Photoreaction potential of orally administered levofloxacin in healthy subjects

OBJECTIVE: TO evaluate the photoreaction potential of levofloxacin on expos ure to solar-simulating radiation. Solar-simulating is ultraviolet (UV) lig ht, defined as UVA in the 320-400 nm range and UVB in the 290-320 nm range. DESIGN: In a single-center, double-blind, randomized study, 30 adults (20 m en, 10 women) received oral levofloxacin (500 mg qd x 5 d) or placebo. At b aseline photoexposure prior to drug administration, each subject was expose d to UVB light at 0.75, 1.0, and 2.0 times the minimal erythema dose and to UVA light (25 J/cm(2)). Photoexposure was repeated on day 5, two hours fol lowing final drug administration, and response was determined using both a photoreaction rating scale and investigator assessment. RESULTS: Using the photoreaction rating scale, following UVB exposure on da y 5, no abnormal photoreactions were observed among levofloxacin recipients . UVA exposure was associated with mild reactions in 20 of 24 levofloxacin- treated and three of six placebo-treated subjects, with no associated sympt oms. By investigator assessment, all subjects had a negative reaction to UV B photoexposure, and 10 of 24 levofloxacin-treated and three of six placebo -treated subjects had a photoreaction following UVA photoexposure. Dermal r eactions were mild and similar for both treatment groups. No subject experi enced an immediate wheal-and-flare reaction. There were no statistically si gnificant differences between treatment groups for any of the comparisons. CONCLUSIONS: Levofloxacin has a low photosensitizing potential when adminis tered to healthy subjects.