Abstract

Clinical trials carried out before licensing new drugs are designed primarily to assess efficacy, but will give some indication of the adverse effects of the drug, particularly those that are dose-related. However, serious adverse effects are unlikely to be detected at this stage. Postmarketing surveillance is needed to identify such adverse effects, and any specific groups of patients who are at particular risk. The Committee on Safety of Medicines (CSM) increasingly requests manufacturers to undertake postmarketing surveillance on new products intended for wide and long-term use, but it cannot require this as a condition of licensing.