Could a uric acid–lowering drug reduce blood pressure in teens with newly diagnosed hypertension?

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High uric acid levels predict the development of hypertension and are common in newly diagnosed essential hypertension. In animal models, experimentally raising uric acid with a uricase inhibitor causes systemic hypertension. The researchers asked whether lowering uric acid would lower blood pressure in adolescents with high uric acid and newly diagnosed hypertension.

From September 2004 to March 2007, a randomized, double-blind, placebo-controlled crossover trial enrolled 30 adolescents aged 11–17 with newly diagnosed, never-treated stage 1 essential hypertension and serum uric acid of at least 6 mg/dL. They were treated at the Pediatric Hypertension Clinic at Texas Children's Hospital in Houston. Those with stage 2 hypertension or known kidney, cardiovascular, gastrointestinal tract, liver, or endocrine disease were excluded.

Participants received allopurinol 200 mg twice daily for 4 weeks and placebo twice daily for 4 weeks, separated by a 2-week washout. Treatment order was randomized. The main outcomes were changes in casual and ambulatory blood pressure.

For casual systolic blood pressure, the mean change was −6.9 mm Hg with allopurinol (95% confidence interval [CI], −4.5 to −9.3) versus −2.0 mm Hg with placebo (95% CI, 0.3 to −4.3; P = .009). For casual diastolic pressure, it was −5.1 mm Hg with allopurinol (95% CI, −2.5 to −7.8) versus −2.4 mm Hg with placebo (95% CI, 0.2 to −4.1; P = .05).

For mean 24-hour ambulatory systolic pressure, the mean change was −6.3 mm Hg with allopurinol (95% CI, −3.8 to −8.9) versus 0.8 mm Hg with placebo (95% CI, 3.4 to −2.9; P = .001). For mean 24-hour ambulatory diastolic pressure, it was −4.6 mm Hg with allopurinol (95% CI, −2.4 to −6.8) versus −0.3 mm Hg with placebo (95% CI, 2.3 to −2.1; P = .004).

Twenty of 30 participants reached normal blood pressure by both casual and ambulatory criteria while taking allopurinol, versus 1 participant while taking placebo (P < .001). In this short-term crossover study, allopurinol treatment reduced blood pressure in adolescents with newly diagnosed hypertension. The researchers described this as a potential new therapeutic approach, but not a fully developed treatment strategy because of possible adverse effects. These preliminary findings need confirmation in larger clinical trials. The trial was registered at ClinicalTrials.gov as NCT00288184.