Transdermal clonidine therapy and blood pressure nocturnal fall in mild hypertensive male subjects

Treatment of mild hypertension with an antihypertensive drug administered by means of a transdermal therapeutic system (TTS) could produce favorable results, when compared with a traditional oral regimen.

Using 24-h ambulatory blood pressure (BP) monitoring (ABPM) in mild hypertensive male subjects, to analyze three aspects which have not been completely clarified: a) whether a latency in the antihypertensive effect may be present, recording BP already from the first day of application of the patch, b) the eventual hazardous enhancement of circadian nocturnal fall in BP values in treated mild hypertensive patients and, c) the possible overlapping of antihypertensive effect between the administration of two consecutive patches.

In 12 caucasian male outpatients (yrs 55 +/- 3 SEM) with uncomplicated essential mild hypertension, a patch containing placebo was applied for the first week (T 0 period). At the end of the T 0 period, a 5 mg TTS-2 clonidine patch was applied for one week, and, subsequently, a new patch of 5 mg TTS-2 clonidine was kept for another week. ABPM was performed on the last day of the placebo period (T 0) and on the 1st day (T1), the 7th day (T2) and the 14th day (T3) of transdermal clonidine therapy.

Both systolic and diastolic BP (24 h mean, day-night-time) decreased on the 1st, 7th and 14th day, when compared with T0. However, no significant differences were documented between the BP levels on the 1st and the 7th day of treatment. The incidence of nocturnal fall in systolic and diastolic BP was evaluated and no significant differences were found, when compared with night-time reference values.

When compared with the placebo period, TTS-2 clonidine lowers SBP and DBP within the first 24 hours of application. The antihypertensive effect persists at the end of the first week, as well as after 14 days. The lowest values of systolic-diastolic BP documented were not below the levels reported in normotensive men. Therefore, TTS-2 clonidine seems to act as an antihypertensive agent rather than a hypotensive drug since it normalizes BP without lowering it below physiological levels.