Efficacy and safety of two different galenic formulations of a transdermal clonidine system in the treatment of hypertension.

The efficacy and safety of two different galenic formulations of transdermal clonidine systems were compared in 905 patients with mild to moderate essential hypertension during a 12 weeks observation period. 449 patients were treated with the matrix controlled clonidine transdermal (C-TD) system and 456 patients with the membrane controlled clonidine system (C-TTS). The mean blood pressure was reduced from 168/102 mmHg to 146/87 mmHg in the C-TD and from 169/102 mmHg to 148/88 mmHg in the C-TTS group. There was no difference in the response rate. The pattern of systemic side-effects appeared to correspond to those seen during oral clonidine treatment but with a lower frequency and intensity. The C-TD patch improved skin tolerability and the drop-out rate due to skin reactions was 2.2 times lower compared with the C-TTS group. Local skin reactions led to withdrawal in 35 of 449 C-TD treated and in 79 of 456 C-TTS treated patients. In conclusion, the improved carrier system for the transdermal clonidine treatment reduced local side-effects which in turn may further enhance acceptability and compliance in treated patients.