The Effect of Small Dose of Glycopyrrolate on the Heart Rate in the Anesthetized, and Comatose Patient

Abstract

Glycopyrrolate (Robinul) is a potent anticholinergic drug. Being a quantenary ammonium compound, it does not cross the blood-brain barrier and thus does not have the central effects. It has been shown that glycopyrrolate has a pharmacologic properties similar to that of atropine, belladonna alkaloid, but it has lesser effect on the heart rate than that of atropine. The authors administered a small does of glycopyrrolate intravenously to 18 people whowere awake, 21 comatous cases and 17 halothane anesthetized cases. The effect on the heart rate in these 3 groups was compared. The results are as follows; 1) In the awake state, glycopyrrolate (0.1 mg) produced a slight decrease in the heart rate. 2) In the comatose state, glycopyrrolate (0.1 mg) produced a slight increase in the heart rate. 3) In the halothane anesthetized state, glycopyrrolate (0.1 mg) produced a significant increase in the heart rate. 4) In the comatose state, the absence of bradycardia after a small dose of glycopyrrolate is similar to a small dose of atropine. Therefore we suggest that bradycardia after glycopyrrolate and atropine is caused by sympathetic ganglion block.