The effect of multiple rising doses of Ro 11-2465 (serotonin uptake inhibitor) on serotonin content of human platelets

Ro 11-2465, a cyanide derivative of imipramine with serotonin uptake inhibitory properties, was investigated in six healthy volunteers for its effect on serotonin concentration in blood platelets. The initial dose was 1 mg daily, the maximum dose of 3 mg being reached on day 3 and maintained for 7 days.A significant decrease in the platelet serotonin concentration was not observed until 3 days after the start of drug administration, after which depletion was rapid. After 5 days of treatment, the reduction was about 80% compared to predrug level. Serotonin restoration after drug withdrawal was very slow, and 5 days after discontinuation, it was still 70% below its baseline level.