Why Your DNA Should Guide Your Prescription: The Pharmacogenomics Revolution
One of the most common frustrations in psychiatry — for patients and providers alike — is the trial-and-error nature of prescribing. A patient tries an antidepressant for 6 weeks. It doesn't work. They try another. Side effects. Another. Finally, after months or years, something sticks. Pharmacogenomics is fundamentally changing this process.
What Is Pharmacogenomics?
Pharmacogenomics is the study of how a person's genetic makeup affects their response to medications. In psychiatry, we focus on genes encoding the cytochrome P450 (CYP450) enzyme system, which metabolizes the vast majority of psychiatric drugs in the liver. Variants in genes like CYP2D6, CYP2C19, and CYP3A4 determine whether a person is a poor, intermediate, normal, or ultra-rapid metabolizer of specific drug classes.
🧬 The Scale: Over 90% of people carry at least one clinically actionable pharmacogenomic variant. Yet most psychiatric prescriptions are written without this information — meaning the majority of patients receive "best guesses."
A Concrete Example: SSRIs and CYP2C19
Escitalopram (Lexapro) and citalopram (Celexa) are primarily metabolized by CYP2C19. Poor metabolizers accumulate drug at higher levels, experiencing significant side effects at standard doses. Ultra-rapid metabolizers break the drug down so quickly it never reaches therapeutic levels — leaving them feeling "like it just didn't work." Without a pharmacogenomic test, a prescriber has no way of knowing which category their patient falls into. With a simple cheek swab, they do — before writing the first prescription.
How Testing Works at UMG
A cheek swab collected during your appointment is sent to a specialized lab. Results return in 5–7 business days as a comprehensive report mapping your genetic variants to specific medications — flagging drugs to use, use with caution, or avoid. Dr. Punia and our team then translate this data into a concrete, personalized treatment plan.
Is It Covered by Insurance?
Many major plans, including Medicare and Medi-Cal, cover pharmacogenomic testing when medically necessary — particularly for patients with documented treatment resistance or adverse drug reactions. Our billing team handles preauthorization and can advise on your plan's coverage before testing.
Get Expert Care at UMG
Available at both our Pleasant Hill and Vallejo locations. Can be ordered alongside your initial evaluation or any follow-up visit.
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