Allopurinol is use to prevent re-perfusion injury.

• Allopurinol inhibits xanthine oxidase which is responsible for generating reactive oxygen species (ROS) during ischemia-reperfusion.
• When blood flow is restored to ischemic tissues, a sudden surge of ROS can cause oxidative damage, inflammation, and cell death.
• By reducing ROS production, allopurinol helps protect tissues from oxidative stress, preserving cellular function and reducing injury in conditions like myocardial infarction and organ transplantation.