Photosensitizing potential of ofloxacin.

BACKGROUND: The relative phototoxic risk of ofloxacin, one of the newer fluoroquinolones, was compared with that of an active control of known but low phototoxic risk, naproxen.

METHODS: A randomized, controlled, open-label trial was used with a standardized phototoxic assay completed at baseline, midway through, and at the termination of the 12-day trial. The trial was held at a dermatology research laboratory located at a large tertiary referral and teaching hospital. Thirty healthy volunteers who met the inclusion criteria and met none of the exclusion criteria were enrolled. Twenty-seven patients completed the trial. Three subjects failed to complete the trail. One subject developed an exaggerated response to the initial photoexposure and was dropped from the study. The other two subjects failed to return for follow-up visits.

RESULTS: Both ofloxacin and the active control agent, naproxen, significantly increased the subjects' response to the tested solar and ultraviolet irradiation. There was, however, no significant difference between the responses observed for ofloxacin versus naproxen at any time.

CONCLUSIONS: Ofloxacin possesses a definite but low potential to cause phototoxic reactions in humans. These study data, in concert with surveillance data, suggest a hierarchy of phototoxic risk among the fluoroquinolones: fleroxacin > lomefloxacin, pefloxacin > ciprofloxacin > enoxacin, norfloxacin, ofloxacin. The impact that phototoxicity risk will have on selecting the optimum member of a large drug family appears to be substantial in outpatient and ambulatory settings and minimal in inpatient settings.