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Drug Interactions between elbasvir / grazoprevir and felbamate

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

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Interactions between your drugs

Moderate

felbamate elbasvir

Applies to: felbamate and elbasvir / grazoprevir

MONITOR: Coadministration with inducers of CYP450 3A4 may 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. The extent to which other, less potent inducers of CYP450 3A4 may interact with elbasvir and grazoprevir is unknown.

MANAGEMENT: The potential for diminished pharmacologic effects of elbasvir-grazoprevir should be considered during coadministration with CYP450 3A4 inducers. Alternative treatments may be required if an interaction is suspected.

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

felbamate grazoprevir

Applies to: felbamate and elbasvir / grazoprevir

MONITOR: Coadministration with inducers of CYP450 3A4 may 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. The extent to which other, less potent inducers of CYP450 3A4 may interact with elbasvir and grazoprevir is unknown.

MANAGEMENT: The potential for diminished pharmacologic effects of elbasvir-grazoprevir should be considered during coadministration with CYP450 3A4 inducers. Alternative treatments may be required if an interaction is suspected.

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

Drug and food interactions

Moderate

felbamate food

Applies to: felbamate

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References (4)
  1. Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
  3. (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
  4. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
Minor

grazoprevir food

Applies to: elbasvir / grazoprevir

Food does not appear to have clinically significant effects on the pharmacokinetics of elbasvir and grazoprevir. When a single 50 mg-100 mg dose of elbasvir-grazoprevir was administered to healthy study subjects with a high-fat meal (900 kcal; 500 kcal from fat), elbasvir peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 15% and 11%, respectively, while grazoprevir Cmax and AUC increased by 2.8- and 1.5-fold, respectively, compared to administration under fasting conditions. According to the product labeling, elbasvir-grazoprevir may be administered with or without food.

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

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.