Cutting edge research into drug side effects could save NHS money and make more drugs safely available
Severe side effects account for one in sixteen NHS hospital admissions and take up four per cent of hospital bed capacity. Many of these are preventable. Research to better understand drug side effects is now finding solutions that will prevent side effects derailing the development of new drugs, and avoid severe side effects from currently-available drugs.
Today, the MRC Centre for Drug Safety Science at the University of Liverpool is launching a public guide, Making Sense of Drug Safety Science, in collaboration with the charity Sense About Science. The guide explains why there is no such thing as a 'side effect free drug', and sets out how understanding more about side effects can help us tailor drugs to patients.
Drugs are currently withdrawn from use if there are reports of severe side effects5. This has already included painkillers, anti-diabetic and anti-HIV drugs. Although severe side effects are usually rare, if a drug is withdrawn because one person in 10,000 suffers, that means 9,999 people have to stop using a medicine that works. By first identifying which rare drug side effects can be predicted, researchers can develop tests that will tell doctors which patients can safely be given a drug.
Scientists at the MRC Centre for Drug Safety Science are developing predictive tests to identify those people who will suffer extreme drug side effects. These will also allow the drugs to be given safely to other patients.
- Some tests developed in this way are already being used: The anti-HIV drug, abacavir, stopped being prescribed because it was linked to a small number of severe skin reactions. It was discovered that only patients with a specific genetic variant were susceptible, allowing drug safety researchers to develop a predictive genetic test. Now the severe rashes have been dramatically cut and abacavir continues to be used as an effective drug for the majority of patients.
- Other tests are currently being developed based on recent scientific discoveries: Carbamazepine is a drug used to treat epilepsy and bipolar but a rare side effect of this medicine is a life-threatening skin condition, called Stevens Johnson Syndrome (SJS)6. Patients who developed SJS when taking this drug were identified to carry a specific genetic variant. Scientists are now evaluating whether this genetic variant can be used to predict whether patients are likely to develop SJS following carbamazepine therapy7.
- Predictive tests are also used during drug development. Recent scientific advances from the study of drug-induced liver injury have led to the development of new experimental tools. These tools are being used to develop tests that can identify whether new candidate drugs have the potential to cause injury before they are tested in humans8.
Comments
Patricia Roberts who suffered from a disease caused by severe drug side effect: "When the symptoms started, I had no idea about Stevens-Johnson Syndrome and that it was caused by the drug I was taking. Although it is rare, it can be fatal in just a few hours so you need immediate treatment. I feel passionately that more people need to know about the enormity of this condition so they can get the right treatment quickly enough; but, most importantly, we need prevention."
***Patient case study is available in full from Sense About Science***
Professor Kevin Park, director of the MRC Centre for Drug Safety Science "Our research is increasing what we know about drug safety and helping us to give people better information about the risks associated with medicines. Improving our understanding of the mechanisms that lead to serious adverse side effects will lead to existing medicines being prescribed more safely and new medicines being developed more effectively. Through this guide we want to share with patients, GPs and other health professionals why drug safety science matters to everyone."
Emily Jesper, co-editor of the guide, Sense About Science: "Experiencing side effects is unpleasant, and not understanding them is frustrating. While it's impossible to have a drug with no side effects, we want to demystify why they happen and what can be done about them."
Martyn Lobley, GP and medical journalist: "Show me a drug with no side effects and I'll show you a drug with no benefits. When you take a medicine you're entering into a bargain. The prescriber, to the best of their knowledge, gives you a medicine that will do you more good than harm, but you have to accept the risk that it may do you more harm than good. For some medicines, we understand the risks and can mitigate them, but for others the knowledge is just not there yet."
More information:
Pirmohamed M et al Adverse drug reactions as cause of admission to hospital: prospective analysis of 18,820 patients. BMJ 2004: 329:15-19 www.bmj.com/content/329/7456/15
Provided by SAGE Publications
