guanfacine , 1 to 3 mg/day , and clonidine , 0.1 to 0.3 mg twice a day , were compared in a 24-week double-blind , randomized , parallel study of 42 patients with hypertension that was inadequately treated by chlorthalidone , 25 mg/day .
C0009014
clonidine
C0020538
hypertension