Elbasvir / Grazoprevir

Phenytoin

Contraindicated.

Available pharmaceutical opinion

Document made available to the pharmacist to communicate a drug interaction to the doctor.

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Mechanism

Phenytoin can induce the metabolism (CYP 3A4) and decrease the plasma concentration of Elbasvir / Grazoprevir.

Elbasvir / Grazoprevir

Pharmacodynamic effects

Possible decrease of clinical efficacy.

Recommendations

Do not administer with potent CYP3A4 inducers.

Alternative solution(s)

Phenytoin

Pharmacodynamic effects

Recommendations

Alternative solution(s)

Monitor

Tests

Pharmacokinetic parameters

Comment

Ref #3222 : This association has not been studied but the product monograph contraindicated concomitant use of elbasvir/grazoprevir with potent CYP3A4 inducers. Coadministration of efavirenz, a moderate CYP3A4 inducer, with elbasvir/grazoprevir resulted in a reduction of more than 80% of grazoprevir exposures.

Reference
  • 3222
    Elbasvir/Grazoprevir (Zepatier), Merck, Québec, Canada, 28 juin 2017.