Allopurinol and endothelial function: A systematic review with meta-analysis of randomized controlled trials.

Oxidative stress and endothelial dysfunction are two inter-related conditions commonly seen in patients with cardiovascular risk factors. The enzyme, xanthine oxidase, is an important contributor to these phenomena but to a variable degree in different patient populations. This meta-analysis will summarize the effect of allopurinol, an established xanthine oxidase inhibitor, on endothelial function among patients with different comorbidities.