Allopurinol as add-on treatment for mania symptoms in bipolar disorder: systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Since bipolar disorder seems to be associated with purinergic system dysfunction, allopurinol might be effective in treating symptoms of mania. AIMS: To estimate the efficacy and tolerability of allopurinol as adjunctive treatment for mania symptoms in people with bipolar affective disorder.
METHOD: We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) comparing the effects of adjunctive allopurinol and placebo on mania symptom changes.
RESULTS: Five RCTs were included in the meta-analysis. Participants with allopurinol augmentation had a significantly greater decrease in mania symptoms than those with placebo (SMD = -0.34, P = 0.007), especially in people with the most severe forms of mania. Remission rates, although based on only two studies (n = 177), were significantly higher among individuals receiving allopurinol, whereas for discontinuation and side-effects no difference was found.
CONCLUSIONS: Our finding of a small to moderate effect size and overall low evidence for add-on allopurinol in reducing mania symptoms indicate that its use in routine practice needs further elucidation. © The Royal College of Psychiatrists 2017.