Drug interactions
Blinatumomab + Phenytoin
Severity: Moderate
Blinatumomab 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
Blinatumomab causes a transient cytokine release at treatment start that can suppress CYP450 enzymes. Phenytoin has a narrow therapeutic index, so levels may rise and cause toxicity such as ataxia, nystagmus or confusion.
What this interaction means in plain words
Blinatumomab 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.
Blinatumomab belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
Cytokine release from blinatumomab transiently suppresses CYP450 metabolism of phenytoin.
What to do
Monitor phenytoin levels and signs of toxicity, particularly in the first days of the first cycle and early in the second cycle. Adjust the phenytoin dose according to levels.
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 Blinatumomab
- Blinatumomab + Carbamazepine Moderate
- Blinatumomab + Cyclosporin Moderate
- Blinatumomab + Ethosuximide Moderate
- Blinatumomab + Quinidine Moderate
- Blinatumomab + Quinine Moderate
- Blinatumomab + Siponimod Moderate
Frequently asked questions
Can I take Blinatumomab with Phenytoin?
MediHelp rates the interaction as moderate. Blinatumomab 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. Blinatumomab causes a transient cytokine release at treatment start that can suppress CYP450 enzymes. Phenytoin has a narrow therapeutic index, so levels may rise and cause toxicity such as ataxia, nystagmus or confusion.
How serious is the interaction between Blinatumomab 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 phenytoin levels and signs of toxicity, particularly in the first days of the first cycle and early in the second cycle. Adjust the phenytoin dose according to levels.
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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