A dose-titration trial of guanadrel as step-two therapy in essential hypertension.

The efficacy and safety of low-dose guanadrel sulfate were evaluated in 20 patients with essential hypertension based on seated diastolic blood pressures (SDBP) ranging from 95 to 115 mm Hg despite a trial dosage of hydrochlorothiazide 50 mg/d for up to five weeks. These patients had been resistant to, or intolerant of, one or more step-two antihypertensive drugs in the past (i.e., methyldopa, beta-adrenergic blocking agents, clonidine, or prazosin). The majority of patients demonstrated a satisfactory response (SDBP 95 mm Hg or reduction in SDBP of 10 mm Hg) to guanadrel. Nine patients responded at a low dosage, 10 to 20 mg/d and remained free from adverse effects throughout the study (up to 12 weeks of treatment). Of the remaining 11 patients titrated to higher dosages of guanadrel (30 to 60 mg/d), three had no discernible response while six developed adverse effects. The results of the study suggest that guanadrel has an acceptable benefit-to-risk ratio only when used in low dosages (10 to 30 mg/d) and may be successfully employed as step-two antihypertensive therapy in patients resistant to, or intolerant of, other step-two agents.