Drug interactions
Fentanyl + Haloperidol
Severity: Moderate
Fentanyl and Haloperidol: 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
Haloperidol adds to the sedative and hypotensive effects of fentanyl and may increase respiratory depression. Both drugs can also prolong the QT interval, and haloperidol is a weak CYP3A4 substrate and inhibitor with limited effect on fentanyl levels.
What this interaction means in plain words
Fentanyl and Haloperidol 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; Haloperidol belongs to Central Nervous System.
Why it happens
Additive CNS depression and possible additive QT effects, with minor CYP3A4-related pharmacokinetic effects.
What to do
Monitor sedation, blood pressure and respiratory rate, and consider an ECG in patients with QT risk factors. Reduce doses if excessive sedation occurs.
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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Fentanyl with Haloperidol?
MediHelp rates the interaction as moderate. Fentanyl and Haloperidol 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. Haloperidol adds to the sedative and hypotensive effects of fentanyl and may increase respiratory depression. Both drugs can also prolong the QT interval, and haloperidol is a weak CYP3A4 substrate and inhibitor with limited effect on fentanyl levels.
How serious is the interaction between Fentanyl and Haloperidol?
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 sedation, blood pressure and respiratory rate, and consider an ECG in patients with QT risk factors. Reduce doses if excessive sedation occurs.
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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