Siu Y-P et al. (2006) Use of allopurinol in slowing the progression of renal disease through its ability to lower serum uric acid level. Am J Kidney Dis 47: 51–59

Patients with renal disease have reduced uric acid excretion, a problem that can cause kidney function to deteriorate even further. Results of a prospective, randomized, controlled trial indicate that allopurinol lowers serum uric acid levels and reduces the rate of renal degeneration in patients with mild to moderate chronic kidney disease.

Subjects received 100–300 mg/day of allopurinol plus standard therapy (n = 26), or standard therapy alone (n = 26). Standard therapy included antihypertensives and lipid-lowering drugs. Adverse events occurred in only one patient from the allopurinol group, who developed an urticarial skin rash and was prematurely withdrawn from the study.

After 12 months, allopurinol significantly reduced mean serum uric acid levels compared with baseline, by 0.23 mmol/l (3.87 mg/dl; P <0.001). There was a trend towards reduced serum creatinine concentrations in allopurinol-treated patients compared with controls. Worsening renal function (defined as a >40% increase in serum creatinine level) or dialysis dependence occurred in 46% of control patients, but in only 16% of those treated with allopurinol (P = 0.015). Allopurinol had no significant effect on systolic blood pressure or proteinuria.

By decreasing serum uric acid levels, allopurinol might reduce hypertension, glomerular hydrostatic pressure or oxidative stress, which would in turn alleviate renal impairment. Allopurinol therapy might therefore be beneficial for patients with renal disease, subject to confirmation in larger trials with longer follow-up and subgroup analyses.