Background:
@EN Antihistamine drugs are used widely in many conditions. Although some antihistamines may cause a photosensitive reaction many physicians are not aware of it.
@ES Objective:
@EN For examination of the phototoxic potential of antihistamines, we performed the Candida albicans test which is simple, cheap, and good for the screening of many drugs.
@ES Methods:
@EN Thirty microliters of each solute of various antihistamines were applied to the Sabraud dextrose agar plate in which Candida albicans were applied diffusely. Four hours after the application, 60J/cm* of UVA was irradiated for two days. The
irradiated plates and nonirradiated control ones were incubated in a dark room for 48 hours, and examined for clear zones arround the drug, which means a positive results for the phototoxic potential of the drugs.
@ES Results:
@EN Mequitazine, thiethylperazine, perphenazine and chlorpromazine showed positive results, whereas others did not. An additional Candida albicans test using 0.1%, 0.01%, and 0.001% of the positive drugs revealed that chlorpromazine,
thiethylperazine
and perphenazine showed positive results at 0.1%, but negative at 0.01 and 0.001%. Mequitazine was negative at 0.1, 0.01, and 0.001%, Additional studies of the Candida albicans test using 5% and 10% of the diphenhydramine and dimenhydrinate,
those
were
known photosensitizers but they showed negative results at this study and revealed very weak positive result in 10% diphenhydramine.
@ES Conclusion:
@EN A photosensitive reaction such as photoallergy and persistent light reaction may be triggered by the phenothiazine antihistamines. Negative results in 1%, and very weak positive results in 10% diphenhydramine may be due to different
mechanisms
of
phototoxicity, or the low phototoxic potential of diphenhydramine (Kor J Dermatol 1993 ; 31(2): 191-196)
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