Objectives: To determine the effects of allopurinol in the treatment of chronic prostatitis

Search strategy: Trials were searched in computerized general and specialized databases (MEDLINE, Cochrane Library, Cochrane Prostate Group database), bibliographies of obtained articles, and direct contact with authors.

Selection criteria: All randomized trials of allopurinol versus placebo used to treat patients with chronic prostatitis. Acute prostatitis, bacterial prostatitis, and asymptomatic prostatitis were excluded. The main outcome measure was the change in patient-reported discomfort.

Data collection and analysis: The reviewers extracted the data independently for the outcomes of change in patient-reported discomfort, investigator graded prostate pain, leukocyte counts, and biochemical indices.

Main results: Only one trial with 54 men lasting 240 days (with 330 days of follow-up) met study inclusion criteria. There was a statistically significant change favoring allopurinol in patient-reported discomfort between the study and control groups at follow-up. Between days 45-225, the mean score was -0.95 (s.d. 0.19) for the allopurinol group (7 men), compared with -0.47 (s.d. 0.21) for the placebo group (7 men). The weighted mean difference (WMD) was -0.48 (95%CI -0.690, -0.270). The mean score between days 45-135 was -1.08 (s.d. 1.29) for the 25 men in the allopurinol group, compared with -0.21 (sd 0.97) for the 14 men in the control group. The WMD was -0.87 (95%CI -1.587, -0.153). The allopurinol group had significantly less investigator graded prostate pain and had lower levels of serum urate, urine urate, and expressed prostatic secretion urate and xanthine. No significant differences between the two groups regarding leukocyte counts were found. No patient receiving allopurinol had any significant side effects. Three patients in the placebo group dropped out because of side effects.

Reviewer's conclusions: One small trial of allopurinol for treating chronic prostatitis showed improvements in patient-reported symptom improvement, investigator-graded prostate pain, and biochemical parameters. However, the data provided, the measures used, and the statistics presented do not make these findings convincing that changes in urine and prostatic secretion composition regarding purine and pyrimidine bases resulted in the relief of symptoms. Further studies of allopurinol treatment using standardized and validated outcomes measures and analyses are necessary to determine whether allopurinol is effective.