Clinical pharmacokinetics of high-dose metoclopramide in cancer patients receiving cisplatin therapy.

Using a sensitive and specific high-pressure liquid chromatographic (HPLC) assay, we measured serum levels of metoclopramide in 18 cancer patients receiving high-dose intravenous (IV) therapy to prevent cisplatin-induced emesis. Ten patients were treated with one or more courses with metoclopramide alone (1.0 to 3.0 mg/kg) in an open-label study, and eight patients were treated with a fixed 2.0 mg/kg dose of metoclopramide with or without adjunct dexamethasone (20 mg) using a randomized, crossover design. The pharmacokinetics of metoclopramide were determined, and the relationship between serum levels and clinical response was evaluated. The pharmacokinetic parameters of high-dose metoclopramide were found to be similar to those reported for standard promotility doses, and no dose dependency was demonstrated over the range of doses studied. No clear correlation between serum metoclopramide levels and prevention of cisplatin-induced emesis was observed. The addition of dexamethasone resulted in clinical improvement in two of eight patients, but had no effect on serum metoclopramide levels or kinetic parameters. Results in this study population do not show metoclopramide levels to be related to antiemetic effect following IV cisplatin therapy.