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Drug interactions

Amitriptyline + Fluphenazine

Severity: Major

Amitriptyline and Fluphenazine: 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

Both agents can prolong the QT interval, so combining them increases the risk of torsades de pointes. Additive anticholinergic and sedative effects occur, and fluphenazine may raise tricyclic levels via CYP2D6 competition.

What this interaction means in plain words

Amitriptyline and Fluphenazine 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.

Amitriptyline belongs to Central Nervous System; Fluphenazine belongs to Central Nervous System.

Evidence level: Moderate

Why it happens

Additive QT prolongation and anticholinergic effects, with competition at CYP2D6.

What to do

Obtain a baseline ECG and correct electrolyte disturbances, then monitor the QTc after dose changes. Choose alternatives in patients with other QT risk factors.

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 Fluphenazine?

MediHelp rates the interaction as major. Amitriptyline and Fluphenazine 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. Both agents can prolong the QT interval, so combining them increases the risk of torsades de pointes. Additive anticholinergic and sedative effects occur, and fluphenazine may raise tricyclic levels via CYP2D6 competition.

How serious is the interaction between Amitriptyline and Fluphenazine?

MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and correct electrolyte disturbances, then monitor the QTc after dose changes. Choose alternatives in patients with other QT risk factors.

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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