Regulators decide to authorise medicines after assessing their benefits and risks based on the results of clinical trials. Only medicines whose benefits have been shown to be greater than their risks can reach the market. This ensures that patients can access the treatments they need without being exposed to unacceptable side effects.
Clinical trials involve a relatively small number of patients for a limited period of time. Patients in clinical trials are carefully selected and followed up very closely under controlled conditions. In a real-life setting, a larger number of patients will use the medicine; they may have other diseases; and they may be taking other medicines. Some less common side effects may only occur once a medicine has been used for a long time by a large number of people. It is therefore vital that the safety of all medicines continues to be monitored while they are in commercial use.
Information is continuously collected after a medicine is placed on the market to monitor real-life experience with the product. European regulatory authorities closely monitor this information to make sure that the benefits of medicines continue to outweigh their risks. The same monitoring methods are used across the EU so that European regulators can share the information gathered in individual EU countries. This provides a wealth of knowledge for regulators to rely upon when making decisions, and enables them to act quickly to ensure patient safety when required, such as providing warnings to patients and healthcare professionals or restricting the way a medicine is used.