Essential Hypertension is Reduced with Transdermal Clonidine

Transdermal administration of clonidine was studied in 20 patients (aged 26-68 years) who had essential hypertension (diastolic BPs of 91-105mm Hg). Skin patches (3.5 cm2) were impregnated with either clonidine or placebo and applied to either the upper anterior chest or the anterior surface of the shoulder or upper arm. A new patch was used each week. Following a 2-week placebo period, patients entered a dose titration period - if BP became normal after a week using 1 patch, patients continued such treatment for a further 3 months. If BP remained abnormal they applied 2 patches in a 2nd titration week, and if required, 3 patches in a 3rd titration week, then continued treatment for 3 months at the required dose. Those patients whose BP

still remained abnormal were dropped from the study. Placebo was substituted for clonidine for a week following the 3-month treatment period.

Twelve of the patients took part in the titration section of the study - 1 patient used 1 patch, 5 used 2 patches, 6 used 3 patches. Mean systolic BP for all patients (including the non-responders) was reduced from 138.3 to 134mm Hg, and diastolic BP was reduced from 96.9 to 90.8mm Hg. At the end of dose titration, responders showed average BPs of 129.6mm Hg (systolic) and 87.1 mm Hg (diastolic).

In the second placebo period, BP rose to pretreatment levels and was significantly higher than during the maximum response to treatment.

Dry mouth was reported by 6 patients and slight drowsiness by 3. These usually lasted for no longer than a week and no patient withdrew from treatment due to side effects.

In this study, transdermal clonidine produced similar results to those expected with oral clonidine. Weber. M.A. et al.: Lancet 1: 9 (7 Jan 1984)

0156-2703/84/0204-0007/0$01.00/0 © AOIS Press INPHARMA® 4 Feb 1984 7