Effect of metformin on blood pressure in patients with hypertension: a randomized clinical trial

Part of the beneficial effects of metformin on the prevention of cardiovascular events in diabetes can be attributed to pleiotropic effects, including a blood pressure (BP)-lowering effect. In a double-blind parallel clinical trial (NCT02072382), the effect of metformin on BP evaluated by ambulatory blood pressure monitoring (ABPM) was measured.

Ninety-seven patients with hypertension, but without diabetes mellitus, were randomized to receive 850-1700 mg of metformin (n = 48) or placebo (n = 49). Clinical, laboratory, and ABPM data were collected at the baseline and after 8 weeks of follow-up.

The sample consisted mainly of White overweight women. There was no difference in BP reduction measured by ABPM between both groups. There was no effect in BP measured in the different periods of ABP monitoring and office BP. Additionally, fasting plasma glucose, lipids, and C-reactive protein remained unchanged during the trial. There was a significant reduction in waist circumference with metformin (95.1 ± 10.4 to 89.3 ± 27.4 cm; p = 0.02).

In the present trial, metformin did not reduce BP, measured by ABP monitoring, in hypertensive patients without diabetes.