Sunday, February 17, 2008

Caffeine and antidepressant medications

Over the short term (one day on meds), imipramine (Tofranil)and amitriptyline (Elavil) decreased, while fluoxetine (Prozac) accelerated the overall metabolism of caffeine. Nefazodone(Serzone) also stimulated metabolism, but through a more indirect pathway. To say it another way, the body more rapidly broke down and inactivated caffeine under the influence of these medications.

Fluoxetine given chronically increased an indirect pathway of caffeine metabolism. Sertraline (Zoloft) and mirtazapine (Remeron) enhanced the rates of all caffeine oxidation pathways.

I must qualify this study was done on rats, not humans, and I can't remember the last time I saw a rat in line chumming it up with the barista. Even so, it's not unreasonable to assume the same effects could be seen in humans.

So...if you're feeling like your Prozac may have reduced the effect of your double caf skinny no foam morning treat into a half caf regular cup of may not be your imagination!

Don't let that drug influence tempt you into buying a frequent flyer card at your local coffee haunt, though. Excess caffeine is associated with insulin resistance which can aggravate weight gain. Better to focus on better sleep habits (and less late night web sudoku)than on better productivity through chemical stimulation.

Kot M, Wójcikowski J, Daniel WA. Caffeine metabolism during prolonged treatment of rats with antidepressant drugs. Pharmacol Rep. 2007 Nov-Dec;59(6):727-33.

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