Posted by Sad Panda on November 16, 2004, at 9:49:14
In reply to Re: prozac + nortripyline pharmacology questions, posted by King Vultan on November 16, 2004, at 9:08:47
This PubMed extract demonstrates how bad Prozac is.
"Effect of venlafaxine versus fluoxetine on metabolism of dextromethorphan, a CYP2D6 probe.
Amchin J, Ereshefsky L, Zarycranski W, Taylor K, Albano D, Klockowski PM.
Wyeth-Ayerst Laboratories, 240 North Radnor-Chester Road, St. Davids, PA 19087, USA.
Two antidepressants, venlafaxine and fluoxetine, were evaluated in vivo for their effect on cytochrome P450 2D6 (CYP2D6) activity, measured by the ratio of dextromethorphan, a sensitive CYP2D6 marker, to its metabolite dextrorphan (i.e., DM:DT) excreted in urine after DM coadministration. Twenty-eight healthy extensive metabolizers of CYP2D6 received either venlafaxine (37.5 mg bid for 7 days, then 75 mg bid until Day 28) or fluoxetine (20 mg daily for 28 days); 26 completed the study. Plasma concentrations of both drugs and their active metabolites were determined. DM:DTs were evaluated at baseline (Day 0), on Days 7 and 28 of dosing, and 2 weeks after drug discontinuation (Day 42). Steady-state drug and metabolite levels were achieved in both groups by Day 28. Mean DM:DTs for venlafaxine and fluoxetine differed statistically significantly (p < 0.001) on Days 7, 28, and 42. Comparisons of DM:DT as a percentage of baseline values showed that DM:DT increased 1.2-fold for venlafaxine and 9.1-fold for fluoxetine on Day 7 (p < 0.001) and increased 2.1-fold for venlafaxine and 17.1-fold for fluoxetine on Day 28 (p < 0.001). Inhibition of CYP2D6 metabolism persisted for 2 weeks after discontinuation of fluoxetine, unlike the case with venlafaxine. These in vivo results confirm in vitro data demonstrating significantly weaker inhibition of CYP2D6 with venlafaxine than with fluoxetine. This suggests that clinically significant interactions involving CYP2D6 inhibition could occur between fluoxetine and drugs metabolized by CYP2D6 but may be less likely to occur with venlafaxine."
There are a couple of posters here who use Prozac to boost Effexor levels, this is a very dangerous comination for the majority of people, but is fine for ultra fast 2D6 metabolizers. I consider myself to be an average metabolizer of drugs that use 2D6 & have combined 150 mg of Effexor with 125+mg of Nortriptyline. It's worth noting that I find codiene relatively useless these days as it uses 2D6 too.Cheers,
Paul.
poster:Sad Panda
thread:416518
URL: http://www.dr-bob.org/babble/20041113/msgs/416640.html