II. Precautions: CYP2C9 Deficiency related to Warfarin toxicity

  1. Higher risk for Warfarin toxicity and bleeding complications
  2. Start with lower doses
  3. Reaching a steady-state INR on Warfarin requires >3 months
  4. Voora (2005) Thromb Haemost 93:700-5 [PubMed]

III. Interactions: Metabolized by CYP2C9 (Substrates)

  1. Cardiopulmonary Drugs
    1. Carvedilol (Coreg)
    2. Tolbutamide
    3. Angiotensin Receptor Blockers (ARBs) affected
      1. Losartan (Cozaar)
      2. Irbesartan (Avapro)
    4. ARBs not affected by Cytochrome P450 System
      1. Valsartan
      2. Eprosartan
      3. Candesartan
  2. Miscellaneous
    1. Diclofenac
    2. Ibuprofen
    3. Piroxicam
    4. Celecoxib (Celebrex)
    5. Warfarin
    6. Glipizide

IV. Interactions: Inhibitor of CYP2C9

  1. Neuropsychiatric drugs
    1. Fluoxetine (Prozac)
  2. Cardiopulmonary Drugs
    1. Amiodarone
    2. Zafirlukast (Accolate)
    3. Fluvastatin (Lescol)
  3. Antibiotics and Antifungals
    1. Fluconazole (Diflucan)
    2. Ketoconazole
    3. Metronidazole (Flagyl)
    4. Ritonavir
    5. Trimethoprim-sulfamethoxazole (Septra)

V. Interactions: Inducer of CYP2C9

  1. Neuropsychiatric drugs
    1. Carbamazepine
    2. Phenobarbital
    3. Phenytoin
  2. Antibiotics
    1. Rifampin

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Ontology: CYP2C9 protein, human (C0608437)

Definition (NCI) Cytochrome P450 2C9 (490 aa, ~56 kDa) is encoded by the human CYP2C9 gene. This protein is involved in the oxidation of fatty acids, steroids and xenobiotics.
Concepts Amino Acid, Peptide, or Protein (T116) , Enzyme (T126)
MSH C450260
English cyp2c9, Cytochrome P450 MP-4, Cytochrome P450 PB-1, (R)-Limonene 6-Monooxygenase, EC 1.14.13.48, Cytochrome P450 MP-8, EC 1.14.13.80, (S)-Limonene 7-Monooxygenase, Cytochrome P-450MP, EC 1.14.13.-, EC 1.14.13.49, S-mephenytoin 4-hydroxylase, human, cytochrome P-450 CYP2C10 (human), cytochrome P-450 CYP2C9, human, warfarin-7-hydroxylase, human, cytochrome P-450 CYP2C9 (human), CYP2C9 protein, human, Flavoprotein-Linked Monooxygenase, CYP2C9, P-450MP, P450 MP-4, P450 PB-1, Cytochrome P450 2C9, Cytochrome P450, Family 2, Subfamily C, Polypeptide 9, Cytochrome P450, Subfamily IIC (Mephenytoin 4-Hydroxylase), Polypeptide 10, Cytochrome P450, Subfamily IIC (Mephenytoin 4-Hydroxylase), Polypeptide 9, Mephenytoin 4-Hydroxylase, Microsomal Monooxygenase, S-Mephenytoin 4-Hydroxylase, Xenobiotic Monooxygenase, CYPIIC9, CYP2C10 protein, human, P-450MP protein, human, P450 MP-4 protein, human, P450 MP-8 protein, human