Posted by Brainbeard on October 3, 2009, at 13:13:16
In reply to HELP! Amitriptyline and lexapro combo question!!, posted by fellowmike on October 3, 2009, at 0:20:11
The only enzyme group that Lexapro moderately inhibits is 2D6. Amitriptyline, on the other hand, inhibits a bunch of enzymes, among which is 2C19, which it inhibits strongly.
And what do you know? 2C19 is one of the main group of enzymes metabolizing Lexapro. Further, 2D6 is one of the enzyme groups metabolizing amitriptyline, and it's essential to break down amitriptyline's active metabolite, nortriptyline.
So, combining Lexapro and amitriptyline will:
*) raise amitriptyline blood levels slightly
*) raise nortriptyline (active metabolite) blood levels more significantly (Prozac, which is a potent 2D6 inhibitor, raised nortriptyline levels about ninefold in this study: http://www.ncbi.nlm.nih.gov/pubmed/7751409)
*) raise Lexapro blood levels significantlyNortriptyline is an NRI (noradrenaline reuptake inhibitor), but a pretty mellow one. It's the least toxic TCA around, so blood levels would have to be very high to become dangerous.
All in all, you're getting more of everything. You could start with 5mg of Lexapro and cutting down your amitriptyline to, say, 75mg. I would ask for a blood level check after about a month. Obviously, they should check your nortriptyline blood levels too! If your blood levels don't run crazy and/or you're not experiencing troublesome side-effects (in which case you should immediately lower your amitriptyline intake), you could first try raising the Lexapro to 10mg, and wait another month, have another blood level check, and then slowly raise the amitriptyline again. Or you could keep the Lexapro at 5mg and slowly raise the amitriptyline.
I think this could be a very good combo, you just have to be careful because there are some significant interactions.
poster:Brainbeard
thread:919493
URL: http://www.dr-bob.org/babble/20091001/msgs/919548.html