EVALUATION OF CURARIZING DRUGS IN MAN

III. Antagonism to Curarizing Effects of D-Tubocurarine and Decamethylene-Bis(Trimethylammonium Bromide)

¹ Departments of Pharmacology and Surgery (Anesthesia), University of Illinois, College of Medicine, Chicago 12, Illinois

Antagonism of neostigmine and C5 to the curarizing action of dTC and C10 was studied in unanesthetized man and on mice. In all experiments, administration of the potential antagonist preceded that of the curarizing agent.

1. Neostigmine (0.75 mgm.) significantly reduced but did not abolish the paralyzing effects of dTC. It also shortened the duration of action of dTC. In mice, it increased significantly both the HD₅₀ and the LD₅₀ of dTC.

2. C5 (50 mgm.) failed to alter significantly the effects of C10 on grip strength and vital capacity in man. The duration of action of C10 remained unchanged. C5 also failed to antagonize the paralyzing effects of C10 in mice as measured by the HD₅₀.

3. C10 in large doses caused excitement in mice. C5 and sodium thiopental were equally effective in increasing the LD₅₀ of C10. This effect of C5 was apparently independent of its ganglionic blocking action, since other blocking agents like TEA failed to exert such an effect.

4. Curarization with dTC almost completely abolished the response to a subsequent injection of C10 in unanesthetized subjects and in patients during surgical anesthesia.