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Drug Interactions between istradefylline and voriconazole

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

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Interactions between your drugs

Major

voriconazole istradefylline

Applies to: voriconazole and istradefylline

ADJUST DOSE: Coadministration with potent inhibitors of CYP450 3A4 may significantly increase the plasma concentrations and risk of adverse effects of istradefylline, which is primarily metabolized by CYP450 3A4 and 1A1. In study subjects, administration of a single 40 mg dose of istradefylline with the potent CYP450 3A4 inhibitor ketoconazole (200 mg twice daily for 4 days) increased the total systemic exposure (AUC(inf)) of istradefylline by 2.5-fold.

MANAGEMENT: The manufacturer suggests that the maximum dose of istradefylline when coadministered with potent CYP450 3A4 inhibitors be reduced to 20 mg once daily. Patients should be monitored for adverse effects including dyskinesia, impulse control issues, dizziness, constipation, nausea, hallucinations, and insomnia.

References (1)
  1. (2019) "Product Information. Nourianz (istradefylline)." Kyowa Kirin, Inc

Drug and food interactions

Moderate

voriconazole food

Applies to: voriconazole

ADJUST DOSING INTERVAL: Food reduces the oral absorption and bioavailability of voriconazole. According to the product labeling, administration of multiple doses of voriconazole with high-fat meals decreased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by 34% and 24%, respectively, when the drug is administered as a tablet, and by 58% and 37%, respectively, when administered as the oral suspension.

MANAGEMENT: To ensure maximal oral absorption, voriconazole tablets and oral suspension should be taken at least one hour before or after a meal.

References (2)
  1. (2002) "Product Information. VFEND (voriconazole)." Pfizer U.S. Pharmaceuticals
  2. Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT (2009) "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm, 66, p. 1438-67
Moderate

istradefylline food

Applies to: istradefylline

ADJUST DOSE: Smoking tobacco may decrease the steady-state systemic exposure of istradefylline by 38% to 54%.

MANAGEMENT: The possibility of reduced therapeutic effects of istradefylline should be considered in smokers. The manufacturer recommends an istradefylline dosage of 40 mg once daily in patients who smoke 20 or more cigarettes (or the equivalent amount of another tobacco product) per day.

References (1)
  1. (2019) "Product Information. Nourianz (istradefylline)." Kyowa Kirin, 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.

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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