Drug Interactions between elbasvir / grazoprevir and fosphenytoin
This report displays the potential drug interactions for the following 2 drugs:
- elbasvir/grazoprevir
- fosphenytoin
Interactions between your drugs
fosphenytoin elbasvir
Applies to: fosphenytoin and elbasvir / grazoprevir
Consumer information for this interaction is not currently available.
CONTRAINDICATED: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of elbasvir and grazoprevir, both of which are substrates of the isoenzyme. In 10 study subjects, administration of elbasvir 50 mg once daily with efavirenz 600 mg once daily decreased elbasvir peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) by 45%, 54% and 59%, respectively, compared to administration of elbasvir alone. Likewise, when grazoprevir 200 mg once daily and efavirenz 600 mg once daily were given together to 12 study subjects, grazoprevir Cmax, AUC and Cmin decreased by 87%, 83% and 69%, respectively. Efavirenz is generally considered a moderate inducer of CYP450 3A4. More potent inducers such as carbamazepine or phenytoin may interact to an even greater extent.
MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiviral drug levels, concomitant use of elbasvir-grazoprevir with efavirenz or potent CYP450 3A4 inducers is considered contraindicated.
References
- "Product Information. Zepatier (elbasvir-grazoprevir)." Merck & Co., Inc (2016):
fosphenytoin grazoprevir
Applies to: fosphenytoin and elbasvir / grazoprevir
Using grazoprevir together with fosphenytoin is not recommended. Combining these medications may significantly reduce the blood levels of grazoprevir, which may make the medication less effective in treating hepatitis C. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Drug and food interactions
grazoprevir food
Applies to: elbasvir / grazoprevir
Information for this minor interaction is available on the professional version.
Therapeutic duplication warnings
No warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
See also
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
No interaction information available. |
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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