Fosamprenavir and Larotrectinib interaction
Fosamprenavir and Larotrectinib: the Larotrectinib prescribing label flags this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Larotrectinib (VITRAKVI) label · effective 2026-05-22
Strong CYP3A4 Inhibitors: Avoid coadministration of strong CYP3A4 inhibitors with VITRAKVI.
Avoid coadministration of VITRAKVI with strong CYP3A4 inhibitors, including grapefruit or grapefruit juice.
If coadministration of strong CYP3A4 inhibitors cannot be avoided, modify VITRAKVI dose as recommended [see Dosage and Administration (2.5) ] .
Moderate CYP3A4 Inhibitors: Monitor for adverse reactions more frequently in patients coadministered a moderate CYP3A4 inhibitor with VITRAKVI and reduce the VITRAKVI dosage based on severity of adverse reactions.
Effects of Other Drugs on VITRAKVI Strong and Moderate CYP3A4 Inhibitors Coadministration of VITRAKVI with a strong or moderate CYP3A4 inhibitor may increase larotrectinib plasma concentrations, which may result in a higher incidence of adverse reactions [see Clinical Pharmacology (12.3) ].
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.