Drug interactions
Lomustine + Phenytoin
Severity: Moderate
Lomustine 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
Enzyme-inducing phenytoin may lower exposure to lomustine's active metabolites and reduce antitumor effect. Cytotoxic chemotherapy can also alter phenytoin concentrations, so seizure control may change.
What this interaction means in plain words
Lomustine 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.
Lomustine belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces hepatic enzymes that increase lomustine clearance; chemotherapy effects on phenytoin absorption or metabolism are variable.
What to do
Consider a non-enzyme-inducing antiseizure drug for patients receiving lomustine. If phenytoin is continued, monitor its levels and the tumor response.
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 Lomustine
- Adenovirus types 4 and 7 live + Lomustine Contraindicated
- Bcg vaccine live + Lomustine Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Lomustine Contraindicated
- Lomustine + Measles mumps and rubella vaccine Contraindicated
- Lomustine + Measles mumps and rubella vaccine live Contraindicated
- Lomustine + Measles mumps rubella and varicella vaccine live Contraindicated
Frequently asked questions
Can I take Lomustine with Phenytoin?
MediHelp rates the interaction as moderate. Lomustine 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. Enzyme-inducing phenytoin may lower exposure to lomustine's active metabolites and reduce antitumor effect. Cytotoxic chemotherapy can also alter phenytoin concentrations, so seizure control may change.
How serious is the interaction between Lomustine 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: Consider a non-enzyme-inducing antiseizure drug for patients receiving lomustine. If phenytoin is continued, monitor its levels and the tumor response.
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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