Urinary retention--an unusual dystonic reaction to continuous metoclopramide infusion.

Vomiting is one of the most distressing adverse effects of cancer chemotherapy. Metoclopramide by continuous infusion (400 micrograms/kg/h after a loading dose of 2.5 mg/kg) is a novel administration method for optimizing efficacy. A two-year-old boy developed urinary retention on three occasions, once accompanied by priapism and slurred speech, while receiving a continuous infusion. This was reversed by procyclidine, suggesting that it may have been a dystonic reaction.