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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 3 of 3. This is the beginning of the thread.
Posted by S.D. on November 12, 2006, at 12:23:28
Is it dangerous to take diphenhydramine for insomnia while on Effexor (venlafaxine), Is it equivalent to taking a larger dose of Effexor. What I'm talking about is the fact that Effexor is metabolized mainly by CYP2D6, and diphenhydramine inhibits the activity of this enzyme.
The article http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11270914&dopt=Abstract ( or if that link isn't permanent then http://www.biopsychiatry.com/venbenadryl.htm) concludes "Clinically significant interactions could be encountered". When I read about Benadryl easing Effexor withdrawal I figured this accounted for it -- it causes the Effexor to diminish more slowly, which would also mean an effectively greater dose if you kept taking Effexor.
But on on the other hand the effect on Effexor would be the same as if you were, by genetics, a "poor metabolizer" of CYP2D6 -- and rxlist.com (http://www.rxlist.com/cgi/generic/venlafax_cp.htm, "Metabolism and Excretion" heading) states taht "The differences between the CYP2D6 poor and extensive metabolizers, however, are not expected to be clinically important because the sum of venlafaxine and ODV is similar in the two groups and venlafaxine and ODV are pharmacologically approximately equiactive and equipotent."
And my current doctor said there could be a significant effect only at uncommonly high doses of both substances (he is quirky, hard to figure, and it wouldn't be the first time to get bad advice from a good p-doc, but I'm not rocking the boat because he doesn't out of hand reject benzodiazepines (clon. for social phobia)).
I have periods of insomnia fairly frequently and Effexor can cause it too, so I need something I can safely take -- preferably without prescription so I can reliably take it as needed *when* I need it (2 weeks advance for dr. appointment doesn't help much, and anyway as I said, mine is hard to figure.)
thanks
- S.D. (shyInSanDiego)
Posted by Lindenblüte on November 12, 2006, at 22:28:29
In reply to How much is Effexor affected by diphenhydramine?, posted by S.D. on November 12, 2006, at 12:23:28
hi SD,
sorry- I have no answer for your question. My doc told me specifically that no OTC cold medicine would interact with cymbalta. He's a phantastic psychpharm doc, so I'm going to take him at face value.Having said that, I don't know if cymbalta uses the same metabolic pathway as diphendydramine. I doubt it, in fact.
How about getting a script for 25mg of seroquel. It is a mood stabilizer that works REALLY well for helping put me to sleep. It is an effective antidepressant at higher doses. I take 300m now, but I remember the days when 12.5 would knock me out. I took 12.5 to 50mg for about 4 months. It always worked, and I didn't require higher and higher doses to put me asleep.
so, you can experiment to find the smallest dose that knocks you out, and your doc can give you unlimited refills. It's cheap!
just a thought. :)
oh- seroquel "augments" AD effects of cymbalta, maybe it does for effexor as well.
right now it's putting me to sleep. I can hardly concentrate, but my clothes are still in the dryer. DARN!
-Li
Posted by S.D. on November 17, 2006, at 18:01:29
In reply to Re: How much is Effexor affected by diphenhydramin » S.D., posted by Lindenblüte on November 12, 2006, at 22:28:29
hi,
thanks for the info. I have in fact tried seroquel for sleep just as you mentioned, on the advice of a previous doctor. I could take a little (i don't recall the milligrams) to feel a little sleepy (my understanding is it is a strong antihistimine and that this likely the reason how/why it helps for insomnia), but more than a little was awful for me -- dizzy and generally nasty side effecty feeling, I couldn't stand it.-S.D.
This is the end of the thread.
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