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Drug Interactions between lapatinib and tovorafenib

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

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Interactions between your drugs

Moderate

lapatinib tovorafenib

Applies to: lapatinib and tovorafenib

MONITOR: Coadministration with inhibitors of CYP450 2C8 may increase the plasma concentrations and effects of tovorafenib, which has been found in vitro to be primarily metabolized by CYP450 2C8 and aldehyde oxidase, and to a lesser extent, by the isoenzymes CYP450 3A, 2C9, and 2C19. Increased plasma concentrations may increase the risk for adverse drug reactions including but not limited to, hemorrhage, skin toxicity, photosensitivity, hepatotoxicity, and reduced growth velocity in patients 18 years of age or younger. However, data from formal clinical drug interaction studies are not available.

MANAGEMENT: Caution is advised if tovorafenib is prescribed in combination with CYP450 2C8 inhibitors. Patients should be monitored for the development of hemorrhage, skin toxicity, photosensitivity, hepatotoxicity, and, in patients 18 years of age or younger, reduced growth velocity. Alternative therapy may need to be considered if a drug interaction is suspected.

References (1)
  1. (2024) "Product Information. Ojemda (tovorafenib)." Day One Biopharmaceuticals, Inc.

Drug and food interactions

Moderate

lapatinib food

Applies to: lapatinib

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of lapatinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits.

ADJUST DOSING INTERVAL: Food can significantly increase the oral bioavailability of lapatinib. According to the manufacturer, lapatinib peak plasma concentration (Cmax) was approximately 2.5- and 3-fold higher and systemic exposure (AUC) 3- and 4-fold higher when administered with a low fat meal (5% fat; 500 calories) or with a high-fat meal (50% fat; 1000 calories), respectively, compared to fasting. Dividing the daily dose also resulted in an approximately 2-fold higher systemic exposure at steady state compared to the same total dose administered once daily.

MANAGEMENT: Patients treated with lapatinib should preferably avoid the consumption of grapefruit or grapefruit juice. The manufacturer recommends that lapatinib be administered at least one hour before or one hour after a meal. The lapatinib dose is administered once daily and should not be divided.

References (1)
  1. (2007) "Product Information. Tykerb (lapatinib)." Novartis 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.

See also

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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.

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