Long-term treatment with transdermal clonidine in mild hypertension

Long-term antihypertensive treatment by once-weekly application of transdermal clonidine patches, in doses equivalent to 0.1, 0.2, 0.3 mg of clonidine daily, was evaluated in an open trial of 41 patients with baseline seated diastolic blood pressures of 90 to 103 mmHg. In all the patients, seated diastolic blood pressure was reduced to less than 90 mmHg with transdermal clonidine alone at the end of a dose titration phase of two to six weeks. Thirty-two patients successfully completed at least 22 months of therapy; three patients withdrew because of lack of efficacy and six because of adverse events. In the second treatment year 14 patients required a concomitant diuretic. Mean reductions in seated diastolic blood pressure from baseline values were statistically significant (P less than 0.0001) at all study intervals. The incidence of patient withdrawals resulting from the development of contact dermatitis at the patch application site was 5%; skin irritation not requiring withdrawal occurred in 13 patients during the first year of treatment and in two during the second. The incidence of dry mouth (in 7%) and drowsiness (in 10%) was lower than has been reported during oral clonidine therapy (40% and 35%). The results suggest that transdermal clonidine may be beneficial for the maintenance therapy of many patients with mild hypertension.