Tocainide kinetics after intravenous and oral administration in healthy subjects and in patients with acute myocardial infarction

Tocainide is structurally related to lidocaine but may be used orally as well as intravenously. A therapeutic plasma concentration range of 25 to 45 mumole/l has been suggested. Tocainide kinetics were studied in 6 healthy subjects and 16 patients with acute myocardial infarction. There was good accordance in kinetics of healthy subjects and patients. After intravenous administration the mean t1/2 was about 14 hr, volume of distribution about 3.0 l/kg, and corrected renal clearance about 140 ml/min. An average of 35% of the dose was recovered unchanged in urine. After oral administration the absorption rate was rapid relative to the elimination rate, extent of bioavailability was complete, and the apparent volume of distribution was the same as that after intravenous injection. A dose regimen of 750 mg intravenously directly followed by 800 mg orally and subsequently 400 mg 3 times daily resulted in therapeutic plasma levels within 15 min. The plasma levels remained within the therapeutic range throughout a period of observation from 48 to 168 hr.