Plasma levels of ethaverine after oral administration to humans.

Fourteen healthy human subjects received a 200 mg oral dose of ethaverine hydrochloride as an elixir. Blood samples were obtained for 12 h after dosing. Plasma ethaverine concentrations were determined using a paired-ion, reversed-phase high performance liquid chromatographic method. Individual plasma concentration-time profiles were fitted to a two-compartment model with first-order absorption. The ethaverine was rapidly absorbed, based on a time of maximum plasma concentration of 0.75 h, a time-lag of 8.4 min, and an apparent first-order absorption half-life of 8.6 min. The mean terminal elimination half-life was 3.3 h.