In a nutshell
This study examined the effect of allopurinol on blood pressure in hyperuricemic adolescents with newly diagnosed hypertension.
Some background
Allopurinol is a drug that inhibits xanthine oxidase (an enzyme that plays a major role in the formation of uric acid), reducing uric acid production and consequently lowering its blood levels. This study evaluated whether lowering uric acid blood levels (with allopurinol) in adolescents with hypertension subsequently lowered blood pressure.
Methods & findings
30 adolescents (11 – 17 years) with newly diagnosed hypertension and blood uric acid levels of 6.0 mg/dL or higher were randomly assigned into 2 groups. The first group was treated with allopurinol twice daily for 4 weeks while the second group was treated with a placebo (a substance that has no therapeutic effect) twice daily for 4 weeks (control group). Following this the patients underwent a 2 week washout period (no drugs were administered) and then a crossover phase for 4 weeks (patients who had previously taken placebo were administered allopurinol and vice versa). Patients were analyzed based on casual blood pressure readings (resting blood pressure measurement in the health-care provider’s office) and ambulatory blood pressure readings (noninvasive method of obtaining blood pressure readings over twenty-four hours, while the patient is in their own environment, representing a true reflection of their blood pressure)
73% of those taking allopurinol achieved uric acid levels of below 5.0 mg/dL by the end of the study compared to 7% of those taking placebo.
Following analysis, a significant decrease in casual blood pressure was observed in patients treated with allopurinol compared to patients in the control group. An average decrease in systolic blood pressure (pressure when the heart is contracting) of 6.9 mmHg was observed in patients treated with allopurinol, compared to an average decrease of 2.0 mmHg in the control group. An average decrease in diastolic blood pressure (pressure when the heart is relaxed) of 5.1 mmHg was observed in the allopurinol group compared to 2.4 mmHg in the control group.
Similarly, differences in 24-hour ambulatory blood pressure were observed in allopurinol patients compared to control patients. An average decrease in systolic blood pressure of 6.3 mmHg was observed in allopurinol patients compared to an average increase of 0.8 mmHg in the control group. An average decrease in diastolic blood pressure of 4.6 mmHg was observed in allopurinol patients compared to a decrease of 0.3 mmHg in the control group.
67% of patients achieved normal blood pressure by casual and ambulatory criteria during the allopurinol phase, compared to 3% in the placebo phase.
The bottom line
This study concluded that allopurinol may reduce blood pressure in hyperuricemic adolescents with newly diagnosed hypertension.
The fine print
This conclusion still requires confirmation in larger clinical trials with a wider age range. Furthermore, allopurinol has potential side effects and should not be taken without consulting with your physician.
Published By :
Journal of the American Medical Association (JAMA)
Date :
Aug 27, 2008
