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Drug Interactions between crizotinib and nirmatrelvir / ritonavir

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

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Interactions between your drugs

Major

ritonavir crizotinib

Applies to: nirmatrelvir / ritonavir and crizotinib

GENERALLY AVOID: Coadministration with potent inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of crizotinib, which is primarily metabolized by the isoenzyme. In study subjects, administration of a single 150 mg oral dose of crizotinib during treatment with the potent CYP450 3A4 inhibitor ketoconazole (200 mg twice daily) resulted in an approximately 1.4-fold increase in crizotinib peak plasma concentration (Cmax) and 3.2-fold increase in systemic exposure (AUC) compared to crizotinib administered alone. The effect of CYP450 3A4 inhibitors on steady-state crizotinib exposure has not been evaluated. Because crizotinib is associated with concentration-dependent prolongation of the QT interval, increased levels may potentiate the risk of ventricular arrhythmias such as torsade de pointes and sudden death.

MANAGEMENT: Concomitant use of crizotinib with potent CYP450 3A4 inhibitors should generally be avoided. Some authorities recommend avoiding concomitant use of crizotinib during and for 2 weeks after treatment with itraconazole.

References (3)
  1. (2002) "Product Information. Sporanox (itraconazole)." Janssen Pharmaceuticals
  2. Cerner Multum, Inc. "Australian Product Information."
  3. (2011) "Product Information. Xalkori (crizotinib)." Pfizer U.S. Pharmaceuticals Group

Drug and food interactions

Major

crizotinib food

Applies to: crizotinib

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of crizotinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. Because crizotinib is associated with concentration-dependent prolongation of the QT interval, increased levels may potentiate the risk of ventricular arrhythmias such as torsade de pointes and sudden death.

Food has no significant effect on the gastrointestinal absorption of crizotinib. According to the product labeling, a high-fat meal reduced crizotinib peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 14%.

MANAGEMENT: Patients treated with crizotinib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. Crizotinib may be taken without regards to food.

References (1)
  1. (2011) "Product Information. Xalkori (crizotinib)." Pfizer U.S. Pharmaceuticals Group
Moderate

ritonavir food

Applies to: nirmatrelvir / ritonavir

ADJUST DOSING INTERVAL: Administration with food may modestly affect the bioavailability of ritonavir from the various available formulations. When the oral solution was given under nonfasting conditions, peak ritonavir concentrations decreased 23% and the extent of absorption decreased 7% relative to fasting conditions. Dilution of the oral solution (within one hour of dosing) with 240 mL of chocolate milk or a nutritional supplement (Advera or Ensure) did not significantly affect the extent and rate of ritonavir absorption. When a single 100 mg dose of the tablet was administered with a high-fat meal (907 kcal; 52% fat, 15% protein, 33% carbohydrates), approximately 20% decreases in mean peak concentration (Cmax) and systemic exposure (AUC) were observed relative to administration after fasting. Similar decreases in Cmax and AUC were reported when the tablet was administered with a moderate-fat meal. In contrast, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate) relative to fasting.

MANAGEMENT: Ritonavir should be taken with meals to enhance gastrointestinal tolerability.

References (1)
  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical

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.