How PGx Works
Pharmacogenomics studies how genetic variations affect how the body processes and responds to drugs. Key genetic variants affect drug-metabolizing enzymes — proteins that break down drugs in the body. A patient who is a "poor metabolizer" of a drug may experience toxicity at standard doses; an "ultra-rapid metabolizer" may not achieve therapeutic levels. PGx testing identifies these variants before prescribing.
High-Impact PGx Drug-Gene Pairs
| Drug | Gene | Clinical Impact |
|---|---|---|
| Clopidogrel (Plavix) | CYP2C19 | Poor metabolizers have 3x higher cardiovascular event risk |
| Codeine | CYP2D6 | Ultra-rapid metabolizers risk fatal toxicity |
| Warfarin | CYP2C9/VKORC1 | Variants affect optimal dose by 2–5x |
| Tamoxifen | CYP2D6 | Poor metabolizers have reduced cancer protection |
| Antidepressants (SSRIs) | CYP2D6/CYP2C19 | Variants affect efficacy and side effects |
The Failed Medication Cycle
IQ Insight
The average psychiatric patient tries 3–4 medications before finding one that works — a process that takes 12–18 months and costs $10,000–$20,000 in medication and office visit costs. PGx testing can identify which medications are likely to work for a specific patient based on their genetic profile — reducing the failed medication cycle and improving outcomes.