Stability of plasma amiodarone levels during chronic oral therapy.

The variability of plasma amiodarone levels in 51 patients receiving chronic oral therapy over 4-53 (median 19) months was examined; 3-14 (median 5) plasma samples were obtained. After a loading dose, most patients received either 200 mg or 400 mg a day. Mean plasma amiodarone concentration was 1.2 +/- 0.6 mg/l and mean plasma desethylamiodarone concentration was 1.2 +/- 0.5 mg/l. No relationship was seen between height and weight and plasma concentrations. Dose was a significant predictor of plasma level (p less than 0.01) although it was a poor predictor of steady state amiodarone concentration.