by Dr Mark J Hudson-Peacock, BSc(Hons), MBBCh, FRCP, MIoD – Consultant Dermatologist and Founder/CEO of Mantara Health Ltd
Pharmacogenomics (PGx) is the study of how a person’s genetic makeup influences their response to medication. While many medicines are effective for large numbers of people, others may provide limited benefit, cause unwanted side effects, or require multiple changes before the right option is found. These differences are not random. In many cases, they are influenced by genetic variation. PGx aims to understand these differences and use them to support more informed prescribing decisions from the outset of a patient’s care.
Many commonly prescribed medicines are processed by enzymes in the body that are encoded by specific genes. Variations in these genes can affect how quickly or slowly a drug is metabolised. Some individuals break down medicines very rapidly, meaning the drug may not reach effective levels. Others metabolise medicines more slowly, increasing the likelihood of side effects or adverse reactions. PGx testing identifies these genetic differences, allowing clinicians to consider both medicine choice and dosing in a way that better reflects an individual’s biology.
This approach is particularly relevant in clinical areas where medication response varies widely. In mental health, PGx can help support decisions around antidepressants and other psychotropic medications, where trial-and-error prescribing is common. In cardiology, genetic variation can influence the effectiveness of antiplatelet and other cardiovascular medicines. PGx is also increasingly relevant in pain management, oncology and primary care, where anticipating treatment response can help reduce delays and improve patient experience.
Importantly, PGx does not replace clinical judgement. Instead, it provides an additional layer of insight that can be used alongside clinical history, physical assessment and patient preferences. By offering information on how a patient is likely to respond before treatment begins, PGx supports safer, more personalised and more efficient care.
As healthcare continues to move towards a more personalised model, pharmacogenomics represents a practical and evidence-based step forward. For clinicians interested in learning more about how PGx can be integrated into routine practice, further information and educational resources are available at Mantara Health.