Phototoxic potential of thiazide diuretics in normal subjects

Monochromator phototesting has been carried out in 22 subjects before and 2 weeks after therapy with either bendroflumethiazide (bendrofluazide) or hydrochlorothiazide. An increase in erythemal sensitivity was observed in several subjects in those wave bands that are maximally absorbed by the respective drugs in vitro. Both drugs showed similar phototoxic capabilities, yet in clinical practice, reports of photosensitivity caused by hydrochlorothiazide are much more common than those caused by bendroflumethiazide. One possible reason is suggested.