The pharmacokinetics of disopyramide in patients with acute myocardial infarction.

The effects of acute myocardial infarction on the pharmacokinetics of disopyramide were studied. Disopyramide (200 mg) was given orally to nine patients with left-sided cardiac failure due to acute myocardial infarction within 24 h after the onset (phase I). In seven patients the study was repeated 7-14 days later at discharge from the hospital (phase II). Serum concentrations and the 24-h area under the serum concentration-time curve of disopyramide were significantly lower during phase I than during phase II (p less than 0.05 and p less than 0.001, respectively). The peak serum concentrations and the 24-h area under the pulmonary capillary wedge pressure (less than 0.05) in phase I. Rates of absorption and elimination of disopyramide were similar during both phases. Renal clearance of disopyramide showed concentrations and the decrease of 24-h area under the serum concentration-time curve are most probably due to decreased gastrointestinal absorption and are related to the degree of left ventricular failure. Thus, the dosage of oral disopyramide obviously needs to be increased in these patients to achieve therapeutic concentrations in the acute phase.