Prazosin kinetics in essential hypertension.

Prazosin kinetics were studied in 8 hypertensive patients (4 male and 4 female) with normal renal function. Intravenous data showed a 3-phase distribution. As a result, a linear 3-compartment model with elimination from the central compartment was proposed to describe the drug kinetics. Prazosin disappeared from plasma with a terminal half-life t1/2 of about 3 hr and had a central distribution volume of about 0.18 1/kg. Only a negligible fraction of the dose was found unchanged in urine. The oral data showed that, of the 2-mg dose, about 1 mg was effectively absorbed. This fraction was almost entirely absorbed in 2 hr. Absorption kinetics were apparently linear with a t1/2 of about 30 min.