Changes in human platelet 5 HT level after 1 week of chlorimipramine treatment.

In platelets of six volunteers taking chlorimipramine (50 mg/day) for 1 week, 5-HT levels were markedly decreased at the time of treatment withdrawal, and remained significantly reduced after a 1-week washout. Individual levels in five subjects remained affected during a 3-week washout. The previously reported observations of reduced serotonin concentration in platelets from depressed patients may reflect a residual effect of previous antidepressant treatment.