Drug interactions
Phenytoin + Sufentanil
Severity: Moderate
Phenytoin and Sufentanil: 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
Phenytoin induces CYP3A4 and may speed the breakdown of sufentanil, lowering its concentrations and shortening or weakening analgesia. Stopping phenytoin later can allow sufentanil levels to rise again, increasing the risk of opioid effects.
What this interaction means in plain words
Phenytoin and Sufentanil 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; Sufentanil belongs to Musculoskeletal.
Why it happens
Phenytoin induces hepatic and intestinal CYP3A4, increasing sufentanil clearance.
What to do
Monitor analgesic response and titrate sufentanil to effect, anticipating higher requirements. Watch for sedation and respiratory depression if phenytoin is stopped or the dose is reduced.
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 Sufentanil
- Alprazolam + Sufentanil Major
- Amitriptyline + Sufentanil Major
- Amobarbital + Sufentanil Major
- Aripiprazole + Sufentanil Major
- Asenapine + Sufentanil Major
- Baclofen + Sufentanil Major
Frequently asked questions
Can I take Phenytoin with Sufentanil?
MediHelp rates the interaction as moderate. Phenytoin and Sufentanil 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 induces CYP3A4 and may speed the breakdown of sufentanil, lowering its concentrations and shortening or weakening analgesia. Stopping phenytoin later can allow sufentanil levels to rise again, increasing the risk of opioid effects.
How serious is the interaction between Phenytoin and Sufentanil?
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 analgesic response and titrate sufentanil to effect, anticipating higher requirements. Watch for sedation and respiratory depression if phenytoin is stopped or the dose is reduced.
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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