Continuous infusion of metoclopramide was compared with bolus dosing in a randomized, double-blind study in 27 patients receiving cisplatin therapy. Hospitalized patients receiving their first course of cisplatin (120 mg/sq m administered i.v. over four hours) were randomized to receive either bolus doses or a continuous infusion of metoclopramide. In the infusion group (14 patients), a loading dose of metoclopramide 3 mg/kg (total body weight) as the hydrochloride salt was infused over one hour immediately before the administration of cisplatin, followed by a continuous infusion of metoclopramide 0.5 mg/kg/hr (as the hydrochloride salt) for 12 hours. Each patient received a total metoclopramide dose of 9 mg/kg over 13 hours. These patients also received five bolus doses of 5% dextrose injection (as placebo) over 15 minutes, with the first dose given one hour before the cisplatin and four more doses at two-hour intervals. In the bolus-dose group (13 patients), metoclopramide 2 mg/kg as the hydrochloride salt was added to each of the bolus doses, while the continuous infusion was a placebo of 5% dextrose injection. All patients also received dexamethasone 10 mg i.v. and diphenhydramine hydrochloride 50 mg i.v. Patients were monitored for 24 hours after initiation of metoclopramide administration for number of emesis episodes and for adverse effects. In the infusion group, 11 of 14 (79%) patients had two or fewer episodes of emesis. In the bolus group, 10 of 13 (77%) had two or fewer vomiting episodes. Mild sedation occurred in both the infusion (79%) and bolus-dose (77%) groups. Despite the use of diphenhydramine, extrapyramidal reactions were seen in one bolus-dose patient and two infusion patients.(ABSTRACT TRUNCATED AT 250 WORDS)