Is Strefen affected by genetics?
Yes. Its active ingredient has published pharmacogenetic guidance for a gene that varies between people.
Strefen is affected by pharmacogenetics through the CYP2C9 gene. Your genotype for this gene can change how well Strefen works for you or how well you tolerate it. The strongest evidence level on this page is Strong, from the published guidelines shown below.
What's in Strefen
Flurbiprofen Affected by CYP2C9
Affected by CYP2C9. Guidance from CPIC, FDA, strong evidence.
Read the full flurbiprofen genetics guideFlurbiprofen phenotype recommendations
Published guidance from CPIC and FDA on how flurbiprofen should be dosed or substituted based on your CYP2C9 phenotype.
| Phenotype | What it means | Recommendation | Evidence |
|---|---|---|---|
| Normal MetabolizerCYP2C9 | Your body processes this drug normally, so the usual starting dose applies. | CPIC Initiate therapy with recommended starting dose. In accordance with the prescribing information, use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. FDA Initiate therapy with recommended starting dose. |
Strong |
| Intermediate Metabolizer AS of 1.5CYP2C9 | Your body slows the drug down slightly, but usually the normal starting dose is fine. | CPIC Initiate therapy with recommended starting dose. In accordance with the prescribing information, use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. |
Moderate |
| Intermediate Metabolizer AS of 1CYP2C9 | Your body clears this drug more slowly. It's best to start at the lowest dose and raise it with care if needed. | CPIC Initiate therapy with lowest recommended starting dose. Titrate dose upward to clinical effect or maximum recommended dose with caution. In accordance with the prescribing information, use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. Carefully monitor adverse events, such as blood pressure and kidney function, during course of therapy. |
Moderate |
| Poor MetabolizerCYP2C9 | Your body clears this drug very slowly, so it can build up. A much lower starting dose, or a different drug, is suggested. | CPIC + CPIC Initiate therapy with 25 to 50% of the lowest recommended starting dose. Titrate dose upward to clinical effect or 25 to 50% of the maximum recommended dose with caution. In accordance with the prescribing information, use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. Upward dose titration should not occur until after steady-state is reached (at least 8 days for celecoxib and 5 days for ibuprofen, flurbiprofen, and lornoxicam after first dose in PMs). Carefully monitor adverse events such as blood pressure and kidney function during course of therapy. Alternatively, consider an alternate therapy not metabolized by CYP2C9 or not significantly impacted by CYP2C9 genetic variants in vivo. FDA Use a reduced dosage. |
Strong |
| IndeterminateCYP2C9 | The impact of your genotype on response to this drug is unknown. | CPIC + FDA Initiate therapy with recommended starting dose. |
Not rated |
| Not availableCYP2C9 | The impact of your genotype on response to this drug is unknown. | CPIC + FDA Initiate therapy with recommended starting dose. |
Not rated |
| Intermediate MetabolizerCYP2C9 | Your body may break down this drug a little slower than average. The FDA label gives no dose change for your result. | FDA Initiate therapy with recommended starting dose. |
Not rated |
The gene behind the guidance
CYP2C9 Cytochrome P450 2C9
CYP2C9 metabolizes warfarin, phenytoin, celecoxib, and some NSAIDs. Variants that reduce its activity are most consequential for warfarin, where even small changes in drug clearance translate into very different doses (and a real bleeding risk if missed).
Poor metabolizers need substantially lower warfarin doses to hit the same INR target.
See all drugs affected by CYP2C9Browse the full drug class: Pain medications.
Related medications
Find out how your genetics affect Strefen
Informational only, not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.