Drug Interaction Report

GENERALLY AVOID: Coadministration with erdafitinib may increase the plasma concentrations of drugs that are substrates of organic cation transporter 2 (OCT2), resulting in increased toxicity of these drugs. In vitro, erdafitinib has been shown to be an inhibitor of OCT2. However, no pharmacokinetic data are available from drug interaction studies.

MANAGEMENT: Concomitant use of erdafitinib and OCT2 substrates should generally be avoided or the dose of the OCT2 substrates should be reduced based on tolerability.

In vitro data suggest that grapefruit juice may inhibit the CYP450 3A4 first-pass metabolism of dofetilide. Decreased first-pass metabolism may increase dofetilide concentrations and increase the risk of QT interval prolongation and arrhythmias. The clinical significance is unknown, since dofetilide has a high oral bioavailability and a low affinity for CYP450 3A4. The manufacturer recommends caution.