Relative Bioavailability of Prazosin Hydrochloride Tablet in Man

Abstract

Plasma level, urinary excretion rate, decrease in arterial pressure, and increase in heart rate were measured after oral ingestion of prazosin (2mg) by six healthy adults, in either tablet form or in aqueous solution, in order to evaluate the relative bioavailability of the tablet. The amount of absorption was proven to be the same for both, but the maximal plasma level after ingestion was significantly higher with the aqueous solution. The diastolic arterial pressure was found to be decreased significantly with both dosage forms soon after ingestion, but starting a little later than the appearance of the maximal plasma level and continuing for at least six hours. This effect was not affected by the form of dosage. The same result was found with regard to the effect of increase in the heart rate. It was concluded that the prazosin tablet is effective and becomes fully bioavailable after a single oral ingestion of a 2 mg tablet.