Pancopride (LAS 30451, CAS 121650-80-4) is a new selective 5-hydroxytryptamine3 receptor antagonist which has demonstrated antiemetic properties in animal models. The tolerance and pharmacokinetics of pancopride and its effect on the 5-hydroxytryptamine flare test were examined in healthy male volunteers, in three single-dose studies. The studies consisted of two rising dose tolerance and kinetic studies with placebo control, each involving 14 volunteers, and an absolute bioavailability study involving 12 volunteers. The doses used in the rising dose studies were 0.5-20 mg intravenous pancopride in the first study, and 5-40 mg pancopride as oral solution in the second study. For the absolute bioavailability study, 20 mg doses as intravenous infusion, oral tablet and oral solution were compared. Pancopride was well tolerated at these doses in these studies. There were no significant effects on pulse rate, blood pressure, or electrocardiograms, or on haematology or serum biochemistry. Few adverse events were recorded, the most significant being gastrointestinal effects (including diarrhoea and soft stools) seen particularly with the 40 mg oral dose. Pharmacokinetic parameters for the 24 h after dosing were derived from plasma and urine pancopride levels, determined using a capillary gas chromatography-mass spectrometry method. Linear kinetics appeared to apply over the intravenous dose range 5-20 mg. Urinary recovery of unchanged pancopride was in the order of 10-17% over the 24 h after dosing.(ABSTRACT TRUNCATED AT 250 WORDS)