When the same drug is given at the same dose, marked differences in efficacy and side effects can be seen between people. A significant part of this difference comes from inherited changes in the genes that encode the enzymes and transporter proteins that metabolize drugs. Pharmacogenetics is the field that studies this relationship.
Commonly studied genes
- CYP2C19, clopidogrel, some antidepressants and proton pump inhibitors
- CYP2D6, some antidepressants, antipsychotics and painkillers
- CYP2C9 / VKORC1, warfarin dose adjustment
- TPMT / NUDT15, thiopurine drugs
What does the test provide?
The result shows whether the person is a "rapid", "normal", "intermediate" or "poor metabolizer" for the enzyme in question. This information can help in choosing an alternative drug, adjusting the starting dose or monitoring more closely. Pharmacogenetic results remain valid for life and can be used in future treatment decisions as well.
Test results must always be evaluated together with the prescribing physician; current treatment should not be changed without the physician's approval.
