Clinical pharmacology of vecuronium in children. Studies during nitrous oxide and halothane in oxygen anaesthesia.

Forty-seven children (ASA I or II) were studied during nitrous oxide-oxygen, halothane anaesthesia. The dose-response curve for vecuronium was determined after the injection of a single bolus (40, 55 or 70 micrograms kg-1) to 33 patients. The ED50 and ED95 were 31 and 64 micrograms kg-1 respectively. Fourteen children received a larger dose (100 micrograms kg-1); good intubating conditions were obtained in all of these within 2 min. After a single bolus (100 micrograms kg-1) the duration of action was 36.5 min and the recovery index was 9.3 min. In patients who received small maintenance doses (25 micrograms kg-1) after a single bolus (100 micrograms kg-1) the recovery index after the last maintenance dose was not increased. There were no significant changes in heart rate or arterial pressure. In children, vecuronium has a short duration of action and lacks cumulative or cardiovascular side affects.