Pharmacogenetics looks at how your genes shape your response to painkillers and other medicines. In spine surgery and chronic pain, it can help choose the safest drug and dose, especially with opioids (codeine, tramadol, oxycodone) and some anti-inflammatories. This guide, in plain language, outlines when it may help, which genes are commonly tested, and what practical choices can follow from a report.
What is pharmacogenetics and why does it matter in spine surgery?
It links genetic variation to how medicines work. For postoperative and chronic pain, certain enzymes (such as CYP2D6 or CYP2C9) and receptors (such as OPRM1) can make the same drug ineffective in some people and more prone to side effects in others. It doesn’t replace clinical judgement; it adds one more piece to personalize care.
Who might benefit? Common symptoms and indications
- Pain that remains poorly controlled despite “usual” doses.
- Notable side effects with analgesics (severe nausea, excessive sleepiness, dizziness, confusion).
- Past reactions to codeine/tramadol or other opioids.
- Use of multiple medicines at once (higher interaction risk).
- Planned surgery where it’s wise to prevent pain-control problems and side effects from the start.
How is the test done and which genes are analyzed?
Most tests use a saliva or blood sample. Typical panels include:
- CYP2D6: affects activation of codeine and tramadol and can influence responses to other opioids.
- CYP2C9: involved in the metabolism of NSAIDs such as ibuprofen, naproxen, or celecoxib.
- OPRM1: encodes the μ-opioid receptor; some variants relate to different sensitivity.
- COMT: linked to pain perception and the effects of certain analgesics.
The laboratory reports a phenotype (for example, “poor” or “ultra-rapid” metabolizer) and suggests precautions. Your clinical team integrates that with your history and goals.
Alternatives and how they fit with pharmacogenetics
Pain care follows a stepwise approach: pain education, cold/heat, physiotherapy, graded exercise, non-opioid medicines, and—if needed—opioids at the lowest effective dose for the shortest time. Pharmacogenetics doesn’t pick a “perfect” drug; it helps prioritize options and fine-tune dosing more safely.
Typical clinical decisions based on a report (examples)
- Codeine and tramadol: if the report shows a CYP2D6 “poor metabolizer,” these drugs may not relieve pain. Consider alternatives that don’t rely on that pathway or adjust the strategy.
- Opioids such as oxycodone: CYP2D6 phenotype can modulate response; monitor efficacy and side effects closely and adjust carefully.
- NSAIDs and CYP2C9: some profiles suggest lower doses or choosing different NSAIDs, especially with gastrointestinal/renal risk.
- Adjuvants (e.g., antidepressants or antiepileptics for neuropathic pain): depending on the panel, starting with lower doses and slow titration may be recommended.
Benefits, limits, and adverse effects
Potential benefits: fewer unwanted effects, a higher chance of earlier relief, less trial-and-error, and more precise follow-up.
Limits: not all drugs have robust guidance; two people with the same genotype can still respond differently; testing never replaces a full clinical assessment.
When to refer or seek specialist input
- Ongoing, life-limiting pain after the expected recovery period.
- Significant or repeated side effects with several analgesics.
- Need for combination or long-term treatments.
- Family history of unusual drug reactions.
Recovery timelines: setting realistic expectations
After spine surgery, many people improve over days to weeks. Planning analgesia early (with or without pharmacogenetics) aims to make the first 2–4 weeks safer and more manageable. Guided activity and scheduled follow-up matter as much as the drug choice.
When to go to the emergency department
- Marked drowsiness, slow breathing, or breathing pauses after taking opioids.
- Confusion, fainting, persistent vomiting, or widespread itching/hives.
- Sudden, worsening pain; high fever; progressive weakness; or loss of bladder/bowel control.
Myths and facts
- Myth: “Genes decide everything.” Fact: they guide choices but don’t replace clinical assessment.
- Myth: “If I’m ultra-rapid, I just need higher doses.” Fact: toxicity risk may rise; a different approach may be safer.
- Myth: “Testing means I won’t have side effects.” Fact: risks can be reduced, never reduced to zero.
Frequently asked questions
Is the test mandatory before surgery?
No. It’s optional. It may help if you’ve had poor pain control or side effects with analgesics, or if complex treatments are expected.
When is it done: before or after surgery?
It can be ordered preoperatively or in a pain clinic if control is difficult. The decision is individualized.
Will it guarantee better pain relief?
No guarantees, but it reduces trial-and-error and supports safer choices.
Does it apply to all medicines?
No. Evidence is stronger for certain opioids and some NSAIDs. Elsewhere, recommendations are more cautious.
Is it a one-time test?
Usually yes. Your genotype doesn’t change; the report can be reused later.
Could it affect my privacy?
It must be managed with informed consent and in line with data-protection regulations.
Glossary
- CYP2D6/CYP2C9: liver enzymes that metabolize many drugs.
- OPRM1: gene for the μ-opioid receptor.
- Phenotype: how your metabolism “behaves” based on your genotype (e.g., poor/rapid metabolizer).
- NSAID: non-steroidal anti-inflammatory drug.
References
- Dr. Vicenç Gilete – Pharmacogenetics in precision medicine
- Spanish Pain Society Journal (2023): pharmacogenetics and analgesic response
- La Princesa University Hospital (2021): opioid adjustment by CYP2D6
- Ministry of Health (2025): safe opioid use
- FDA: table of pharmacogenetic associations
- Update in pharmacogenetics (2025): overview of CPIC guidance
Important notice: This material is educational and does not replace care by a licensed healthcare professional.
