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Drug Interactions between elbasvir / grazoprevir and Priftin

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

rifapentine elbasvir

Applies to: Priftin (rifapentine) 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

  1. "Product Information. Zepatier (elbasvir-grazoprevir)." Merck & Co., Inc (2016):
Major

rifapentine grazoprevir

Applies to: Priftin (rifapentine) and elbasvir / grazoprevir

Using grazoprevir together with rifapentine 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.

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Drug and food interactions

Moderate

rifapentine food

Applies to: Priftin (rifapentine)

Consumer information for this interaction is not currently available.

ADJUST DOSING INTERVAL: Administration with food may increase the oral bioavailability of rifapentine and reduce the incidence of gastrointestinal adverse events. Administration with a high fat meal typically increases rifapentine's maximum concentration (Cmax) and systemic exposure (AUC) by approximately 40% to 50% over that observed when rifapentine is administered under fasting conditions. Rifapentine is often prescribed in combination with isoniazid. When single doses of rifapentine (900 mg) and isoniazid (900 mg) were administered with a low fat, high carbohydrate breakfast, the Cmax and AUC of rifapentine increased by 47% and 51%, respectively. On the other hand, isoniazid's Cmax and AUC decreased by 46% and 23%, respectively.

MANAGEMENT: Products containing oral rifapentine as the sole ingredient recommend administration with a meal to increase bioavailability and reduce the occurrence of gastrointestinal upset, nausea, and/or vomiting. Consultation of product labeling for combination products and/or relevant guidelines may be helpful if rifapentine is combined with a medication that is typically taken on an empty stomach.

References

  1. "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India) 2 (2021):
  2. "Product Information. Priftin (rifapentine)." sanofi-aventis (2021):
Minor

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.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor 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.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.