Drug interactions
Fosphenytoin + Pazopanib
Severity: Moderate
Fosphenytoin and Pazopanib: 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
Fosphenytoin is converted to phenytoin, a recognized inducer of CYP3A4. Induction can lower pazopanib plasma concentrations and may reduce antitumor efficacy.
What this interaction means in plain words
Fosphenytoin and Pazopanib 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.
Fosphenytoin belongs to Central Nervous System; Pazopanib belongs to Oncology.
Why it happens
Phenytoin induces CYP3A4, increasing the metabolic clearance of pazopanib.
What to do
Avoid strong CYP3A4 inducers when possible and consider a non-enzyme-inducing anticonvulsant. If coadministration is unavoidable, monitor tumor response and pazopanib tolerability closely.
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 Pazopanib
- Adagrasib + Pazopanib Major
- Amiodarone + Pazopanib Major
- Amisulpride + Pazopanib Major
- Amobarbital + Pazopanib Major
- Anagrelide + Pazopanib Major
- Apalutamide + Pazopanib Major
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Fosphenytoin with Pazopanib?
MediHelp rates the interaction as moderate. Fosphenytoin and Pazopanib 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. Fosphenytoin is converted to phenytoin, a recognized inducer of CYP3A4. Induction can lower pazopanib plasma concentrations and may reduce antitumor efficacy.
How serious is the interaction between Fosphenytoin and Pazopanib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid strong CYP3A4 inducers when possible and consider a non-enzyme-inducing anticonvulsant. If coadministration is unavoidable, monitor tumor response and pazopanib tolerability closely.
What other medicines interact with Pazopanib?
MediHelp also lists interactions of Pazopanib with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pazopanib page.
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