[Pill matters: targeted research into side effects necessary].

The paper by Van Hunsel et al. in this issue of the Nederlands Tijdschrift voor Geneeskunde (Dutch Journal of Medicine) describes reports of side effects among users of hormonal preparations containing cyproterone acetate (Diane-35 and generics) following reports from France of fatal venous thrombosis and subsequent regulatory action. These preparations are licensed for treatment of acne and hirsutism, but are used as oral contraceptives. Following extensive media attention, Lareb (The Netherlands Pharmacovogilance Centre) has received hundreds of reports, more than half of which were received from patients and not physicians, and in many cases referred to side effects that had occurred years ago. It is noteworthy that oral contraceptives containing cyproterone acetate have been known to be unsafe since 2001, and still they have been used by more than 100,000 women in the Netherlands. The information from Lareb also shows that a pharmacovigilance system based on voluntary reports by physicians and patients is not sufficient to detect increased frequencies of 'common' side effects.