Clinical toxicology of cardiovascular drugs

Drugs used to treat cardiovascular diseases have low therapeutic indices, may produce the very pathophysiologic effects that it is hoped they will reverse, and are used commonly in aged animals with multisystemic diseases for which they are receiving other compounds. These factors predispose to undesirable drug reactions and interactions. It is difficult to determine, a priori, which animals will respond with profound toxic manifestations; therefore, resuscitative measures, including drugs and devices, must be available at all times, and the clinician must be schooled in their use. In particular, class IA antiarrhythmics, digitalis glycosides, and antineoplastic compounds, all used relatively frequently, have great potential for producing toxicosis. An important role of the clinician with regard to cardiovascular toxicology lies in providing consultation to both the pharmaceutical industry and governmental regulatory agencies. Because the worst aspects of cardiovascular toxicosis lie in electrical disturbances of the heart, and because electrocardiography is the best method for studying these electrical properties, the clinician and adviser to the pharmaceutical industry and the FDA must be well schooled in electrocardiography.