Effect of the British warning on contraceptive use in the General Medical Service in Ireland

Abstract

In October 1995 the UK Committee of Safety of Medicine (CSM) issued a warning about the safety (thromboembolic disease) of the third generation oral contraceptive steroids (OCS) recommending a switch to older agents except where women were intolerant of first and second generation OCS. Advice by the Irish regulatory authority (Irish Medicines Board) did not recommend such a switch. This pill scare lead to some UK users stopping OCS mid-cycle and a rise subsequently in abortions and pregnancies was noted. To determine whether local or UK advice was followed we obtained data from the General Medical Service (GMS) Scheme on the use of contraceptive steroids prescribed before and after the CSM's warning. The results show a clear shift from usage of the third generation OCS to the second generation OCS and norgestimate-containing OCS. We have also noted a marked fall in the overall use of the combined OCS, a trend that was noted in the U.K. It is clear that prescribers and pill users were influenced more by advice from the UK than by Irish regulatory authority. There is now a centralised European mechanism to licence drugs in the European Union (EU). We need to develop an EU perspective to issues of drug safety, as constituent nations are no longer isolated islands.

PIP: In October 1995, the UK Committee on Safety of Medicines (CSM) issued a warning about the thromboembolic risk of third-generation oral contraceptives (OCs) and recommended a switch to second-generation formulations. The Irish Medical Board did not issue such a recommendation, but instead requested further study to assess the possible impact of bias and confounding. However, a review of OC prescribing data from before and after the CSM warning indicated that prescribers and pill users in Ireland were influenced more by the UK warning than by Irish regulatory agencies. All OCs prescriptions dispensed in Ireland's Eastern Health Board area (representing 40% of the General Medical Service) from January 1995 to November 1996 were examined. Prescriptions for third-generation OCs declined from 53% of total contraceptive steroid use in January 1995 to 30% in November 1996. This decline was paralleled by an increase of 12% (from 31% to 43%) in use of second-generation OCs and a 9% rise (from 9% to 18%) in distribution of norgestimate-containing OCs. These findings attest that decisions made in one country may have major consequences beyond geographic boundaries, even when the decision is contrary to another country's public health policy. Recommended, to ensure a more standardized approach to pharmacologic vigilance, is development of a European perspective on issues of drug safety.