The pharmacokinetics of nicardipine have been studied following oral and intravenous administration in man and the effects of food on nicardipine kinetics investigated. Following intravenous administration of nicardipine as an infusion plasma levels declined in a biphasic manner and plasma clearance values were of the same order as hepatic plasma flow. Following oral administration in the starved state nicardipine was rapidly absorbed but subject to presystemic elimination. Maximal plasma concentrations were achieved typically between 20 minutes and 2 hours after administration. The oral bioavailability of nicardipine determined by reference to a co-administered intravenous radiolabelled dose was found to be non-linearly related to dose. Bioavailability ranged from 15-45% approximately over the dose range 10-40 mg. Administration of nicardipine following a meal reduced the bioavailability of nicardipine.