Dr. Patricia Cammazola doesn’t think so.
“Physicians/prescribers are often not aware of the liability associated with not considering PGx FDA recommendations and CPIC guidelines for commonly used medications.”
That warning may sound academic, but it’s anything but. With the FDA publishing pharmacogenomic (PGx) biomarker recommendations for over 400 medications, and organizations like CPIC issuing actionable, evidence-based dosing guidelines, the bar for responsible prescribing is shifting. And those who ignore it could be exposing themselves, plus their patients, to unnecessary harm and rising legal risk.
According to The FDA, PGx Isn’t Optional for Some Drugs
The FDA maintains a dynamic list of drugs with pharmacogenomic labeling: medications where gene-drug interactions are clinically significant. These aren’t fringe treatments, as many might assume (watch for our upcoming blog on why warfarin is the PGx poster child). Some are blockbusters prescribed every day in cardiology, psychiatry, pain management, and oncology. A few examples:
- Clopidogrel (Plavix): For patients with a poor metabolizer CYP2C19 genotype, the drug may not work as intended—putting them at risk for heart attacks or strokes.
- Codeine and Tramadol: The CYP2D6 gene determines how quickly these opioids are metabolized. Ultra-rapid metabolizers can suffer from life-threatening respiratory depression.
- Abacavir: The HLA-B*57:01 allele is a known marker for potentially fatal hypersensitivity reactions. The FDA mandates testing before prescribing.
- Simvastatin: Certain SLCO1B1 gene variants can lead to a higher risk of muscle toxicity (myopathy).
In some cases, the FDA even includes boxed warnings, aka the agency’s strongest caution, tied directly to a patient’s genetic profile.
Where PGx Testing Makes a Difference
Pharmacogenomic testing is about delivering safer, more precise care. Clinical areas where PGx should be strongly considered include:
| Specialty | Medication Example | Relevant Gene(s) |
| Cardiology | Clopidogrel | CYP2C19 |
| Psychiatry | SSRIs, TCAs, Antipsychotics | CYP2C19, CYP2D6 |
| Pain Management | Codeine, Tramadol | CYP2D6 |
| Infectious Disease | Abacavir | HLA-B*57:01 |
| Oncology | 6-MP, Azathioprine | TPMT, NUDT15 |
| Lipid Disorders | Simvastatin | SLCO1B1 |
What Happens if Prescribers Ignore This?
As pharmacogenomics edges closer to the standard of care, ignoring FDA guidance could have consequences, not just for patient outcomes but in courtrooms. In fact, malpractice claims related to adverse drug reactions are among the most common in the U.S., and as PGx testing becomes more accessible, legal expectations are rising.
So far, there’s no record of a physician being sued specifically for failing to follow PGx guidelines. But we’re not far off. There are already precedents:
- A child’s death from codeine after surgery, linked to CYP2D6 ultra-rapid metabolism, prompted an FDA black box warning.
- A lawsuit was filed when a patient of Asian descent developed life-threatening Stevens-Johnson syndrome from carbamazepine, despite FDA recommendations to test for HLA-B*15:02.
When Insurance Says No
Here’s another bitter truth that Dr. Cammazola points out:
“If a service is not covered by insurance, it is not viewed as a priority or necessity by prescribers or patients, i.e. the payors are determining how medicine is practiced.”
Even when prescribers want to use PGx to improve patient outcomes, lack of reimbursement can be a major roadblock. And when insurers don’t pay, patients often decline the test. Unfortunately, this creates a feedback loop—where the failure to prioritize PGx isn’t based on science, but on billing codes.
This is especially dangerous with medications that carry serious gene-drug risks. The result? Liability rests with the prescriber, not the insurer.
So What Should Prescribers Do?
- Check the FDA’s Pharmacogenetic Biomarker Table before prescribing high-risk medications.
- Consult CPIC guidelines when patients have known genotypes or test results.
- Document your decisions, especially when you deviate from FDA or CPIC recommendations.
- Educate patients on the value of PGx testing, especially if they’re paying out of pocket.
