The Experimental Production of Drug Phototoxicity in Guinea Pigs

Abstract

Phototoxicity to chlorpromazine has been demonstrated in guinea pigs. This phototoxic reaction, characterized by erythema and necrosis of the ears, is produced regularly and easily. The source of ultraviolet was either a bank of fluorescent ultraviolet lamps or a high-pressure mercury vapor lamp. Phototoxicity was demonstrable only when a tough transparent plastic (Mylar) was interposed between the light source and the experimental animals. Without the plastic, the phototoxic response was masked by the normal erythema. It was not possible to consistently demonstrate phototoxicity to demethylchlortetracycline or chlorothiazide using these methods.