An Assessment of the Publicly Disseminated Evidence of Safety Used in Decisions to Withdraw Medicines from the UK and US Market

Background

In this study we assessed the evidence made available to the public in support of decisions to withdraw medicines from use for safety reasons.

Methods

Medicines withdrawn from the UK and US markets for safety reasons during the period 1999-2001 were identified from websites of the relevant regulatory agencies in the UK and USA. Supporting evidence was identified from communications made to the public and healthcare professionals at the time of each product withdrawal. The evidence for each product withdrawal decision was classified according to study design i.e. whether it was derived from a clinical trial (the strongest type of evidence), from an observational study, from case reports of adverse drug reactions (the weakest type of evidence) or from other sources.

Results

Eleven products were withdrawn during the period studied. Evidence from clinical trials and comparative observational studies were each cited for two products (18%). Evidence from case reports supported withdrawal of eight products (73%), and in four instances products (36%) were apparently withdrawn on the basis of case reports alone.

Conclusion

Withdrawal of a medicine has important implications for users and, ideally, should be supported by strong evidence. However, we have found that evidence other than case reports (the weakest type of evidence) was rarely cited by the UK and US authorities in support of the withdrawal of medicines.