Drug interactions
Fentanyl + Isoflurane
Severity: Moderate
Fentanyl and Isoflurane: 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
Fentanyl is commonly used with inhalational anesthetics, and together they deepen anesthesia and reduce the required isoflurane concentration. The combination increases hypotension, bradycardia and respiratory depression, which are expected in monitored anesthetic practice.
What this interaction means in plain words
Fentanyl and Isoflurane 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; Isoflurane belongs to Central Nervous System.
Why it happens
Additive CNS and cardiorespiratory depression from opioid agonism and volatile anesthetic action.
What to do
Use only with anesthesia-level monitoring and airway support, titrating the isoflurane concentration down as opioid is given. Monitor blood pressure, heart rate and ventilation.
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 Isoflurane
Frequently asked questions
Can I take Fentanyl with Isoflurane?
MediHelp rates the interaction as moderate. Fentanyl and Isoflurane 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 is commonly used with inhalational anesthetics, and together they deepen anesthesia and reduce the required isoflurane concentration. The combination increases hypotension, bradycardia and respiratory depression, which are expected in monitored anesthetic practice.
How serious is the interaction between Fentanyl and Isoflurane?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use only with anesthesia-level monitoring and airway support, titrating the isoflurane concentration down as opioid is given. Monitor blood pressure, heart rate and ventilation.
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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