Drug interactions
Belumosudil + Phenytoin
Severity: Moderate
Belumosudil and Phenytoin: 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
Phenytoin is a strong CYP3A4 inducer, and belumosudil is cleared by CYP3A4. Exposure to belumosudil falls, which may reduce its efficacy in chronic graft-versus-host disease.
What this interaction means in plain words
Belumosudil and Phenytoin 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.
Belumosudil belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, increasing belumosudil metabolism.
What to do
Increase belumosudil to 200 mg twice daily during co-administration, as recommended in labeling. Assess clinical response to the combination.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Belumosudil
- Amobarbital + Belumosudil Moderate
- Apalutamide + Belumosudil Moderate
- Armodafinil + Belumosudil Moderate
- Belumosudil + Bosentan Moderate
- Belumosudil + Carbamazepine Moderate
- Belumosudil + Dexlansoprazole Moderate
Frequently asked questions
Can I take Belumosudil with Phenytoin?
MediHelp rates the interaction as moderate. Belumosudil and Phenytoin 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. Phenytoin is a strong CYP3A4 inducer, and belumosudil is cleared by CYP3A4. Exposure to belumosudil falls, which may reduce its efficacy in chronic graft-versus-host disease.
How serious is the interaction between Belumosudil and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Increase belumosudil to 200 mg twice daily during co-administration, as recommended in labeling. Assess clinical response to the combination.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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