A CASE OF SULFONYLUREA INDUCED PHOTOTOXICITY IN AN ELDERLY SUBJECT - A RARE CASE REPORT

Sulfonylureas are insulin secretagogues used in the management of type 2 diabetes mellitus. The most common side effects are hypoglycemia and weight gain. Less frequent side effects are nausea, vomiting, cholestatic jaundice, agranulocytosis, generalized hypersensitivity reactions which include dermatological reactions. Dermatological reactions of sulfonylurea include photosensitivity. Drug induced photosensitivity is one of the important adverse drug reaction. Hence we would like to present here a case of sulfonylurea induced photosensitivity in an elderly diabetic male. He presented with rashes, itching, and intolerance to light and eruptions with exfoliation of skin over the sun exposed parts of the body. INTRODUCTION: Sulfonylureas are insulin secretagogues used in type 2 diabetes mellitus. They are substituted aryl sulfonylureas. They differ by substitutions at the para position on the benzene ring and at one nitrogen residue of the urea moiety. The sulfonylureas are divided into two generations. The first generation sulfonylureas (tolbutamide, tolazamide and chlorpropamide) are rarely used now. The second generation sulfonylureas are more potent and include glimepiride, glipizide and glyburide. Main side effects of sulfonylureas are hypoglycemia and weight gain. Other less common side effects are nausea, vomiting, cholestatic jaundice, agranulocytosis, generalized hypersensitivity reactions which include dermatological reactions like photosensitivity1. Photosensitivity is one of the neglected side effects of sulfonylureas and here we present a rare case of sulfonylurea induced photosensitivity. CASE REPORT: A 60 year old male patient presented with rashes, itching, and intolerance to light with exfoliation of skin over the sun exposed parts of the body. He had developed phobia for exposure to light and avoided taking pictures with camera flash. He was known diabetic on treatment with tablet glyburide 5mg (sulfonylurea) and metformin 500mg twice daily since 2 years. The patient was treated with sunscreen lotion for his skin lesions, but showed no improvement even after 2 months. Later, upon review of his drug history, it was revealed that glyburide (sulfonylurea) caused phototoxicity, and was withdrawn. The patient was put on an alternate hypoglycemic drug combination of pioglitazone 15mg and metformin 500mg twice daily. He also continued sunscreen application and sun protection. He improved gradually within 15 days and this suggests that it is a case of sulfonylurea induced phototoxicity.