CYP2C9 and Meloxicam

Normal Metabolizer

Clinical Implication

  • Normal CYP2C9 enzyme activity.
  • Normal response expected.

Therapeutic Recommendation

  • Initiate therapy with recommended starting dose.
  • In accordance with the prescribing information, use the lowest effective dosage for shortest duration consistent with individual patient treatment goals.

Intermediate Metabolizer with an enzyme Activity Score of 1.5

Clinical Implication

  • Decreased CYP2C9 enzyme activity.
  • Slightly increased risk of adverse events (e.g., GI bleed, cardiovascular).

Therapeutic Recommendation

  • Initiate therapy with recommended starting dose.
  • In accordance with the prescribing information, use the lowest effective dosage for shortest duration consistent with individual patient treatment goals.

Intermediate Metabolizer with an enzyme Activity Score 1

Clinical Implication

  • Decreased CYP2C9 enzyme activity.
  • Increased risk of adverse events (e.g., GI bleed, cardiovascular).

Therapeutic Recommendation

  • Initiate therapy with a 50% initial dose reduction and titrate slowly, up to 50% of the maximum recommended dose. Allow at least one week between dose titrations. OR…
  • Choose an alternative non-NSAID pain medication not metabolized by CYP2C9 (e.g. acetaminophen). OR…
  • If an NSAID is indicated, ibuprofen, celecoxib, or flurbiprofen can be used at the lowest starting dose and titrated. Other NSAIDs not metabolized by CYP2C9 can be used at standard doses (e.g., aspirin, ketorolac, naproxen, and sulindac).
  • In accordance with the prescribing information, use the lowest effective dosage for shortest duration consistent with individual patient treatment goals.

Poor Metabolizer

Clinical Implication

  • Little to no CYP2C9 enzyme activity.
  • Increased risk of adverse events (e.g., GI bleed, cardiovascular).

Therapeutic Recommendation

  • Choose an alternative non-NSAID pain medication not metabolized by CYP2C9 (e.g. acetaminophen). OR…
  • If an NSAID is indicated, ibuprofen, celecoxib, or flurbiprofen can be used with a 25-50% initial dose reduction and slow titration up to 50% of the maximum recommended dose. Other NSAIDs not metabolized by CYP2C9 can be used at standard doses (e.g., aspirin, ketorolac, naproxen, and sulindac).
  • In accordance with the prescribing information, use the lowest effective dosage for shortest duration consistent with individual patient treatment goals.

Unable to Genotype or Assay Failure

  • The analysis failed to yield an informative result and thus no genotype is reported.

Unknown Phenotype

  • This individual is carrying at least one allele with uncertain/unknown function and the predicted phenotype cannot be determined at this time.

Reference

  • Theken KN et al. Clin Pharmacol Ther. 2020 Aug;108(2):191-200. PMID: 32189324.

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