Metabolism

Cytochrome P-450 2C19 Isoenzyme

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Cytochrome P-450 2C19 Isoenzyme, CYP2C19, CYP2C19 Inducer, CYP2C19 Inhibitor, CYP2C19 Substrate

  • See Also
  1. CYP2C9
  1. See Pharmacogenetics
  2. Poor metabolizers (2-15%, 20% in asians)
    1. Clopidogrel with reduced conversion to active form (higher risk for stent closure)
    2. Amitriptyline and Nortriptyline risk of toxicity (reduce starting dose by 50%)
    3. Citalopram, Escitalopram, Sertraline risk of toxicity (reduce starting dose by 50%)
    4. Omeprazole blood concentrations are 5x higher (increased efficacy)
  3. Ultra-Metabolizers (18% of Swedes and 18% of Ethiopians)
    1. Citalopram, Escitalopram, Sertraline with reduced effect (consider alternative agents)
    2. Omeprazole blood concentrations are 40% lower
  4. Reference
    1. Sim (2006) Clin Pharmacol Ther 79:103-13 [PubMed]
  • Interactions
  • Metabolized by CYP2C19 (Substrates)
  1. Neuropsychiatric drugs
    1. Clomipramine
    2. Imipramine
    3. Hexobarbital
    4. Mephobarbital
    5. Diazepam
    6. Phenobarbital
    7. Phenytoin
  2. Cardiopulmonary Drugs
    1. Propranolol (Inderal)
  3. Antibiotics
    1. Nelfinavir
  4. Miscellaneous
    1. Lansoprazole
    2. Pentamidine
    3. Felbamate
    4. Omeprazole (Prilosec)
  • Interactions
  • Inhibitor of CYP2C19
  1. Neuropsychiatric drugs
    1. Fluvoxamine (Luvox)
  2. Antibiotics
    1. Isoniazid (INH)
    2. Ritonavir
  3. Miscellaneous
    1. Omeprazole (Prilosec)
    2. Cimetidine
  • Interactions
  • Inducer of CYP2C19
  1. Neuropsychiatric Drugs
    1. Carbamazepine
    2. Phenytoin
  2. Antibiotics
    1. Rifampin