MHRA Signal Summaries

What is a safety signal?

A safety signal is information on a new or known adverse event that may be caused by a medicine and requires further investigation. Signals can be detected from any available data source, including adverse drug reaction (ADR) reports received via the Yellow Card scheme, published scientific literature, clinical trials and observational studies. Reports from spontaneous reporting schemes, such as the Yellow Card scheme are the most common source of safety signals. During the MHRA’s signal detection activities, reports of suspected ADRs are evaluated along with the additional sources of information to determine if the safety profile of a medicinal product has changed.

When reviewing the signal summaries, it is important to remember that:  

The appearance of a signal in these summaries does not necessarily mean that the MHRA have concluded that the reaction is causally associated with the suspect drug. Many factors need to be taken into account when assessing potential safety signals. The MHRA will update each summary including when a final recommendation is reached.  

For these reasons, it is important you do not stop taking your medicine without consulting your healthcare professional first. If you are concerned about a potential side effect you may have experienced and need medical advice, please contact your healthcare professional who will be best placed to advise you.  

If you are worried about your health: 

Talk to your doctor, pharmacist or nurse 

Call the NHS 

NHS 111 in England and Scotland on 111 (textphone 18001 111) 

NHS Direct Wales/Galw IECHYD Cymru on 0845 46 47 (textphone 0845 606 46 47) 

NHS Northern Ireland 

Recommendations for safety signals

The MHRA will assess each safety signal individually and issue subsequent recommendations. The recommendations issued by the MHRA may be one or a combination of the recommendations below:

Further evaluation or action at present is not recommended

Currently the available evidence at this time does not indicate a causal association between the drug and the reaction. The signal will be kept under review during routine signal detection activities and should further evidence be received it will be revisited.

Additional information from the marketing authorisation holder (MAH) is recommended

This information may include a cumulative review of all the information held by the MAH and the information available in the published medical literature. These reviews can be asked for on request or asked for as part of the next routine periodic safety update report.

UK expert advice is recommended

The MHRA may seek independent expert advice on a drug safety signal from the Commission on Human Medicines (CHM) and the CHMs Expert Advisory Groups (EAG).

Raising the signal within the European network is recommended

When a medicine is licensed through the European licensing procedure (e.g. via the centralised procedure) the MHRA will refer these signals for review via the European network. These signals summaries will then link to the review via the Pharmacovigilance Risk Assessment Committee (PRAC).

Regulatory action is recommended, such as:

• updating of the product information (summary of product characteristics (SPC) and patient information leaflet (PIL))
• Urgent safety restrictions

A glossary of key words is available to help with the interpretation of the signal summaries.