Studies on the phototoxic effects of oral antidiabetics and diuretics.

A number of sulphonamide derived oral antidiabetics (chlorpropamide, glibenclamide, glipizide, gliquidone, glymidine, tolazamide and tolbutamide) and diuretics (bemetizide, bendroflumethiazide, benzylhydrochlorothaizide, bumetanide, butizide, chlortalidone, furosemide, hydrochlorothiazide, hydroflumethiazide, indapamide, piretanide, polythiazide, trichlormethiazide and xipamide) were investigated for phototoxicity in a cell culture model. Cell death dependent on UVA fluence and test substance concentration was observed in the presence of the oral antidiabetics glibenclamide and gliquidone, as well as the diuretics bemetizide, bendroflumethiazide, benzylhydroxhlorothiazide, bumetanide, butizide, hydrochlorothiazide, hydroflumethiazide, piretanide, polythiazide and trichlormethiazide. Bendroflumethiazide was phototoxic at 5 x 10(-5) mol/l and higher concentrations, bemetizide, benzylhydrochlorothiazide, bumetanide and hydroflumethiazide were phototoxic at 2.5 x 10(-4) mol/l and higher concentrations, and the oral antidiabetics glibenclamide and gliquidone as well as the diuretics butizide, hydrochlorothiazide, piretanide, polythiazide and trichlormethiazide were phototoxic at 5 x 10(-4) mol/l and higher concentrations. The oral antidiabetics chlorpropamide, glipizide, glymidine, tolazamide and tolbutamide as well as the diuretics chlortalidone, furosemide, indapamide and xipamide did not induce phototoxicity in this assay.