Effect of repeated succinylcholine injections on heart rate following intramuscularly administered antimuscarinic drugs: glycopyrrolate and atropine.

The possibility of using the longer acting antimuscarinic drug glycopyrrolate intramuscularly to prevent the bradycardia that sometimes results from successive doses of succinylcholine was examined. Atropine, in an equipotent dose, was given to another group of patients for comparison. Glycopyrrolate was as ineffective as atropine in preventing bradycardia. Later, a third group of patients who received no antimuscarinic drug was studied as controls. This last group had no more bradycardia than the other two groups.