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Drug Interactions between clarithromycin and istradefylline

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

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Interactions between your drugs

Major

clarithromycin istradefylline

Applies to: clarithromycin 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

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
Minor

clarithromycin food

Applies to: clarithromycin

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.

References (1)
  1. Cheng KL, Nafziger AN, Peloquin CA, Amsden GW (1998) "Effect of grapefruit juice on clarithromycin pharmacokinetics." Antimicrob Agents Chemother, 42, p. 927-9

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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