Adverse effects warnings absent from 40% of drugs

Information on adverse effects of commonly prescribed drugs is often inadequate, a study has shown.

A study of the 50 most commonly prescribed drugs in England showed that 20 (40%) of the information leaflets supplied made no mention of adverse effects.

Only six (12%) used recommended EU terms and a further 20 used a wide range of other verbal descriptions.

Numerical indication of risk was included in only four (8%) of leaflets and more than half (52%) presented long lists of adverse effects in continuous text, the study showed.

Authors wrote: 'Most patients receive no information, whereas some are given verbal descriptors, both of which lead to overestimation of the risk.

'Very few of the patient information leaflets assess used currently described best practice.'

Drug Safety (2008) 31: 305-312