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Drug Interactions between fostemsavir and pexidartinib

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

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Interactions between your drugs

Minor

pexidartinib fostemsavir

Applies to: pexidartinib and fostemsavir

Coadministration of fostemsavir with moderate or weak CYP450 3A4 inducers may decrease the plasma concentrations of temsavir, the active moiety of fostemsavir. According to the prescribing information, temsavir is a substrate of CYP450 3A4, esterases, P-glycoprotein (P-gp), and breast cancer resistance protein (BCRP). When fostemsavir (600 mg twice daily) was coadministered with the moderate CYP450 3A4 inducer etravirine (200 mg twice daily) in 14 study subjects, mean temsavir peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Ctau) decreased by 48%, 50% and 52%, respectively, compared to fostemsavir administered alone. When the same dosage of fostemsavir was given to 22 study subjects with another moderate CYP450 3A4 inducer, rifabutin (300 mg once daily), mean temsavir Cmax, AUC and Ctau decreased by 27%, 30% and 41%, respectively. These changes are not considered clinically relevant, and no dosage adjustment of fostemsavir is recommended when coadministered with moderate or weak CYP450 3A4 inducers.

References (3)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Cerner Multum, Inc. "Australian Product Information."
  3. (2020) "Product Information. Rukobia (fostemsavir)." ViiV Healthcare

Drug and food interactions

Major

pexidartinib food

Applies to: pexidartinib

ADJUST DOSING INTERVAL: The presence of food may increase the absorption and toxicity of pexidartinib. Administration of pexidartinib with a high-fat meal increased peak plasma concentration (Cmax) and systemic exposure (AUC) by 100% and prolonged the time to reach peak plasma concentration (Tmax) by 2.5 hours.

GENERALLY AVOID: Grapefruit or grapefruit juice may increase the plasma concentration and risk of adverse effects of pexidartinib, including potentially fatal hepatotoxicity. The mechanism is inhibition of CYP450 3A4-mediated metabolism of pexidartinib by certain compounds present in grapefruits. Concomitant administration of itraconazole, a strong CYP450 3A4 inhibitor, increased pexidartinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 48% and 70%, respectively.

MANAGEMENT: Pexidartinib should be administered on an empty stomach, at least one hour before or two hours after a meal or snack. Consumption of grapefruit or grapefruit juice should generally be avoided during pexidartinib therapy. If concomitant use is unavoidable, the dose of pexidartinib should be reduced according to the manufacturer's recommendations. If concomitant use of grapefruit or grapefruit juice is discontinued, the dose of pexidartinib may be increased (after 3 plasma half-lives of a strong CYP450 3A4 inhibitor) to the dose that was used prior to consumption of grapefruit or grapefruit juice.

References (1)
  1. (2019) "Product Information. Turalio (pexidartinib)." Daiichi Sankyo, 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.