Allopurinol to influence blood pressure in hypertension patients: systematic review and meta-analysis

The increase of serum uric acid (UA) is considered to be associated with the development and progress of hypertension, and the influence of allopurinol, a UA-lowering agent, on patients with hypertension is still unclear. This study aimed to sysmatically evaluate the influence of allopurinol on the blood pressure (BP) in patients with hypertension as well as its safety. Computer retrieval of PubMed, EMbase and Cochrane library as well as WEB SCINENCE was performed for randomized controlled trials (RCTs) pertinent to the effect of allopurinol on the BP of patients with hypertension, with no language restraint for the studies. The changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were used as the primary endpoints, and the changes in serum UA and the incidence of adverse reactions as the secondary endpoints. A total of six RCTs along with 419 patients were included, with a follow-up of 6.67 +/- 3.27 weeks. Compared with the control group, a significant decrease was observed in allopurinol group in SBP (mean difference [MD] = 5.42, 95% confidence interval [CI] = 3.99-6.85, P < 0.001), DBP [MD = 4.07, 95% CI = -2.84-5.30, P < 0.001) and serum uric acid (MD = 2.05, 95% CI = 1.32-2.78, P < 0.001). Subgroup analysis also revealed a remarkably lowered SBP and DBP in adults (>18 years) and adolescents (< 18 years) of allopurinol group in relative to the control group. Low-(<= 300 mg/d) or high-(> 300 mg/d) dose allopurinol were associated with a significant reduction in SBP. Low-dose allopurinol (< 300 mg/day) was more effective at reducing DBP than high-dose (> 300 mg/day). Indeed, allopurinol can lower the BP in patients with hypertension.