The pharmacokinetics of ketanserin after a single dose and at steady-state in hypertensive subjects

Summary

We have studied the pharmacokinetics of ketanserin in 6 hypertensive patients after a single oral 40 mg dose and at steady-state after 4 weeks treatment with 20 mg and then 40 mg 12-hourly.

Pharmacokinetic variables after a single dose were similar to those reported in healthy volunteers, with median values for C_max 112 ng·ml⁻¹, t_max 1 h, and t_1/2 19 h. The corresponding values for the metabolite ketanserinol were C_max 155 ng·ml⁻¹, t_max 2 h, and t_1/2 25 h. The median AUC was 3.3 times greater for ketanserinol than for the parent drug.

These results were used to predict the mean steady-state plasma concentrations of ketanserin and ketanserinol. Predicted values were on average similar to those observed after four weeks treatment with 40 mg 12-hourly, although there were marked differences between the observed and predicted values in some patients.

There was no evidence of time- or dose-dependent kinetics for ketanserin, but the study had insufficient power to exclude the occurrence of these phenomena entirely.