Terazosin: pharmacokinetics and the effect of age and dose on the incidence of adverse events.

Terazosin is a new, long-acting, selective, postsynaptic alpha 1-adrenergic receptor antagonist with a chemical structure similar to that of prazosin. In this article the pharmacokinetics of terazosin are reviewed, and the incidence of adverse events in a dose-response study and a meta-analysis of 20 placebo-controlled trials involving a total of 1814 patients is presented. Peak plasma concentrations of terazosin are achieved 1 to 2 hours after oral administration. The relatively long half-life of terazosin (12 hours) enables it to be administered in a once-a-day regimen. Dose and plasma levels of terazosin show a linear relationship. Terazosin is rapidly and completely absorbed after oral administration. The pharmacokinetics of terazosin are not significantly affected by food, age, hypertension, or renal impairment. Adverse events after the administration of terazosin are usually minor and not age related. The incidence of syncope after therapeutic dosages of terazosin is minimal. Terazosin's effectiveness, combined with its pharmacokinetics, safety profile, and potentially favorable lipid effect, makes it a highly appropriate choice for antihypertensive therapy.