Drug interactions
Amobarbital + Fentanyl
Severity: Major
Amobarbital and Fentanyl: major interaction.
Last updated Sources: US FDA label
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
Barbiturates and opioids together increase the risk of profound sedation and respiratory depression. Amobarbital also induces CYP3A4, which can lower fentanyl levels and reduce analgesia, and levels may rise after the barbiturate is stopped.
What this interaction means in plain words
Amobarbital and Fentanyl 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.
Amobarbital belongs to Central Nervous System; Fentanyl belongs to Musculoskeletal.
Why it happens
Additive CNS depression plus CYP3A4 induction by amobarbital increasing fentanyl clearance.
What to do
Avoid if possible; otherwise use the lowest doses and monitor respiration and sedation. Adjust fentanyl dose on starting or stopping amobarbital.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Amobarbital and Fentanyl, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
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 Amobarbital
- Amobarbital + Calcium / magnesium / potassium / sodium oxybates Contraindicated
- Amobarbital + Doravirine Contraindicated
- Amobarbital + Elbasvir / grazoprevir Contraindicated
- Amobarbital + Isavuconazonium Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amobarbital + Lonafarnib Contraindicated
Frequently asked questions
Can I take Amobarbital with Fentanyl?
MediHelp rates the interaction as major. Amobarbital and Fentanyl 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. Barbiturates and opioids together increase the risk of profound sedation and respiratory depression. Amobarbital also induces CYP3A4, which can lower fentanyl levels and reduce analgesia, and levels may rise after the barbiturate is stopped.
How serious is the interaction between Amobarbital and Fentanyl?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; otherwise use the lowest doses and monitor respiration and sedation. Adjust fentanyl dose on starting or stopping amobarbital.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
