Pharmacogenomics: Personalised Medicine and Genetic Variation

Introduction: Pharmacogenomics is the study of how a person's genetic makeup influences their response to medicines, including drug effectiveness, metabolism and the risk of adverse reactions.

Key pointers

  • Core concept: Uses genetic information to help guide medicine selection and dosing.

  • Genetic variation: Differences in genes can alter drug-metabolising enzymes, transporters and drug targets.

  • Clinical application: May help identify the most appropriate medicine or dose for certain patients.

  • Drug metabolism: Genes in the cytochrome P450 family, including CYP2D6 and CYP2C19, influence the metabolism of several medicines.

  • Example: CYP2C19 genetic variation can affect a patient's response to clopidogrel.

  • Adverse drug reactions: Genetic testing can identify some patients at increased risk of particular drug reactions.

  • Distinction from pharmacogenetics: Pharmacogenetics often focuses on individual gene–drug relationships, whereas pharmacogenomics may consider broader genomic influences.

  • Benefits: Supports more individualised treatment and may reduce avoidable adverse reactions.

  • Limitations: Genetic factors are only part of the picture; age, organ function, diet, other medicines and disease conditions also influence drug response.

  • Public-health relevance: Important for precision medicine and the development of clinically guided genetic testing.

UPSC focus: Pharmacogenomics connects genetics with pharmacology. It is different from pharmacovigilance, which focuses on detecting, assessing and preventing adverse effects associated with medicines.