How is the safety of medicines regulated? 

All medicines licensed for use in the UK are strictly regulated to ensure they are as safe as possible.

The entire process of medicine development is controlled, and monitoring continues after medicines become widely available.

In the UK, the Medicines and Healthcare Products Regulatory Agency (MHRA) is the organisation that looks after the safety of prescribed medicines and other health devices and equipment.

Its main job is to make sure that medicines and medical devices, from painkillers to pacemakers, work properly and are acceptably safe.

The MHRA works closely with the European regulator, the European Medicines Agency (EMA), which oversees the safety of medicines across Europe. In some cases, the EMA takes the lead in licensing medicines used in the UK.

Ensuring safety

No product is completely risk free, so the MHRA uses as much information as it can to ensure the benefits of medicines for patients justify any possible risks.

Both the MHRA and EMA routinely carry out inspections to check all parts of the medicine development process, from testing to manufacturing, are carried out in line with strict regulations.

The MHRA assesses the results of clinical trials to decide whether or not new medicines should be licensed for use. Clinical trials are research studies that carefully test the safety and effectiveness of medicines, using strict criteria.

No medicine or medical device can be used in the UK until the MHRA or EMA has given it a licence that sets out how it should be used and which health condition it should be used to treat. Read more about licensing medicines.

However, no medicine is completely risk free and medicines can affect different people in different ways. For example, depending on your age, sex and what other medicines you are taking, a medicine might cause you to have a side effect that someone else who is also taking it wouldn't have.

Ultimately, you and your healthcare professional have to weigh up the pros and cons of each medicine when deciding on the most appropriate treatment.

Monitoring safety

The MHRA continues to monitor the safety of medicines once they are in wider use by checking reports about any problems or defects, and reviewing new scientific evidence on different medicines.

If any problems arise, the MHRA can take action to deal with it. This may mean alerting healthcare professionals about a potential issue with a medicine, and withdrawing a medicine from the market if it becomes apparent that side effects outweigh the benefits.

Reporting an adverse effect

The Yellow Card Scheme is a special reporting system for possible adverse effects of medicines.

If the healthcare professional treating you thinks a medicine may have caused a potentially concerning effect, they will fill in a report and send it to the MHRA.

You can also use the Yellow Card Scheme yourself, or on behalf of a child or adult in your care, by:

  • calling 0808 100 3352 to report an adverse effect over the phone
  • asking your pharmacist for a Yellow Card form you can send in the post
  • logging on to the Yellow Card Scheme website to report an adverse effect online

Side effects: the Yellow Card Scheme

All medicines can cause side effects. Some may not yet be known, so that's why it's important for people to report to the Yellow Card Scheme.

Media last reviewed: 22/06/2015

Next review due: 22/06/2017


Learn about the watchdogs that monitor the NHS and other public healthcare providers

Page last reviewed: 31/10/2014

Next review due: 31/10/2017