CYP2C19 and Omeprazole, Pantoprazole, Lansoprazole, Dexlansoprazole

Ultrarapid Metabolizer

Clinical Implication

  • Increased CYP2C19 enzyme activity.
  • Increased risk of treatment failure.

Therapeutic Recommendation

  • Increase PPI dose by 2 times the standard daily dose.

Rapid Metabolizer

Clinical Implication

  • Increased CYP2C19 enzyme activity.
  • Increased risk of treatment failure.

Therapeutic Recommendation

  • For H. pylori infection or erosive esophagitis, increase PPI dose by 1.5-2 times the standard daily dose.
  • For all other indications, initiate standard starting daily dose and increase dose for inadequate response.

Normal Metabolizer

Clinical Implication

  • Normal CYP2C19 enzyme activity.
  • Normal response expected, unless treating H. pylori or erosive esophagitis, then increased risk of treatment failure.

Therapeutic Recommendation

  • For H. pylori infection or erosive esophagitis, increase PPI dose by 1.5-2 times the standard daily dose.
  • For all other indications, initiate standard starting daily dose.

Intermediate Metabolizer

Clinical Implication

  • Decreased CYP2C19 enzyme activity.
  • Increased risk of adverse effects (e.g., infections, electrolyte imbalance, bone fractures) with chronic use (>12 weeks).

Therapeutic Recommendation

  • For chronic therapy, consider a 50% dose reduction once symptoms are controlled.

Poor Metabolizer

Clinical Implication

  • No CYP2C19 enzyme activity.
  • Increased risk of adverse effects (e.g., infections, electrolyte imbalance, bone fractures) with chronic use (>12 weeks).

Therapeutic Recommendation

  • For chronic therapy, consider a 50% dose reduction once symptoms are controlled.

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

  • Lima JJ et al. Clin Pharmacol Ther. 2021 Jun;109(6):1417-1423. PMID: 32770672.

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