Canadian Journal of Anesthesia, Vol 15, 111-117, Copyright © 1968 by Canadian Anesthesiologists' Society

The Interaction of Drugs, With Particular Reference to Anaesthetic Practice

¹ Division of Anaesthesiology, Department of Surgery, and Department of Pharmacology, Faculty of Medicine, University of British Columbia

The effects of drug combinations have certain characteristic properties produced by the interaction of the physiological-pharmacological effects of the constituents. The results may be:

1. Inapparent. Potential interaction between drugs may be of little significance or even quite inapparent, if the side-effects are opposite in nature and equal in strength.

2. Antagonistic. Some types of antagonism may be dangerous, or they may be merely inconvenient.

3. Synergistic. Synergistic action of drugs may result from (a) summated actions, and/or (b) potentiated actions which may be desirable if unwanted side-effects of each component can be "filtered out," but undesirable if unforeseen exaggeration of the desired effect occurs.

With greater awareness and understanding of the underlying mechanisms, the many untoward interactions now being increasingly reported might be foreseen and avoided.

Note:

Presented at the Annual Meeting of the Canadian Anaesthetists' Society, Montreal, June 1967.