Reduced Diurnal Fluctuations in Carbamazepine Plasma Concentration by the Use of a Slow-Release Formulation

Abstract A slow-release formulation has been developed to overcome the problems of interdosage fluctuations in the plasma concentration of carbamazepine. In an open, comparative, within-patient trial, the daily plasma concentration profiles of this slow-release formulation were compared to the profiles of conventional carbamazepine tablets in 30 epileptic outpatients under continuous treatment with carbamazepine. Diurnal fluctuations in plasma levels of carbamazepine were significantly lower when conventional carbamazepine dosed b.i.d., t.i.d., or q.i.d. was replaced by slow-release carbamazepine dosed b.i.d. The bioavailability of the release formulation was about 20% less than that of conventional carbamazepine.