Drug interactions
Carbamazepine + Fentanyl transdermal
Severity: Major
Carbamazepine and Fentanyl transdermal: 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
Carbamazepine lowers fentanyl levels, risking reduced analgesia or withdrawal. After carbamazepine is stopped, fentanyl levels can climb and cause serious respiratory depression.
What this interaction means in plain words
Carbamazepine and Fentanyl transdermal 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.
Why it happens
Carbamazepine induces CYP3A4, increasing fentanyl clearance.
What to do
Monitor pain control and withdrawal and adjust the patch dose. On stopping carbamazepine, reduce the fentanyl dose and monitor for respiratory depression for an extended period.
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?
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References
Other interactions of Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Carbamazepine with Fentanyl transdermal?
MediHelp rates the interaction as major. Carbamazepine and Fentanyl transdermal 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. Carbamazepine lowers fentanyl levels, risking reduced analgesia or withdrawal. After carbamazepine is stopped, fentanyl levels can climb and cause serious respiratory depression.
How serious is the interaction between Carbamazepine and Fentanyl transdermal?
MediHelp rates it major, 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 and adjust the patch dose. On stopping carbamazepine, reduce the fentanyl dose and monitor for respiratory depression for an extended period.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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