The heart rate response to succinylcholine in children: a comparison of atropine and glycopyrrolate.

To determine whether intravenous atropine and glycopyrrolate are equally effective in preventing succinylcholine-induced heart rate changes, we studied the heart rate during the first 78 seconds of anaesthesia in 40 children anaesthetized with either thiopentone, atropine (0.02 mg X kg-1) and succinylcholine (2 mg X kg-1), or thiopentone, glycopyrrolate (0.01 mg X kg-1) and succinylcholine (2 mg X kg-1). Each treatment group was divided into four subgroups which differed only in the interval (6, 10, 15, 20 seconds) between injection of atropine or glycopyrrolate and succinylcholine. During the 54 seconds after succinylcholine, the mean heart rate of each subgroup decreased transiently and then returned to the pre-induction heart rate or higher. There was no difference in either the magnitude or the duration of the decrease in heart rate or the subsequent increase in heart rate between respective subgroups. Bradycardia occurred in only two patients, both of whom received glycopyrrolate. We conclude that atropine (0.02 mg X kg-1) and glycopyrrolate (0.01 mg X kg-1) are equally effective in attenuating succinylcholine-induced changes in heart rate in children.