A new study from Queen Mary University of London found that 9% of all adverse drug reactions (ADRs) reported to the UK medicines regulator are associated with medications where side effect risk is partly dependent on patient’s genes. Of this subset of ADRs, 75% were associated with only three genes that impact how the body processes medication. Genetic testing before prescribing could therefore help avoid ADRs in these cases.
Over the past 60 years, the MHRA’s Yellow Card scheme recorded over one million reports of side effects – also known as adverse drug reactions (ADRs) – to medications. Previous studies have indicated that more than 99% of individuals have genetic variants which could lead to an adverse response to certain drugs. In some cases, these reactions can be serious and lead to further health problems, longer hospital stays, or even death. The cost of ADRs to the NHS is estimated to be more than £2 billion a year.
A new study, published in PLOS Medicine, led by Dr Emma Magavern from William Harvey Research Institute analysed over 1.3 million ADR reports submitted to the MHRA Yellow Card scheme. It found that 115,789 (9%) were associated with drugs for which side effect risk can be modified using pharmacogenomics (PGx) information to guide prescribing. Of these, 75% were associated with three genes that affect the way an individual processes medication (CYP2C19, CYP2D6, SLCO1B1).
The type of medications that showed the highest volume of ADRs that could be prevented by personalising prescribing with genetic information were treatments for psychiatric disorders (47%) and cardiovascular problems (24%). The study also found that patients who had ADRs which were able to be mitigated by PGx were more likely to be male, older, and to experience side-effects that were severe but non-fatal.
Clinical trials have shown that using genetic information to guide prescribing pre-emptively, such as adjusting the dose or choosing different medication, can avoid ADRs and improve patient outcomes. This research highlights the potential of integrating pharmacogenomic testing into clinical practice to make medicines safer and more effective for patients.
