Candida albicans test for the screening of phototoxicity in anthistamines

Kim, Tae Heung

Abstract

BACKGROUND: Antihistamine drugs are used widely in many conditions. Although some antihistamines may cause a photosensitive reaction,many physicians are not awae of it.
OBJECTIVE
For examination of the phototoxic potential of antihistamines, we performed the Candida albiecrns test which is simple, cheap, and good for the screening of many drugs. MEHTODS: Thirty microliters of each solute of various antihistamines were applied to the Sabraud dextrose agar plate in which Candida albicans were applied diffusly. Four hours after the application, 60J/cm fo 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 lear zones arround the drug, which means a positive results for the phototoxic potential of the drugs.
RESULTS
Mequitazine, thiethylperazine, perphenazine and cllorromazine 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 tht chlorpromazine, thiethylperazine aderphenazine showed positive results at 0.1%, but negative at 0.01 and 0.001%. Mequitazine was niegative 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 slowed negative results at this study and revealed very weak posit,ive result in 10% diphenhydramine.
CONCLUSION
A photosensitive reaction such as photoallergy and persistent light react,ion may be triggered by the phenothiazine antihistamines. Negative result in 1%, and very weak positive results in 10% diphenhydramine may be due to different mechanism of phototoxicity, or the low phototoxic potential of diphenhydrainine.