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Drug interactions

Amitriptyline + Fentanyl transdermal

Severity: Major

Amitriptyline and Fentanyl transdermal: major 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 combined with a sedating tricyclic increases CNS and respiratory depression. Serotonergic toxicity is also possible.

What this interaction means in plain words

Amitriptyline 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.

Evidence level: Moderate

Why it happens

Additive CNS depression, with added serotonergic activity.

What to do

Reserve for patients without alternatives, use the lowest doses and monitor sedation and respiratory rate, especially after dose changes. Counsel on avoiding alcohol and other sedatives.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Amitriptyline with Fentanyl transdermal?

MediHelp rates the interaction as major. Amitriptyline 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. Fentanyl combined with a sedating tricyclic increases CNS and respiratory depression. Serotonergic toxicity is also possible.

How serious is the interaction between Amitriptyline 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: Reserve for patients without alternatives, use the lowest doses and monitor sedation and respiratory rate, especially after dose changes. Counsel on avoiding alcohol and other sedatives.

What other medicines interact with Amitriptyline?

MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.

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