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Drug Interactions between ivacaftor / lumacaftor and vandetanib

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

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Interactions between your drugs

Moderate

vandetanib lumacaftor

Applies to: vandetanib and ivacaftor / lumacaftor

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may decrease the plasma concentrations of vandetanib, which is a substrate of the isoenzyme. In 16 healthy male subjects, coadministration of rifampin (600 mg/day on days 1 to 31) and vandetanib (single 300 mg oral dose on day 10) resulted in an approximately 40% decrease in vandetanib exposure (AUC) and almost 50% decrease in half-life (from 217.6 hours to 116.3 hours) compared to vandetanib administered alone. There was no significant change in the peak plasma concentration (Cmax) of vandetanib. In the presence of rifampin, the Cmax and AUC of a metabolite, N-desmethylvandetanib, increased by 414% and 266%, respectively. Rifampin also increased the Cmax and AUC of another metabolite, vandetanib N-oxide, by approximately 179% and 126%, respectively. However, the plasma concentrations of vandetanib N-oxide were very low throughout, thus the change in absolute plasma levels induced by rifampin was actually quite small. The clinical implications of these changes are unknown. The two metabolites have shown in vitro pharmacologic activity in cellular assays against vascular endothelial growth factor and epidermal growth factor, with N-desmethylvandetanib exhibiting similar potency to parent drug and vandetanib N-oxide exhibiting less than 1/50 the activity of the parent drug.

MANAGEMENT: Concomitant use of vandetanib with potent CYP450 3A4 inducers should generally be avoided.

References

  1. Martin P, Oliver S, Robertson J, Kennedy SJ, Read J, Duvauchelle T (2011) "Pharmacokinetic drug interactions with vandetanib during cadministration with rifampicin or itraconazole." Drugs R D, 11, p. 37-51
  2. (2011) "Product Information. Vandetanib (vandetanib)." Astra-Zeneca Pharmaceuticals

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Drug and food interactions

Moderate

ivacaftor food

Applies to: ivacaftor / lumacaftor

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of ivacaftor. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Elexacaftor and tezacaftor are also CYP450 3A4 substrates in vitro and may interact similarly with grapefruit juice, whereas lumacaftor is not expected to interact.

ADJUST DOSING INTERVAL: According to prescribing information, systemic exposure to ivacaftor increased approximately 2.5- to 4-fold, systemic exposure to elexacaftor increased approximately 1.9- to 2.5-fold, and systemic exposure to lumacaftor increased approximately 2-fold following administration with fat-containing foods relative to administration in a fasting state. Tezacaftor exposure is not significantly affected by administration of fat-containing foods.

MANAGEMENT: Patients treated with ivacaftor-containing medications should avoid consumption of grapefruit juice and any food that contains grapefruit or Seville oranges. All ivacaftor-containing medications should be administered with fat-containing foods such as eggs, avocados, nuts, meat, butter, peanut butter, cheese pizza, and whole-milk dairy products. A typical cystic fibrosis diet will satisfy this requirement.

References

  1. (2012) "Product Information. Kalydeco (ivacaftor)." Vertex Pharmaceuticals
  2. (2015) "Product Information. Orkambi (ivacaftor-lumacaftor)." Vertex Pharmaceuticals
  3. (2022) "Product Information. Symdeko (ivacaftor-tezacaftor)." Vertex Pharmaceuticals
  4. (2019) "Product Information. Trikafta (elexacaftor/ivacaftor/tezacaftor)." Vertex Pharmaceuticals
View all 4 references

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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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