Clonidine in mild to moderate hypertension: effects on blood pressure and serum lipoproteins.

Fifty-nine patients with primary hypertension, WHO stages I and II, participated in a 6-month multicentre, single-blind study to evaluate the effects of small doses of clonidine (75-300 micrograms daily) on blood pressure (BP) and serum lipoproteins. The investigation started with a dose-titration period. The mean BP values when the patients were receiving placebo were 166/104 +/- 14/5 (s.d.) mmHg supine and 162/106 +/- 14/6 mmHg standing. The mean BP values at the end of the study were 151/92 +/- 13/6 mmHg supine and 144/95 +/- 11/6 mmHg standing. A diastolic BP of less than 95 mmHg was achieved in 34 patients with a dose of less than 150 micrograms clonindine daily. Eight patients required a higher dose to achieve this level and in 10 a thiazide diuretic was added. The mean daily dose for the whole series was 148 micrograms clonindine/day. Serum lipoproteins were determined by ultracentrifugation in 23 previously untreated patients with hypertension. Serum cholesterol increased by 6% and a small decrease in low density lipoprotein-serum triglycerides (LDL-TG) was registered. No other significant changes were observed during clonidine treatment compared with placebo in the very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL). Adverse side effects were mild and tolerable, and consisted mostly of dryness of the mouth and fatigue. mouth and fatigue. It is concluded that clonidine in small doses significantly lowers the BP with no adverse effect on serum lipoproteins.