Drug interactions
Phenytoin + Treosulfan
Severity: Moderate
Phenytoin and Treosulfan: 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
Treosulfan conditioning regimens carry a risk of seizures, and phenytoin is often given as prophylaxis. Phenytoin levels may be altered, with possible loss of seizure protection or toxicity.
What this interaction means in plain words
Phenytoin and Treosulfan 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 belongs to Central Nervous System; Treosulfan belongs to Oncology.
Why it happens
Mechanism is not firmly established; reduced oral absorption from mucositis or vomiting and altered metabolism have been proposed.
What to do
Monitor phenytoin concentrations frequently, preferably using the intravenous route if oral absorption is unreliable. Adjust the dose accordingly.
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 Treosulfan
- Treosulfan + Vitamin e Minor
Frequently asked questions
Can I take Phenytoin with Treosulfan?
MediHelp rates the interaction as moderate. Phenytoin and Treosulfan 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. Treosulfan conditioning regimens carry a risk of seizures, and phenytoin is often given as prophylaxis. Phenytoin levels may be altered, with possible loss of seizure protection or toxicity.
How serious is the interaction between Phenytoin and Treosulfan?
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 phenytoin concentrations frequently, preferably using the intravenous route if oral absorption is unreliable. Adjust the dose accordingly.
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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