Drug interactions
Fentanyl + Nafcillin
Severity: Moderate
Fentanyl and Nafcillin: 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
Nafcillin is a CYP3A4 inducer that may lower fentanyl concentrations, risking reduced analgesia or withdrawal. Fentanyl levels may rise again after nafcillin is stopped.
What this interaction means in plain words
Fentanyl and Nafcillin 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
Nafcillin induces CYP3A4, increasing fentanyl metabolism.
What to do
Monitor pain control and withdrawal symptoms during nafcillin therapy and titrate fentanyl as needed. Reduce the dose and watch for sedation when nafcillin ends.
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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Frequently asked questions
Can I take Fentanyl with Nafcillin?
MediHelp rates the interaction as moderate. Fentanyl and Nafcillin 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. Nafcillin is a CYP3A4 inducer that may lower fentanyl concentrations, risking reduced analgesia or withdrawal. Fentanyl levels may rise again after nafcillin is stopped.
How serious is the interaction between Fentanyl and Nafcillin?
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 pain control and withdrawal symptoms during nafcillin therapy and titrate fentanyl as needed. Reduce the dose and watch for sedation when nafcillin ends.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
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