Impact of genetic variation on response to therapy
Meloxicam metabolism is primarily mediated via CYP2C9 enzymes. The activity of CYP2C9 enzymes is influenced by genetic variation in the CYP2C9 gene which can have an impact on drug exposure and the risk of adverse drug reactions.
CYP2C9 poor metabolisers are expected to have markedly reduced metabolism and an increase in plasma concentrations of meloxicam compared to normal metabolisers. This may increase the probability or severity of adverse drug reactions. Meloxicam adverse drug reactions include gastrointestinal bleeding, cardiotoxicity, hypertension, and nephrotoxicity.
Due to its long half-life compared to other commonly used NSAIDs such as ibuprofen, impaired meloxicam metabolism is expected to cause sustained increases in drug exposure. The Clinical Pharmacogenetics Implementation Consortium (CPIC®) reports an increase in meloxicam AUC of approximately 80% in CYP2C9 intermediate metabolisers with an activity score of 1, and that in CYP2C9 poor metabolisers a markedly prolonged half-life (>100 hours) is expected.
Testing recommendations
At the time of publication there are no UK recommendations for CYP2C9 genotype testing to guide the use of meloxicam.
Therapeutic recommendations
CYP2C9 metaboliser status unknown
- Initiate treatment with standard dose and titrate according to response.
- Use the lowest effective dose for the shortest duration necessary to control symptoms.
CYP2C9 Normal metabolisers: Activity score 2.0
Some examples of CYP2C9 genotypes include: *1/*1
- Initiate treatment with standard dose and titrate according to response.
- Use the lowest effective dose for the shortest duration necessary to control symptoms.
CYP2C9 Intermediate metabolisers: Activity score 1.5
Some examples of CYP2C9 genotypes include: *1/*2
- Mildly reduced metabolism compared to normal metabolisers.
- Increased plasma concentrations may increase risk of adverse drug reactions.
- Initiate treatment with standard dose and titrate according to response.
- Use the lowest effective dose for the shortest duration necessary to control symptoms.
CYP2C9 Intermediate metabolisers: Activity score 1.0
Some examples of CYP2C9 genotypes include: *1/*3, *2/*2
- Moderately reduced metabolism compared to normal metabolisers.
- Sustained increases in plasma concentrations may increase risk of adverse drug reactions.
- Initiate treatment with 50% of the lowest recommended starting dose and titrate cautiously according to response to no more than 50% of the maximum recommended dose.
- Wait until steady state is reached before titrating the dose (at least 7 days).
- Use the lowest effective dose for the shortest duration necessary to control symptoms and monitor for adverse drug reactions.
- Alternatively, consider a therapy without significant CYP2C9 metabolism or with a shorter half-life, especially if additional risk factors for NSAID toxicity are present (see Further information).
CYP2C9 Poor metabolisers: Activity score 0.5 or 0.0
Some examples of CYP2C9 genotypes include: *2/*3, *3/*3
- Greatly reduced metabolism compared to normal metabolisers.
- Sustained increases in plasma concentrations may increase risk and severity of adverse drug reactions.
- Choose an alternative therapy without significant CYP2C9 metabolism or with a shorter half-life.
Further information
Meloxicam metabolism and drug interactions
Meloxicam is eliminated almost exclusively by hepatic metabolism, for which approximately two thirds is mediated by CYP enzymes (mainly CYP2C9 and to a minor extent CYP3A4). The SmPC states that interactions must be considered when meloxicam is administered concomitantly with medicinal products known to inhibit, or to be metabolised by CYP2C9 and/or CYP3A4. The impact of drug interactions with meloxicam may be more pronounced in people with reduced CYP2C9 activity. Consult the SmPC for more detailed information on drug interactions.
Additional risk factors for NSAID toxicity
The impact of genetic variation should be considered alongside additional individual risk factors for adverse drug reactions with NSAIDs, such as older age, drug interactions, and co-morbidities. Consult the SmPC for further details of additional risk factors.
Alternative NSAIDs in CYP2C9 intermediate or poor metabolisers
Alternative NSAIDs not known to be significantly impacted by CYP2C9 variation include naproxen, diclofenac and aspirin. NSAIDs metabolised by CYP2C9 but with a shorter half-life include ibuprofen, flurbiprofen and celecoxib. See individual drug monographs for further information.
References
Flamingo Pharma (UK) Ltd (2025). Meloxicam 15mg Tablets SmPC. Available at: https://www.medicines.org.uk/emc/product/101306/smpc Accessed online 15th April 2026.
Clinical Pharmacogenetics Implementation Consortium CPIC® (2020) Guideline for CYP2C9 and Nonsteroidal Anti-Inflammatory Drugs. Available at: https://www.clinpgx.org/guideline/PA166251464 Accessed online 15th April 2026.
