Ketanserin is a potent antagonist of the serotonin (5-HT) receptor that is selective for 5-HT2 (IC50 = 6.3 nM; Ki = 2.1 nM). It has no activity at 5-HT1 receptors but does have activity at histamine type 1, α1-adrenergic, and dopamine receptors with Ki values of 10, 10, and 220 nM, respectively. Ketanserin induces dose-dependent inhibition of contractile responses to 5-HT in isolated rat caudal artery, canine basilar, carotid, coronary and gastrosplenic arteries, and canine gastrosplenic and saphenous veins. Ketanserin (10 mg/kg/day) significantly decreases blood pressure (BP), blood pressure variability (BPV), and hypertensive organ damage in spontaneously hypertensive rats. Formulations containing ketanserin have been used to treat hypertension in early-onset preeclampsia.
