Photohemolysis Due to Diuretic Drugs

Abstract

The diuretics acetazolamide, bemetizide, bendroflumethiazide, benzthizide, benzylhydrochlorothiazide, bumetanide, butizide, chlorazanile, chlorothiazide, chlortalidone, clopamide, cyclopenthiazide, cyclothiazide, diazoxide, etozoline, furosemide, hydrochlorothiazide, hydroflumethiazide, indapamide, mefruside, metolazone, piretanide, polythiazide, trichlormethiazide, and xipamide were screened in vitro for phototoxic effects by the means of a photo- hemolysis test. Suspensions of red blood cells and test substances were irradiated with ultraviolet B (UVB) (TL 20W/12 light bulbs), ultraviolet A (UVA; UVASUN 5000 apparatus), visible light (prototype, VL lamp), or with solar-simulating radiation (SOL 3 lamp). In all, 19 of the 25 tested compounds exhibited phototoxic hemolysis in this model. Eight known photosensitizers described as inducing clinical photosensitivity in humans were identified in this model. In addition, 11 diuretics not previously described as exerting photosensitizing side effects in humans were identified as phototoxic agents.