Drug interactions
Phenytoin + Sufentanil sl
Severity: Major
Phenytoin and Sufentanil sl: major 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 may lower sufentanil concentrations, which can reduce pain relief and precipitate withdrawal in dependent patients. Stopping phenytoin may cause sufentanil levels to rise, with a risk of respiratory depression.
What this interaction means in plain words
Phenytoin and Sufentanil sl can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
CYP3A4 induction by phenytoin increases the metabolism of sufentanil.
What to do
Monitor analgesia and withdrawal signs while on both drugs. After phenytoin is stopped, monitor for sedation and respiratory depression and lower the sufentanil dose if needed.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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 Sufentanil sl?
MediHelp rates the interaction as major. Phenytoin and Sufentanil sl can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenytoin may lower sufentanil concentrations, which can reduce pain relief and precipitate withdrawal in dependent patients. Stopping phenytoin may cause sufentanil levels to rise, with a risk of respiratory depression.
How serious is the interaction between Phenytoin and Sufentanil sl?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor analgesia and withdrawal signs while on both drugs. After phenytoin is stopped, monitor for sedation and respiratory depression and lower the sufentanil dose if needed.
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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