Allopurinol is primarily used to treat conditions caused by high levels of uric acid in the body. It is commonly prescribed for gout, a type of arthritis that results from the buildup of uric acid crystals in the joints. By inhibiting the enzyme xanthine oxidase, it reduces the production of uric acid, preventing gout attacks and the formation of uric acid kidney stones. Additionally, it is used in managing hyperuricemia, which can occur as a side effect of chemotherapy or radiation therapy in cancer patients. Allopurinol helps prevent complications like tumor lysis syndrome, where rapid cell breakdown leads to elevated uric acid levels. It is also beneficial in treating certain types of recurrent calcium kidney stones. Patients with Lesch-Nyhan syndrome, a genetic disorder causing excessive uric acid production, may also use allopurinol to manage symptoms. Long-term use can help reduce the frequency and severity of gout attacks and improve overall quality of life for affected individuals.