The Pharmaceutical Journal
Vol 270 No 7234 p143
1 February 2003

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Pill risk warnings poorly understood

Few educated women fully understand the risk of thrombosis associated with the contraceptive pill as it is explained in current patient information leaflets.

Warnings on thrombosis risk to be included in packs of third generation oral contraceptives were set out by the Committee on Safety of Medicines in 1999.

Theo Raynor, professor of pharmacy practice, medicines and their users, Leeds university, and colleagues assessed how well 186 female university students, including many current or past pill users, understood the information. Some women were provided with an explicit statement on relative risk in an attempt to clarify the issue (see panel). They found that less than 12 per cent of women fully understood the absolute levels of risk of thrombosis from taking the pill and from being pregnant.

When asked to assess risk in the same terms as used in the leaflet, one third still gave incorrect estimates. A fifth of women showed no understanding of the relative risk of a thrombosis while taking the pill compared with that while pregnant. Less than 40 per cent fully understood the relative risks involved. The additional statement on relative risk appeared to have no effect on understanding.

The authors of the study (Contraception 2002;66:305) say that, while the CSM requires exhaustive testing of drugs themselves, it requires little or no testing of accompanying information. They strongly urge the CSM to revise the wording of the information for the contraceptive pill, which is currently provided to millions of women in the United Kingdom. Speaking to The Journal, Professor Raynor said: "Although it is clear that the current wording does not work, we do not yet know what would. It is apparent that it is difficult to get these messages of risk across — even to people who might be expected to understand."

His project, on the understanding of the risks of side effects of medicines in general, is now focusing on alternative ways to present this information. In a joint programme with the psychology department at the University of Reading, headed by Professor Dianne Berry, researchers will be looking at the effect of verbal descriptors of risk used together with percentages. Other suggestions had been to use graphical representations of risk, although Professor Raynor did not think this would be suitable for medicines listing multiple side effects.

A spokeswoman for the Department of Health said that the Medicines Control Agency was aware of difficulties in interpreting advice and said that the issue was under review. She added that the MCA would be making an announcement regarding this problem later this year.