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Drug Interactions between efavirenz and Olysio

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

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Interactions between your drugs

Major

efavirenz simeprevir

Applies to: efavirenz and Olysio (simeprevir)

GENERALLY AVOID: Coadministration with potent and some moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of simeprevir, which is primarily metabolized by the isoenzyme. In 18 healthy study subjects administered simeprevir (200 mg once daily) in combination with the potent CYP450 3A4 inducer rifampin (600 mg once daily) for 7 days, mean simeprevir peak plasma concentration (Cmax) increased by 31% but systemic exposure (AUC) and trough plasma concentration (Cmin) decreased by 48% and 92%, respectively. Likewise, when simeprevir (150 mg once daily) was given with the moderate inducer efavirenz (600 mg once daily) to 23 healthy subjects for 14 days, mean simeprevir Cmax, AUC and Cmin decreased by 51%, 71% and 91%, respectively. Simeprevir had no significant effects on the pharmacokinetics of efavirenz or rifampin, but increased the AUC of metabolite 25-desacetyl-rifampin by 24%.

MANAGEMENT: The use of simeprevir in combination with potent and some moderate CYP450 3A4 inducers such as carbamazepine, dexamethasone, efavirenz, enzalutamide, eslicarbazepine, etravirine, nevirapine, oxcarbazepine, phenobarbital, phenytoin, primidone, rifamycins, St. John's wort, and tipranavir should generally be avoided.

References (2)
  1. (2001) "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals
  2. (2013) "Product Information. Olysio (simeprevir)." Janssen Pharmaceuticals

Drug and food interactions

Moderate

efavirenz food

Applies to: efavirenz

ADJUST DOSING INTERVAL: Administration with food increases the plasma concentrations of efavirenz and may increase the frequency of adverse reactions. According to the product labeling, administration of efavirenz capsules (600 mg single dose) with a high-fat/high-caloric meal (894 kcal, 54 g fat, 54% calories from fat) or a reduced-fat/normal-caloric meal (440 kcal, 2 g fat, 4% calories from fat) was associated with mean increases of 39% and 51% in efavirenz peak plasma concentration (Cmax) and 22% and 17% in systemic exposure (AUC), respectively, compared to administration under fasted conditions. For efavirenz tablets, administration of a single 600 mg dose with a high-fat/high-caloric meal (approximately 1000 kcal, 500-600 kcal from fat) resulted in a 79% increase in mean Cmax and a 28% increase in mean AUC of efavirenz relative to administration under fasted conditions.

GENERALLY AVOID: Alcohol may potentiate the central nervous system (CNS) depressant effects of efavirenz. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

MANAGEMENT: Efavirenz should be taken on an empty stomach, preferably at bedtime. Dosing at bedtime may improve the tolerability of nervous system symptoms such as dizziness, insomnia, impaired concentration, somnolence, abnormal dreams and hallucinations, although they often resolve on their own after the first 2 to 4 weeks of therapy . Patients should be advised of the potential for additive central nervous system effects when efavirenz is used concomitantly with alcohol or psychoactive drugs, and to avoid driving or operating hazardous machinery until they know how the medication affects them.

References (4)
  1. (2001) "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals
  2. (2023) "Product Information. Sustiva (efavirenz)." Bristol-Myers Squibb, SUPPL-59/47
  3. (2024) "Product Information. Stocrin (efavirenz)." Merck Sharp & Dohme (Australia) Pty Ltd
  4. (2024) "Product Information. Efavirenz (efavirenz)." Viatris UK Healthcare Ltd
Moderate

simeprevir food

Applies to: Olysio (simeprevir)

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of simeprevir, although the type of food does not seem to matter. In healthy study subjects, administration of simeprevir after a high-fat, high-caloric (928 kcal) breakfast increased systemic exposure (AUC) by 61% and delayed absorption by 1 hour, while administration after a normal caloric (533 kcal) breakfast increased AUC by 69% and delayed absorption by 1.5 hours.

MANAGEMENT: To ensure maximal oral absorption, simeprevir should be administered with food.

References (1)
  1. (2013) "Product Information. Olysio (simeprevir)." Janssen Pharmaceuticals

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

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