Plasma levels of disopyramide after administration of conventional capsules and sustained-release tablets.

SummaryA study was carried out in 33 patients with myocardial infarction and complicating arrhythmias to compare plasma levels of disopyramide attained after administration of conventional capsules or sustained-release tablets. On Day 1, 29 patients started treatment with 600 mg disopyramide in 3 divided doses of conventional capsules. In 18, disopyramide plasma concentrations of 3 mg/l or more were achieved within 300 minutes after the first dose. On the second day, patients were allocated at random to receive treatment double-blind for 11 days with 500 mg disopyramide daily given either as conventional capsules (17 patients) or as sustained-release tablets (16 patients). Plasma concentrations were measured just before and 3 hours after the morning dose. Mean maximum and minimum concentrations in the conventional capsule group were 4.4 mg/l and 2.8 mg/l, respectively, compared to 4.3 mg/l and 3.0 mg/l, respectively, in the sustained-release tablet group. For the next 30 days all patients continued treatm...