What is Pharmacogenomics?
Pharmacogenomics means studying how a person’s genes (DNA) affect their response to medicines.
Because of gene differences, the same drug dose can be:
- Safe for one person
- Too strong (toxic) for another
- Not effective for someone else
Role of Pharmacogenomics in ADRs:
Pharmacogenomics helps in predicting, preventing, and reducing ADRs by identifying patients who are genetically at risk.
1) Predicts high-risk patients
Some people have gene variants that make them more likely to develop side effects. So, doctors can identify risk before giving the drug.
Example:
HLA-B*1502 → high risk of severe skin reactions with Carbamazepine (common in Asians)
2) Explains why ADRs happen
ADRs often occur because the drug stays longer in the body or becomes too concentrated.
This happens when genes affecting drug metabolism are different.
Example:
CYP2D6 poor metabolizers → higher levels of drugs like codeine/antidepressants, causing toxicity.
3) Helps in dose adjustment (Personalized dose)
Pharmacogenomics helps choose the correct dose based on gene type.
Example:
Warfarin dose depends on genes like CYP2C9 and VKORC1 Wrong dose → bleeding risk (ADR)
4) Prevents life-threatening ADRs
Some ADRs are serious like:
Stevens-Johnson Syndrome (SJS)
Toxic Epidermal Necrolysis (TEN)
Severe bleeding
Bone marrow suppression
Pharmacogenomic testing can prevent these.
Example:
TPMT gene deficiency + Azathioprine/6-MP → severe bone marrow suppression
5) Improves drug safety in clinical practice by using genetic testing: - safer prescribing
- fewer hospitalizations
- better patient outcomes
MBH/PS