Abstract
It is well known that oral contraceptives (OCs) are still not available in Japan while there are considerable voices for the introduction. On the other hands, there are apprehension about safety of OCs. This report outlines the safety issue of OCs, especially that of newer products belonging to the 2nd and 3rd generations concerning cardiovascular and cerebrovascular accidents and risk of some cancers.
The members of the Pharmacoepidemiology Committee of RAD-AR Council, Japan reviewed original articles regarding this issue, shared information which was given by the articles, and provided this report. The articles were selected from recent reports of pharmacoepidemiology studies published after January of 1996 in major medical journals ; the Lancet, the British Medical Journal, the New England Journal of Medicine, and the Journal of American Medical Association, as well as some former references cited by these articles. These studies have assessed various risks among OC users in comparison with non users or by comparing different types of OCs, and investigated relationship between adverse events and various aspects of oral contraceptive use, such as doses, duration, and timing of use, and various risk factors which users may have.
Although most authors explained their findings cautiously within limitations of observational studies, the results gave considerable impact on the public and regulatory authorities. This kind of pharmacoepidemiology studies based on real world are considered to be indispensable to realize appropriate use of drugs.
