[Inhibition of flecainide resorption by activated charcoal]

Abstract

The effect of orally administered activated charcoal on plasma concentrations of flecainide were studied in eight volunteers (24-38 years of age). A single dose of 200 mg flecainide were given at 3 days: control (day 1); simultaneous application of flecainide and 30 g charcoal (day 2); application of 30 g charcoal 90 min after flecainide (day 3). Plasma concentrations were determined by HPLC after 2, 4 and 6 h. Absorption of flecainide was almost completely prevented, when flecainide and charcoal was ingested immediately. When charcoal was taken 90 min after flecainide, the following flecainide plasma levels were found: after 2 h 231 +/- 62 ng/ml (266 +/- 30 ng/ml control; n.s.), after 4 h 199 +/- 49 ng/ml (232 +/- 27 ng/ml control; P less than 0.05) and after 6 h 155 +/- 42 ng/ml (231 +/- 51 ng/ml control; P less than 0.01). Charcoal seems to be effective in prevention of the absorption of flecainide. A drug interaction may occur if charcoal is given therapeutically, for example in hypercholesterolaemia. Charcoal may be indicated as an additional treatment of flecainide intoxication.