Effexor compared to prozac as inhibitors of CYP2D6.

Hello fellow bluelighters.
I've been taking 60mgs of prozac a day for a while now for OCD/anxiety disorders. It's helped my disorders a great deal and despite certain side effects i'm overall pleased with its effect.

But prozac as an inhibitor of CYP2D6 (and SSRI) is limiting me in terms of recreational drug use. I find that i dont get the same effects from codeine/oxycodone/hydrocodone or any other drug that is converted by CYP2D6 into other metoblities.

Anyways, I've been searching around and I've found that Effexor (Venlafaxine
) is a much weaker inhibitor of CYP2D6. Additionally it has a much shorter half-life so I was also wondering if theoritically by skiping a days or two dose I could clear up my CYP2D6 metoblites (yes, I'm aware of the fact that effexor is known to cause withdrawl effects after even one skipped dose).

Bassically my questions are exactly how powerful is Effexor as CYP2D6 inhibitor? How safe is it to combine effexor with tramadol/dxm the same day and after after a few days off Effexor? Also, If i decide to switch from prozac to effexor, will i have to stop useing the prozac for a few weeks before i can start the effexor treatment?

P.S. here is another good thread dealing with the same subject: http://www.bluelight.ru/vb/showthread.php?t=405117

Thx for your help.

Oh cmon, bump.

Does anyone know atleast which SSRI/SNRI is the weakest CYP2D6 inhibitor?

As far as I know, enzyme inhibitors really shouldn't be an issue while taking opiates, namely oxycodone/hydrocodone as they are not pro-drugs and are potent analgesics in their own right. The only drug you listed that might be affected by enzyme inhibition is codeine as it will be broken down to morphine. However, this really should not matter that much. I am very weary to say that SSRI's and effexor(SNRI) will have any detrimental effects to opiates whatsoever. And while I am not 100% sure that these are even enzyme inhibitors(someone correct me if I'm wrong) I have been on prozac and effexor and have not felt that they had any effect on opiates, namely the ones mentioned in your post.

If you really feel that you can't feel opiates as strongly when you are on these meds, I would re-evaluate, take an inventory of anything else you are on and perhaps modify your dose.

As for your the effexor tramadol question, we don't really know the pharmacokinetics associated with tramadol and the serotonin system. While we do know that it effected, as far as I know the mechanism of action is still unkown...

Well inhibitors of CYP2D6 certainly reduce the effects of these opiates. Don't forget oxycodone is metoblized by the P450 enzyme into oxymorphone, and the same with hydrocodone and hydrocodone and Hydromorphone.

Bump, fluvoxamine apperantly is the weakest CYP2D6 inhibitor out of all the comon SSRI's.
It should be noted that it has a very short half life though and inhibits enzyme CYP1A2, it should be mentioned that tobacco smoke is a potent inducer of CYP1A2 and there doses in patience whom smoke should be adjusted accordingly.

The majority of oxycodone's effects come from the drug itself, not it's metabolites. Same with hydrocodone, there are studies showing the amount of metabolite of oxymorphone and hydromorphone respectively are very low, negligible even.

Codeine on the other hand will be affected.

Around what percent of hydro/oxycondone's high comes from its metabolites?
negligible you say? Because from my experience it's deffiently not negligible, not saying your wrong, I just feel that it's not negligible as you might think.

WSB15 said:

Off the top of my head, I believe Celexa and Lexapro have very little to none, while Luvox and Prozac are the strongest inhibitors. That's just off the top of my head I could be thinking of 3A4 instead. I'd double check but I gotta roll out.

FWIW, in my experience there was no difference in strength taking oxy/hydrocodone on or off Prozac although I see what you're saying about theoretical diminishing of their effects. It did make buprenorphine and methadone stronger and longer lasting.

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Luvox is the weakest CYP2D6 inhibitor. Prozac and paxil are the strongest. You are right about CYP2D6 inhibitors making bup and methadone stronger but im more intrested in oxycodone as I use it more often.