Comparison of once-daily guanfacine and twice-a-day methyldopa in the treatment of mild to moderate hypertension.

Control of hypertension (ie, reduction of blood pressure to less than or equal to 160/90 mmHg) in 40 mild to moderate hypertensives not responding adequately to hydrochlorothiazide was achieved by the addition of guanfacine (once daily) or methyldopa (twice daily) in a 16-week, double-blind, parallel-group trial. Control occurred after two weeks (at 1 mg/day) in 50% of the guanfacine-treated patients and in most patients within four to six weeks of treatment. The final mean doses were 2.5 mg/day of guanfacine or 763 mg/day of methyldopa. Sixteen patients maintained control of hypertension with continued guanfacine therapy for one year.