Effect of serum urate lowering with allopurinol on blood pressure in young adults: A randomized, controlled, crossover trial.

OBJECTIVE To determine whether serum urate reduction with allopurinol lowers blood pressure (BP) in young adults and the mechanisms mediating this hypothesized effect. METHODS Single-center, double-blind, randomized, crossover clinical trial. Adults ages 18-40 with baseline systolic BP (SBP) ≥ 120 and < 160 mm Hg or diastolic BP (DBP) ≥ 80 and < 100 mm Hg, and serum urate ≥ 5.0 mg/dL for men or ≥ 4.0 mg/dL for women were enrolled. Main exclusion criteria included chronic kidney disease, gout, or past use of urate-lowering therapies. Participants received oral allopurinol (300 mg daily) or placebo for one month followed by a 2-4 week washout and then were crossed over. Study outcomes were change in SBP from baseline, endothelial function estimated as flow-mediated dilation (FMD), and high-sensitivity C-reactive protein (hs-CRP) levels. Assessments of adverse effects were conducted. RESULTS 99 participants were randomized and 82 completed all visits. Mean age was 28.0 ± 7.0 years, 62.6% were men, and 40.4% were African-American. In the primary intention-to-treat analysis, SBP did not change during the allopurinol (-1.39 ± 1.16 mm Hg [mean ± standard error mean]) or placebo (-1.06 ± 1.08 mm Hg) treatment periods. FMD increased during allopurinol treatment periods compared to placebo (2.5% ± 0.55% versus -0.1% ± 0.42%, p<0.001). There were no changes in hs-CRP and no serious adverse events. CONCLUSIONS Urate-lowering therapy with allopurinol in young adults did not lower SBP or hs-CRP when compared with placebo, despite improvements in FMD. These findings do not support urate-lowering as a treatment for hypertension in young adults.