Studies of Plasma Quinidine Content

Abstract

The plasma quinidine curves obtained by the oral and intramuscular routes of administration of 0.6 Gm. quinidine sulfate and 0.65 Gm. quinidine lactate, respectively, were generally similar. Maximal concentration, averaging 3.2 mg. per liter in the former group occurred from one-half hour to four hours after administration, and in the latter averaged 2.6 mg. per liter in one to three hours. Significant quantity of quinidine remained at eight hours, and small amounts at twenty-four hours. Rectal administration of 0.6 Gm. quinidine sulfate resulted in lower concentrations, the maximum averaging 0.89 mg. per liter. The chief value of intramuscular quinidine therapy appears to be the avoidance of gastrointestinal irritation, but hypotensive reactions were relatively frequent in the small series of patients studied.