Phototoxicity in quinolones: comparison of ciprofloxacin and grepafloxacin

Skin photosensitizing reactions have been reported during treatment with fluoroquinolone antibiotics. The incidence and severity of such reactions, however, appear to differ between agents. The photosensitizing effect of grepafloxacin 400 and 600 mg once daily was compared with that of ciprofloxacin 500 mg bd and placebo in a double-blind trial involving 32 healthy subjects. Skin photosensitivity, expressed as the minimal erythemal dose (MED), was measured before treatment and towards the end of the 7 day treatment period. Grepafloxacin showed a mild photosensitizing effect comparable to that of ciprofloxacin, with significant reductions in MED at 335 +/- 30 and 365 +/- 30 nm. However, few subjects showed MEDs outside the normal range, and MEDs consistently returned to baseline values within 1 week of stopping treatment. No significant differences between the effects of grepafloxacin and ciprofloxacin could be observed. It is concluded that grepafloxacin has a weak, UVA-dependent and rapidly reversible photosensitizing effect.