The antiemetic profile of zacopride.

The antiemetic activity of zacopride against a variety of emetogenic agents has been determined in dogs. Zacopride was highly effective in inhibiting emesis due to a wide range of cancer chemotherapeutic agents, particularly cisplatin. It was well absorbed orally since the dose of zacopride required to inhibit cisplatin-induced emesis in dogs by 90% was 28 micrograms kg-1 both by i.v. and p.o. routes. Further, zacopride (1 mg kg-1 p.o.), administered after the onset of cisplatin-induced emesis, reduced the number of subsequent emetic episodes by 91%. Zacopride at 0.1, 1, or 3.16 mg kg-1 p.o. or i.v., reduced the number of emetic episodes due to dacarbazine, mechlorethamine, adriamycin, actinomycin D, or peptide YY by 100, 100, 86, 96 and 79%, respectively. However, zacopride was not effective in inhibiting emesis due to either apomorphine, copper sulphate, protoveratrine A, histamine, or pilocarpine. No adverse effects attributed to zacopride were observed. Zacopride is thus a unique and potent antiemetic agent as it selectively inhibits the emetic response to cancer chemotherapy agents and peptide YY.