A STUDY OF PHOTOSENSITIVITY OCCURRING WITH CHLORPROMAZINE THERAPY

[摘要] Nine of 72 patients under chlorpromazine therapy developed abnormal reactions in test sites to UV rays in the spectral zone below 3100 A. Reactions appeared to be exaggerations of the normal sunburn response. A 1% solution of chlorpromazine hydrochloride, examined spectrophoto-metrically, showed complete absorption of the wave lengths between 2000 and 3700 A. Thus the absorption pattern of the drug included the UV rays shorter than 3100 A. Examinations of the urine of 19 of the patients revealed no abnormal porphyrins. The presence of weakly positive reactions for prophobilinogen in certain specimens is unexplained. None of the subjects showed clinical evidence of hepatic dysfunction or porphyria. Several possible mechanisms of the production of photosensitivity by chlorpromazine were discussed. Dermatitis medicamentosa of a maculopapular, urticarial type occurred in approximately 10% of the subjects. In 2 instances these reactions were apparently precipitated by exposure to natural sunlight.