Photosensitivity Studies With Demethylchlortetracycline and Doxycycline

Abstract

Of 30 volunteers, ten were given demethylchlortetracycline (600 mg/day), ten, doxycycline (200 mg/day), and ten, a placebo, for one week, and then all were taken on a voyage designed to maximize sun exposure. Nine out of ten receiving demethylchlortetracycline developed photosensitive eruptions, two of ten receiving doxycycline were also positive; while one volunteer on placebo was doubtful. These results support the concept of demethylchlortetracycline as a powerful phototoxic agent and suggest that doxycycline in the doses used will cause a lower incidence of this annoying side effect.