Posted by Down on the Upside on August 9, 2008, at 3:00:43
In reply to Re: Fluoxetine + TCA = major toxcity? » Down on the Upside, posted by Crotale on August 8, 2008, at 3:35:43
Thanks for replying Crotale. Well I tried a few 20mg doses of fluoxetine and the depression got horrendously worse than baseline. Dunno if my body has some weird paradoxical to too much serotonin because I also feel this horrible when I take the amitryptiline daily instead of at night. Thankully it's much better after a week or so. That's one experiment I'm not likely to try again.
> Yes, TCA + fluoxetine is a combo that should only be used with extreme caution. The way to do it, if there isn't a safer alternative, is reduce SSRI dose, then titrate and monitor TCA level carefully. Talk to your doctor for more info, and don't do this except under your doc's supervision!!!
>
> TCAs have a very narrow therapeutic index - that is, the toxic dose isn't much higher than the effective dose. Besides the potential for drug interactions, some people are deficient in one of the enzymes involved in TCA metabolism due to a mutation in CYP2D6 (possibly other cytochrome P450 genes, but inhibition of 2D6 is definitely known to cause elevated TCA levels).
>
> I had a bad reaction to desipramine, and it turned out my serum level was elevated to several times the expected level. I still am not sure whether it was me or an unexpected drug interaction. (I wasn't taking an SSRI or any other drug known to raise tricyclic levels.) I had what they think was a seizure but the cardiotoxic effects of TCAs can be fatal in overdose.
>
> Be careful!
>
> -Crotale
poster:Down on the Upside
thread:844000
URL: http://www.dr-bob.org/babble/20080805/msgs/845112.html