The influence of urinary pH on flecainide excretion and its serum pharmacokinetics.

Abstract

The effect of urinary pH on flecainide excretion has been evaluated in six healthy subjects after a single oral dose of 300 mg flecainide administered as the acetate salt. The cumulative urinary excretion of unchanged flecainide under acidic conditions (134.0 +/‐ 16.1 mg; mean +/‐ s.e. mean) was significantly higher than under alkaline conditions (22.3 +/‐ 7.6 mg; mean +/‐ s.e. mean) (P less than 0.01). Under alkaline conditions, tmax (time to reach peak concentration) was reduced (P less than 0.01), while elimination half‐life, AUC(0‐32) and AUC(0‐infinity) were increased (P less than 0.01). 1984 The British Pharmacological Society