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Drug Interactions between Grisactin 500 and Kalydeco

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

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Interactions between your drugs

Moderate

griseofulvin ivacaftor

Applies to: Grisactin 500 (griseofulvin) and Kalydeco (ivacaftor)

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of ivacaftor, which is primarily metabolized by the isoenzyme. In study subjects, administration of a single 150 mg dose of ivacaftor with the potent CYP450 3A4 inducer rifampin (600 mg once daily) decreased ivacaftor peak plasma concentration (Cmax) and systemic exposure (AUC) by 80% and 89%, respectively, compared to administration of ivacaftor alone. When lumacaftor/ivacaftor was coadministered with rifampin, lumacaftor pharmacokinetics were minimally affected, but ivacaftor Cmax and AUC decreased by an average of 50% and 57%, respectively. No pharmacokinetic data are available for elexacaftor or tezacaftor, but decreased exposures are expected according to prescribing information.

MANAGEMENT: The potential for diminished pharmacologic effects of ivacaftor-containing medications should be considered during coadministration with CYP450 3A4 inducers. Alternative treatments may be required if an interaction is suspected.

References

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

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Drug and food interactions

Moderate

griseofulvin food

Applies to: Grisactin 500 (griseofulvin)

MONITOR: Isolated case reports have suggested that the ingestion of alcohol during griseofulvin therapy may rarely cause disulfiram-like reactions, flushing, tachycardia, or increased effects of alcohol. The mechanism is unknown.

MANAGEMENT: Patients should be advised of the possibility of increased adverse effects or a disulfiram-like reaction.

References

  1. "Product Information. Grifulvin V (griseofulvin)." Ortho McNeil Pharmaceutical
  2. "Product Information. Fulvicin P/G (griseofulvin)." Schering Corporation PROD (2002):
  3. Cerner Multum, Inc. "Australian Product Information." O 0

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Moderate

ivacaftor food

Applies to: Kalydeco (ivacaftor)

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

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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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