Drug interactions
Phenytoin + Rapacuronium
Severity: Moderate
Phenytoin and Rapacuronium: 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
Chronic phenytoin therapy is known to shorten the effect of nondepolarizing neuromuscular blockers, so rapacuronium may have a reduced or shorter effect. Larger or more frequent doses may be needed during anesthesia.
What this interaction means in plain words
Phenytoin and Rapacuronium 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.
Why it happens
Chronic phenytoin use causes resistance to nondepolarizing blockers, likely through effects at the neuromuscular junction and enhanced clearance.
What to do
Monitor neuromuscular blockade with a nerve stimulator and adjust the dose to effect.
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
Frequently asked questions
Can I take Phenytoin with Rapacuronium?
MediHelp rates the interaction as moderate. Phenytoin and Rapacuronium 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. Chronic phenytoin therapy is known to shorten the effect of nondepolarizing neuromuscular blockers, so rapacuronium may have a reduced or shorter effect. Larger or more frequent doses may be needed during anesthesia.
How serious is the interaction between Phenytoin and Rapacuronium?
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 neuromuscular blockade with a nerve stimulator and adjust the dose to effect.
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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