RESUMEN
Metformin is an oral antihypoglycemic drug. Its cutaneous side effects are rare and photosensitivity had not been reported. We report 3 cases [a man and two women] of photosensitivity induced by metformin, notified to the Tunisian National Centre of Pharmacovigilance. Onset of the reaction was respectively 22 days, 4 months and 4 years. Daily dose of metformin varied from 1 to 2 tablets. Cutaneous lesions were located in sum exposed sites in all cases with extension to the back in one case. Lesions were eczematous in two cases and erythematous in one case. Lesions healed after stopping metformin in all cases with positive rechallenge in the 1st case. In patient treated by metformin, occurrence of photosensitivity can be related to this drug