Allopurinol belongs to a class of molecules known as xanthine oxidase inhibitors, which are molecules that reduce the production of uric acid. Uric acid is made as a result of purine degradation and is normally dissolved in the blood, passed through the kidneys, and excreted in urine. If too much uric acid is produced or it is not properly removed from the body, high levels of uric acid in the blood can lead to medical conditions such as gout (inflammatory arthritis caused by uric acid crystal accumulation between the joints), kidney stones, and kidney disease. Allopurinol can be prescribed for all of these conditions; however, it is primarily used as a preventative treatment for gout.
Allopurinol was reportedly first synthesized by Roland Robins in 1956. The FDA approved its use in 1966 under the brand name Zyloprim (Prometheus Labs). Allopurinol is manufactured through large-scale synthetic organic chemistry methods starting from simple, commercially available precursors.