Meloxicam is a nonsteroidal anti-inflammatory drug (NSAID) commonly marketed under brand names such as Mobic. It is prescribed to reduce pain and inflammation.
This medication is used to treat chronic conditions such as osteoarthritis and rheumatoid arthritis, helping improve joint function and reduce symptoms.
Meloxicam works by preferentially inhibiting the cyclooxygenase-2 (COX-2) enzyme, leading to decreased synthesis of prostaglandins—substances that trigger pain, swelling, and fever.
The primary gene affecting meloxicam metabolism is CYP2C9.
CYP2C9 is a liver enzyme responsible for breaking down many NSAIDs, including meloxicam. Genetic variants in CYP2C9 can alter enzyme activity and change how quickly meloxicam is cleared from the body. In pharmacogenomics, a “metabolizer” category describes how efficiently your body processes a drug—normal metabolizers process medications at an expected rate, while poor metabolizers break them down much more slowly.
Variations in CYP2C9 activity classify individuals into phenotypes—normal, intermediate, or poor metabolizers—which influence meloxicam blood levels. Intermediate metabolizers may have modestly higher drug exposure, while poor metabolizers can experience significantly prolonged drug clearance, increasing the risk of adverse effects. Indeterminate or unavailable genotypes default to standard dosing with careful clinical monitoring.
The following dosing guidelines are based on the available recommendations for CYP2C9 from CPIC.
| Phenotype | Clinical Consequence | Guideline Recommendation |
|---|---|---|
| Normal Metabolizer | Normal metabolism | 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. |
| Intermediate Metabolizer (activity score 1.5) | Mildly reduced metabolism | Initiate therapy with recommended starting dose. In accordance with the meloxicam prescribing information, use the lowest effective dosage for the shortest duration consistent with individual patient treatment goals. |
| Intermediate Metabolizer (activity score 1.0) | Moderately reduced metabolism; higher plasma concentrations may increase probability of toxicities | Initiate therapy with 50% of the lowest recommended starting dose. Titrate dose upward to clinical effect or 50% of the maximum recommended dose with caution. In accordance with the meloxicam 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 7 days). Carefully monitor adverse events, such as blood pressure and kidney function, during course of therapy. Alternatively, consider alternative therapy. Choose an alternative therapy not metabolized by CYP2C9 or not significantly impacted by CYP2C9 genetic variants in vivo, or choose an NSAID metabolized by CYP2C9 but with a shorter half-life. |
| Poor Metabolizer | Significantly reduced metabolism and prolonged half-life; higher plasma concentrations may increase probability and/or severity of toxicities | Choose an alternative therapy not metabolized by CYP2C9 or not significantly impacted by CYP2C9 genetic variants in vivo, or choose an NSAID metabolized by CYP2C9 but with a shorter half-life. |
| Indeterminate/Not available | Unknown impact | Initiate therapy with recommended starting dose. |
Examples from guideline recommendations include choosing an NSAID not metabolized by CYP2C9 or one with a shorter half-life (e.g., celecoxib) or using non-NSAID analgesics such as acetaminophen. These are guideline examples and not medical advice.
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