Effectiveness of prazosin as initial antihypertensive therapy.

After nearly 10 years in clinical use, prazosin has been shown in numerous studies worldwide to be an effective antihypertensive agent over the entire range of hypertension (mild, moderate, and severe), when used alone or in multitherapy. In addition to its general effectiveness, prazosin is particularly useful in specific subpopulations of hypertensive patients, such as those with impaired renal function, those on hemodialysis, and those with concomitant heart block, bronchospasm, diabetes mellitus, or disturbed carbohydrate metabolism, hyperlipidemia, or hyperuricemia. The side effects of prazosin are usually mild and transient and seldom require discontinuation of the drug. Sexual dysfunction is uncommon. In clinical experience with 22,000 patients receiving an initial dose of 1 mg of prazosin, syncope was reported in 1 of every 667 patients (0.15%). Withholding diuretics for 1 day before initiating prazosin therapy, utilizing prazosin as first-line therapy, limiting the initial dose to 1 mg, and taking it at bedtime are all helpful in eliminating many of the initial adverse effects. Fluid retention, although rare and not as pronounced as that with other antihypertensive agents, may develop on long-term therapy and may necessitate the addition of a diuretic later on.