The link between sunshine and phototoxicity of sparfloxacin

Aims To test the association between reporting rates for sparfloxacin-induc ed phototoxicity and sunlight u.v. exposure, and the effects of regulatory action. Methods The reporting rates for phototoxicity with sparfloxacin to the Fren ch Pharmacovigilance System or to the Drug Manufacturer were compared with concurrent national mean u.v. exposure obtained from Meteo-France, before a nd 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 m onthly u.v. exposure from sunlight (from Meteo-France). Regulatory action i ncluding warnings for physicians, and restricted indications dramatically d ecreased 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. Regulato ry action had no effect on the reporting rate (individual exposed patient r isk), though it solved the public health issue.