Drug interactions
Fentanyl + Quinidine
Severity: Moderate
Fentanyl and Quinidine: 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
Quinidine mainly inhibits CYP2D6 and only weakly inhibits CYP3A4, so its effect on fentanyl metabolism is probably modest. Raised fentanyl levels could still increase sedation and respiratory depression, and quinidine also prolongs the QT interval.
What this interaction means in plain words
Fentanyl and Quinidine 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.
Fentanyl belongs to Musculoskeletal; Quinidine belongs to Anti Parasitic.
Why it happens
Possible weak CYP3A4 inhibition reducing fentanyl clearance.
What to do
Monitor for sedation and respiratory depression when quinidine is added to fentanyl. Reduce the fentanyl dose if needed and check the ECG when QT risk factors exist.
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
Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Frequently asked questions
Can I take Fentanyl with Quinidine?
MediHelp rates the interaction as moderate. Fentanyl and Quinidine 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. Quinidine mainly inhibits CYP2D6 and only weakly inhibits CYP3A4, so its effect on fentanyl metabolism is probably modest. Raised fentanyl levels could still increase sedation and respiratory depression, and quinidine also prolongs the QT interval.
How serious is the interaction between Fentanyl and Quinidine?
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 for sedation and respiratory depression when quinidine is added to fentanyl. Reduce the fentanyl dose if needed and check the ECG when QT risk factors exist.
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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