The effect of ketanserin on blood pressure and platelets during cardiopulmonary bypass

Ketanserin, a serotonin antagonist, was used to control blood pressure during cardiopulmonary bypass in 12 patients having cardiac surgery. The drug was administered as a 10 mg bolus followed by a continuous infusion of either 40, 80, or 120 mg/hr to maintain mean arterial blood pressure below 70 mm Hg. There were 16 hypertensive episodes of which 15 (93.7%) were successfully controlled with ketanserin. Mean arterial pressure decreased significantly from an average of 72 +/- 3 to 52 +/- 9 mm Hg after 1 min. The effect that ketanserin had on platelets was also evaluated. Neither adverse nor salutary effects were seen in the platelet count, though a significant inhibition of serotonin-induced platelet aggregation was observed. Ketanserin proved effective for controlling hypertension during cardiopulmonary bypass but, despite inhibition of serotonin-induced platelet aggregation, it did not prevent thrombocytopenia.