Guanabenz versus methyldopa in the therapy of mild-to-moderate hypertension

The results of a double-blind cross-over study designed to evaluate the antihypertensive efficacy and safety of guanabenz versus methyldopa in mild-to-moderate essential hypertension are presented. Thirty patients were randomly assigned to a group receiving either guanabenz or methyldopa as initial therapy for 8 weeks, followed by a 2-week wash-out period; the patients then took the other trial medication for 8 weeks. There was a significant fall in both standing and supine systolic and diastolic blood pressures during each treatment period, but no statistically significant difference between the guanabenz and methyldopa periods. However, there was a significant difference between the two drugs as regards side-effects. In the guanabenz group 21% of patients stopped taking the drug because of side-effects or inefficacy compared with none of the patients in the methyldopa group. The overall incidence of adverse experiences was 76% for guanabenz and 50% for methyldopa. There was a statistically significantly greater incidence of dry mouth with guanabenz then with methyldopa, while drowsiness was common in both groups. It is concluded that guanabenz is as effective as methyldopa in the therapy of mild-to-moderate essential hypertension but that the side-effects, particularly dry mouth, will seriously limit its usefulness.