Impact of irbesartan, an angiotensin receptor blocker, on uric acid level and oxidative stress in high-risk hypertension patients.

Hyperuricemia is a known cardiovascular risk factor. The angiotensin II receptor blocker (ARB) losartan is known to decrease serum uric acid (UA) level. A recent in vitro study demonstrated a strong interaction between irbesartan and UA transporters that exceeded that of losartan. The purpose of the present study was to evaluate the hypouricemic effect of irbesartan in a clinical setting. A total of 40 high-risk hypertensive outpatients with coronary artery disease, cerebrovascular disease and/or diabetes complications who were taking ARBs other than irbesartan and losartan were enrolled in this study. After a 4-week control period, the patients' prescribed ARBs were exchanged for an equivalent dose of irbesartan. We assessed blood pressure, heart rate, serum UA level, parameters of lipid and glucose metabolism, cardiac and renal function and inflammatory and oxidative stress markers in blood samples taken immediately before the initiation of irbesartan treatment and again after 12 weeks of treatment. All 40 recruited patients were followed (31 men and 9 women, mean age: 68 years) without any dropouts. During the 12 weeks of irbesartan treatment, no significant changes in blood pressure, heart rate, parameters of lipid or glucose metabolism or other biomarkers of cardiac function, renal function, or inflammation were observed. However, UA level (5.9±1.6 to 5.5±1.6 mg ml(-1), P=0.028) and the oxidative stress marker derivative reactive oxygen metabolites (dROMs) (354±83 to 310±65 U.CARR, P<0.001) were significantly lower at 12 weeks of treatment compared with before treatment. These results suggest that irbesartan has beneficial effects on hyperuricemia and oxidative stress.