On the horizon: Pharmacogenomics

We all want to believe that the medicines our doctors prescribe will work to help us recover and that by taking these medicines we will not experience unpleasant effects. However, it’s estimated that only 25-60% of people get a good response from their medicines. For example, a patient seeking advice for depression symptoms will be prescribed a first-line antidepressant. For some patients these medicines will work quite effectively, however, for others, it can take 2-3 months before they begin to work.  With such a long interval, patients may become discouraged and even stop taking their medicines. Furthermore, some patients may experience side effects and consequently have to visit their GP multiple times to try different medicines before they reach the right medicine for their depression.

Scientific discoveries have led to the development of a test that could help the GP decide which is the best medicine to prescribe thereby reducing the trial-and-error aspect of prescribing and risks of side effects. These tests are known as pharmacogenomic tests.

What exactly is pharmacogenomics?

The word pharmacogenomics is derived from pharmaco- + genomics, with pharmaco- pertaining to medicines and genomics being the study of the body’s genes. Pharmacogenomics is the study of how an individual’s genetic makeup (genes) influences their response to medicines. A person’s genetic makeup can determine how a drug is broken down (or metabolised) in the body. By undertaking a simple pharmacogenomic test, which could be a saliva swab or a blood sample, information can be obtained on how a person may react to certain drugs.

Some people will be classed a slow metaboliser of medicines, some people are normal metabolites, whilst others are classed as rapid/ultra-rapid metabolisers. Slow metabolisers break down medicines slowly in the body, resulting in build-up and exposure to unpleasant effects of the medicine. Rapid/ultra-rapid metabolisers on the other hand remove medicines more quickly from the body and the medicine does not exhibit the desired effects.

Traditionally these tests have been used by specialists to help guide prescribing for certain conditions such as cancer. However, pharmacogenomic tests are becoming more common and can help primary care professionals (such as GPs, pharmacists, or nurses) to prescribe the right medicine the first time for common conditions such as depression, pain management and diabetes. Countries such as the USA, Canada and The Netherlands are leading the use of pharmacogenomic tests in primary care to help to prescribe. The UK is currently embarking on its genomic journey, with several initiatives being rolled out across the country, focusing on conditions such as cancer initially. But within the next 5-10 years, pharmacogenomic testing is expected to be more routine in the NHS to aid prescribing.

Can pharmacogenomics help reduce inequalities?

Health inequalities exist between Black, Asian and minority ethnic (BAME) and other groups. Indeed the prevalence of anxiety and depression in south Asian women is 64% compared with white women at 29%. Pharmacogenomic tests could therefore be particularly useful for BAME communities, where long term conditions such as diabetes are so prevalent and help in reducing unnecessary adverse effects from medicines.

Islam teaches us to continuously seek knowledge and use that knowledge for the benefit of mankind. The creation of humanity is raised above many other creations and one distinct feature of humans is the ability to reflect, ponder and learn. It is incumbent on us therefore to learn more so we can take advantage of these medical developments. Knowledge gained through understanding a person’s genetic makeup will benefit us all, but especially those people who may be more affected by such conditions.