Pharmacogenomics in primary care: a quality improvement project at Alconbury and Brampton surgeries 2019–2023

Background Treatment of depression is common in primary care but not every antidepressant is effective in every patient. Adverse drug reactions are common, imposing a substantial burden on the patient and the NHS. Pharmacogenomics (PGx) utilises an individual’s genetic makeup to predict their response to medications. By tailoring prescriptions to a person’s genetic profile, PGx can significantly reduce adverse drug reactions, identify non-responders to medications, and enhance overall patient outcomes. Aim To see if PGx testing for antidepressants can be undertaken in general practice as part of ‘usual care’; to increase GP and patient awareness of PGx testing; to alter patient treatment according to the results of testing; and to sustain these changes at 4 years. Method In 2019, 23 patients were recruited by GPs at the surgery. They consented and had cheek swabs to check their genetic profile to common antidepressants. Results were reviewed at 1 week by the GP and patient, treatment changes made and reviewed again at 4 years. Results On the CYP2D pathway, 19/23 patients were extensive (normal) metabolisers, one intermediate and two poor. These two had their treatments changed. At 4-year review 19/23 were on appropriate treatment (two had been stopped) but two had inappropriate drug treatment. On CYP2C19 pathway, 10/23 were normal metabolisers, eight intermediate, zero poor but five ultrarapid (they had their treatment changed). At 4-year review, 20/23 were on appropriate treatment (two stopped) and one inappropriate. Conclusion PGx testing works in primary care, improving patient outcomes sustainably.