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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