Drug interactions
Fostamatinib + Posaconazole
Severity: Moderate
Fostamatinib and Posaconazole: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Posaconazole increases exposure to R406, the active metabolite of fostamatinib, which can increase dose-related toxicities such as hypertension, diarrhea, neutropenia and hepatotoxicity. Fostamatinib may also modestly raise concentrations of P-gp substrates such as posaconazole.
What this interaction means in plain words
Fostamatinib and Posaconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fostamatinib belongs to Oncology; Posaconazole belongs to Anti Fungals.
Why it happens
Posaconazole inhibits CYP3A4 metabolism of R406, and fostamatinib may inhibit P-gp efflux of posaconazole.
What to do
Monitor blood pressure, liver enzymes and blood counts, and reduce the fostamatinib dose if toxicities arise. Watch for posaconazole adverse effects.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Fostamatinib
- Colchicine + Fostamatinib Major
- Fostamatinib + Phenytoin Major
- Amobarbital + Fostamatinib Moderate
- Apalutamide + Fostamatinib Moderate
- Atorvastatin + Fostamatinib Moderate
- Bosentan + Fostamatinib Moderate
Frequently asked questions
Can I take Fostamatinib with Posaconazole?
MediHelp rates the interaction as moderate. Fostamatinib and Posaconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Posaconazole increases exposure to R406, the active metabolite of fostamatinib, which can increase dose-related toxicities such as hypertension, diarrhea, neutropenia and hepatotoxicity. Fostamatinib may also modestly raise concentrations of P-gp substrates such as posaconazole.
How serious is the interaction between Fostamatinib and Posaconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, liver enzymes and blood counts, and reduce the fostamatinib dose if toxicities arise. Watch for posaconazole adverse effects.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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