Allopurinol promotes and butylated hydroxy toluene prevents sugar-induced cataractogenesis.

Rats fed a high galactose (30% galactose) diet (w/w) or made diabetic by injecting streptozotocin developed mature cataracts in approximately 45 and 90 days, respectively. Addition of allopurinol, a commonly used drug in the therapy of gout, to the high galactose diet or to the normal diet fed to diabetic rats advanced cataractogenesis in both the groups by approximately 50%. Allopurinol fed to control rats did not cause cataract formation. Feeding butylated hydroxy toluene (BHT), an antioxidant, prevented the allopurinol-induced advancement of cataract formation in galactosemic and diabetic rats. Assuming that these results are applicable in human subjects, there is need for caution in using allopurinol for the therapy of gout in diabetic subjects.