamic sections are mixed up. The way I remember it: PharmacoDynamic = Drug on body, and the other one is the other one (Pharmacokinetics = body on drug). So stuff like oral absorption, half-life, and bioavailability should be in Pharmacokinetics section (whereas stuff like what the drug is doing to the body should be under Pharmacodynamics). Also, I lied, I'm a doctor. —Preceding unsigned comment added by 71.239.52.169 (talk) 21:47, 6 November 2010 (UTC)

Thanks for the heads up. I have swapped the section headings. In addition some pharmacodynamic text was mixed in with the pharmacokinetic text. This has now been cleanly separated. Boghog (talk) 22:15, 6 November 2010 (UTC)