The European Commission says that an inverted triangle will shortly appear on the inside leaflet of certain drugs "to easily identify medicinal products that are undergoing additional monitoring".

The black upside-down triangle and accompanying text will encourage patients and doctors to report unexpected adverse reactions through national reporting systems. From September 2013, the symbol will be applied to all drugs authorised after January 1, 2011 that contain a new active substance, plus biological medicines, such as vaccines or plasma-derived products.

The new symbol will also be used on products "for which certain additional information is required post-authorisation", or for which approval is subject to "conditions or restrictions on their safe and effective use". Tonio Borg, European Commissioner for Health and Consumer Policy, said the symbol is easy to recognise and will help authorities obtain more and better information…on possible side effects of a medicine which then can be thoroughly analysed".

He added that "stronger involvement of patients in the reporting on side effects is an integral part of Europe's pharmacovigilance system and – once in place - the new symbol will contribute to strengthen what is already one of the most advanced systems in the world".

Following input from different stakeholders, the European Medicines Agency identified two main options for the symbol – an inverted black triangle and a magnifying glass. The agency plumped for the former after taking into account the views of patients and healthcare professionals, as it is "not linked to any inherent meaning or connotation, is less likely to cause confusion, an incorrect interpretation or alarm to patients".

The EMA also claimed that the inverted triangle "does not clash with other symbols already established for medicinal products", adding that "solid representation is easy to reproduce in a consistent manner".