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Demonstration of quinolone phototoxicity in vitro
B Przybilla1, A Georgii, T Bergner
1Dermatology Clinic and Policlinic, Ludwig Maximilian University Munich, FRG.
Abstract:
The 'first-generation' quinolones cinoxacin, nalidixic acid, oxolinic acid, pipemidic acid and rosoxacin and the newly developed quinolones ciprofloxacin, enoxacin, fleroxacin, norfloxacin and ofloxacin were screened in vitro at 10(-5), 10(-4) and 10(-3) M concentrations for ultraviolet (UV)-induced phototoxic effects in a photohemolysis test. At 10(-3) M, photodependent effects of norfloxacin could not be evaluated, as hemolysis occurred without irradiation. All other compounds with the exception of ciprofloxacin were found to be phototoxic at 10(-3) M and some also at 10(-4) M. Hemolysis was UV dose dependent and for all compounds most prominent after exposure to UVA-rich radiation except for fleroxacin which was most active in the UVB range. Besides fleroxacin, also oxolinic acid, pipemidic acid and rosoxacin induced hemolysis with irradiations rich in UVB. It is concluded that quinolones have to be regarded as potentially phototoxic substances. Therefore intense light exposure should be avoided during treatment with these agents.
Insights
Quinolone antibiotics can cause phototoxic reactions, leading to skin damage upon UV exposure. Patients should avoid intense light during treatment with these potentially phototoxic drugs.
Area of Science:
- Pharmacology
- Photobiology
- Dermatology
Background:
- Quinolones are a class of antibiotics used to treat bacterial infections.
- Some quinolone derivatives have been associated with photosensitivity reactions.
- Understanding the phototoxic potential of different quinolones is crucial for patient safety.
Purpose of the Study:
- To evaluate the in vitro phototoxic effects of first-generation and newer quinolone antibiotics.
- To determine the dose-dependency and UV spectrum-specificity of quinolone-induced phototoxicity.
Main Methods:
- In vitro photohemolysis assay was used to screen ten quinolone antibiotics.
- Compounds were tested at concentrations of 10(-5), 10(-4), and 10(-3) M.
- UV irradiation (UVA and UVB) was employed to assess photodependent hemolysis.
Main Results:
- Most tested quinolones exhibited phototoxicity at 10(-3) M, with some showing effects at 10(-4) M.
- Norfloxacin induced hemolysis even without UV irradiation at 10(-3) M.
- Phototoxicity was generally more pronounced with UVA, except for fleroxacin, oxolinic acid, pipemidic acid, and rosoxacin, which were more active under UVB.
Conclusions:
- Quinolones should be considered potentially phototoxic agents.
- Patients prescribed quinolones should be advised to avoid intense light exposure.
- Further research into the phototoxic mechanisms of quinolones is warranted.