Glycopyrrolate methobromide: 2. comparison with atropine sulphate in anaesthesia

A double blind study of 98 patients was undertaken to compare the clinical usefulness of atropine and glycopyrrolate for pre-anaesthetic medication and their relative effectiveness in antagonizing the muscarinic effects of neostigmine methylsulphate given to reverse neuromuscular blockade. Intramuscular administration of atropine 0.4 mg or of glycopyrrolate 0.2 mg produced the same degree of dryness of the pharynx. However, glycopyrrolate was found to be a more potent antagonizer of the increased salivation induced by neostigmine. By intramuscular administration, both drugs produced the same degree of tachycardia, although atropine tended to cause no change in the pulse rate or even to produce bradycardia in a greater number of patients. Administered intravenously, atropine produced a more significant tachycardia in a large number of patients prior to neostigmine administration, although the protection against a decreased pulse rate from neostigmine is greater in those patients who received glycopyrrolate. It would appear, therefore, that glycopyrrolate is more effective in antagonizing the muscarinic effects of neostigmine methylsulphate.