One year efficacy and tolerability of clonidine administered by the transdermal route in patients with mild to moderate essential hypertension--a multicentre open label study. The Antihypertensive Patch Italian Study (APIS) Investigators.

The clonidine patch offers for the first time the unique possibility of a once-a-week transdermal therapy of hypertension due to direct absorption of clonidine through the skin. The present study investigates the efficacy and safety of the transdermal administration on a sample of the Italian population. 101 patients entered the study, 51 male, 50 female (mean age: 53 years, SD +/- 10; range: 30-71 years), they were given clonidine by a therapeutical transdermal system as starting dosage. If blood pressure was not adequately controlled (DBP < 90 or 10 mmHg decreased from baseline value) the dosage was increased on a 2 week basis assessment. The patients were then followed for 12 months after the start of treatment. The decrease in both systolic and diastolic blood pressure continued up to one month after start of treatment and remained constant for at least 9 months. A total of 70% of the patients were controlled by the antihypertensive treatment as monotherapy, while in 6% additional combination with a diuretic lead to blood pressure control. 5% of the patients showed no reduction in blood pressure at the end of the titration phase. 24 (23%) patients complained of skin reaction; 21 patients of these (ten male, eleven female) were withdrawn from the trial due to predefined skin reaction criteria. No serious side effects have been observed during the run of the study. No rebound phenomena occurred in the week after treatment discontinuation. It is concluded that the transdermal treatment of hypertension with a clonidine containing transdermal system is therapeutically effective and probably associated with a high acceptability and increased compliance.