Drug interactions
Cisplatin + Phenytoin
Severity: Moderate
Cisplatin 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
Cisplatin-containing chemotherapy has been associated with a fall in serum phenytoin concentrations, which can lead to loss of seizure control. The effect is variable and may be more pronounced during active chemotherapy cycles.
What this interaction means in plain words
Cisplatin 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.
Cisplatin belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
The mechanism is not firmly established; reduced phenytoin absorption and altered clearance have been proposed.
What to do
Monitor total or free phenytoin levels and seizure control during and after cisplatin cycles and adjust the phenytoin dose accordingly. Consider a non-interacting antiseizure drug if levels remain unstable.
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 Cisplatin
- Cidofovir + Cisplatin Contraindicated
- Adefovir + Cisplatin Major
- Adenovirus types 4 and 7 live + Cisplatin Major
- Amikacin + Cisplatin Major
- Amphotericin b deoxycholate + Cisplatin Major
- Amphotericin b + Cisplatin Major
Frequently asked questions
Can I take Cisplatin with Phenytoin?
MediHelp rates the interaction as moderate. Cisplatin 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. Cisplatin-containing chemotherapy has been associated with a fall in serum phenytoin concentrations, which can lead to loss of seizure control. The effect is variable and may be more pronounced during active chemotherapy cycles.
How serious is the interaction between Cisplatin 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: Monitor total or free phenytoin levels and seizure control during and after cisplatin cycles and adjust the phenytoin dose accordingly. Consider a non-interacting antiseizure drug if levels remain unstable.
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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