A new centrally action antihypertensive agent guanfacine (BS 100-141).

In 21 patients with essential hypertension, all of whom completed the study, marked reductions in systolic and diastolic blood pressure were achieved under therapy withN-amidino-2-(2,6-dichlorophenyl)-acetamide hydrochloride (guanfacine, BS 100-141) administered 3 times daily in small to medium, gradually increasing doses. The lowest daily dose was 1 mg, the highest 10 mg, the average being 4 mg. Despite the low initial dosage and subsequent slow progression--designed to keep side effects within limits--BS 100-141 had a rapid and significant antihypertensive effect on both systolic and diastolic blood pressure. Habituation, with consequent loss of effect, was not observed. Laboratory parameters did not change, although blood sugar was reported to have shown a general tendency to rise in the study. Renal function and electrolytes remained normal. This new anithypertensive should probably be classified, as regards efficacy, alongside clonidine and methyldopa; it would also seem to be about as well tolerated as these two compounds. In order to prevent side effects, a gradually increasing low-dose regimen is recommended.