Effect of allopurinol on blood pressure: a systematic review and meta-analysis.

Allopurinol is a potent xanthine oxidase inhibitor that is used in hyperuricemic patients to prevent gout. It has also been shown to decrease cardiovascular complications in a myriad of cardiovascular conditions. However, studies have reported conflicting evidence on its effects on blood pressure (BP). A systematic review was conducted using Medline, PubMed, Embase, and the Cochrane Library for all the longitudinal studies that assessed the efficacy of allopurinol on systolic and diastolic BP. A total of 10 clinical studies with 738 participants were included in the analysis. Compared with the control group, systolic BP decreased by 3.3 mm Hg (95% confidence interval [CI], 1.4-5.3 mm Hg; P=.001) and diastolic BP decreased by 1.3 mm Hg (95% CI, 0.1-2.5 mm Hg; P=.03) in patients treated with allopurinol. When analysis was restricted to the higher-quality randomized controlled trials, similar changes in systolic and diastolic BPs were found: 3.3 mm Hg (95% CI, 0.8-5.8 mm Hg; P<.001) and 1.4 mm Hg (95% CI, 0.1-2.7 mm Hg; P=.04), respectively. Allopurinol is associated with a small but significant reduction in BP. This effect can be potentially exploited to aid in controlling BP in hypertensive patients with hyperuricemia.