Aims: To test the association between reporting rates for sparfloxacin-induced phototoxicity and sunlight u.v. exposure, and the effects of regulatory action.
Methods: The reporting rates for phototoxicity with sparfloxacin to the French Pharmacovigilance System or to the Drug Manufacturer were compared with concurrent national mean u.v. exposure obtained from Météo-France, before and after the regulatory restrictions and warnings.
Results: There were 371 severe phototoxic reaction reports during the first 9 months of marketing (reporting rate of 0.4 per thousand treated patients), approximately four to 25 times that reported for other fluoroquinolones. The reporting rate correlated highly (r = 0.873, P < 0.001) with the mean monthly u.v. exposure from sunlight (from Météo-France). Regulatory action including warnings for physicians, and restricted indications dramatically decreased the number of reports, but not the reporting rate.
Conclusions: This is the first demonstration of a strong association between sunlight exposure in a population and drug-induced phototoxicity. Regulatory action had no effect on the reporting rate (individual exposed patient risk), though it solved the public health issue.