Digitalis Intoxication

The symtoms of digitalis intoxication were clearly described by Withering in 1785,1and are due to the action of the drug on the gastrointestinal, central nervous, and musculoskeletal systems, and on the heart. As a rule, however, it is the effect of the drug on the heart (cardiotoxic effect) that may be life threatening, and for this reason our discussion will be confined to cardiotoxic effects. The incidence of digitalis intoxication has been on the increase ever since the introdution of purified, highly potent glycosides, with frequency of cardiotoxic reactions in hospitalized patients receiving digitalis given as 12% to 20%.2 Factors Contributing to Cardiotoxic Reactions Some of the pharmacological properties of digitalis contribute to the relatively high incidence of cardiotoxic reactions. In the first place, the margin of safety between the therapeutic and toxic, and the toxic and lethal dose is relatively narrow. It has been estimated that