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Drug Interactions between remdesivir and Xeljanz XR

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

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Interactions between your drugs

Minor

tofacitinib remdesivir

Applies to: Xeljanz XR (tofacitinib) and remdesivir

Coadministration with remdesivir may increase the plasma concentrations of drugs metabolized via CYP450 3A4, but many sources indicate that clinically significant interactions are unlikely. The proposed mechanism is inhibition of CYP450 3A4 by remdesivir. Two drug interaction studies were conducted using the sensitive CYP450 3A4 substrate, midazolam. In the first study, healthy volunteers (n=19) received a single dose of remdesivir (200 mg) and a single dose of midazolam (2.5 mg), which resulted in midazolam's maximum concentration (Cmax) and systemic exposure (AUC) increasing by 29% and 20%, respectively. In the second study, healthy volunteers (n=14) received remdesivir (200 mg once, followed by 100 mg daily) for a total of 10 doses and a single dose of midazolam (2.5 mg) administered with the last dose of remdesivir. Midazolam's Cmax and AUC increased by 45% and 30%, respectively. Both studies indicated that remdesivir is a weak in vivo inhibitor of CYP450 3A4; however, some authorities consider these findings to be clinically insignificant.

References (4)
  1. (2024) "Product Information. Veklury (remdesivir)." Gilead Sciences Pty Ltd, 7.0
  2. (2025) "Product Information. Veklury (remdesivir)." Gilead Sciences
  3. (2024) "Product Information. Veklury (remdesivir)." Gilead Sciences Canada Inc
  4. (2025) "Product Information. Veklury (remdesivir)." Gilead Sciences Ltd

Drug and food interactions

Moderate

tofacitinib food

Applies to: Xeljanz XR (tofacitinib)

MONITOR: Grapefruit juice may increase the plasma concentrations of tofacitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. The extent and clinical significance are unknown. Moreover, pharmacokinetic alterations associated with interactions involving grapefruit juice are often subject to a high degree of interpatient variability.

MANAGEMENT: Until more information is available, some authorities recommend avoiding consumption of grapefruit juice during tofacitinib therapy (Canada). Patients receiving tofacitinib therapy who ingest grapefruits or grapefruit juice should be monitored for adverse effects and undue fluctuations in plasma drug levels.

References (1)
  1. (2024) "Product Information. Xeljanz (tofacitinib)." Pfizer Canada ULC

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.