Drug Interaction Report

Galantamine and Fluoxetine: Interaction Details

A pharmacist-reviewed analysis of the Galantamine and Fluoxetine interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Fluoxetine

RECONCILE
+

Galantamine

Razadyne Razadyne® (formerly available as Reminyl®) Razadyne® ER
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 180 documented Galantamine interactions, 162 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Major

What happens

Increased galantamine exposure and an increased risk of QT interval prolongation

Interaction Deep Dive

Coadministration of FLUoxetine, a CYP2D6 inhibitor and QT prolonging drug, and galantamine, a CYP2D6 substrate and QT prolonging drug, may result in increased galantamine exposure and additive effects on the QT-interval2. If concomitant use is required, monitor for galantamine toxicity including anorexia, nausea, vomiting, dizziness, arrhythmias or gastrointestinal bleeding 1 and consider periodic ECG monitoring. Discontinue use if symptoms of ventricular arrhythmia occur 2.

Why it happens (mechanism)

Inhibition of CYP2D6-mediated galantamine metabolism; additive QT interval prolongation

Literature reports

1 report — tap to read

a) Based upon in vitro studies, the major enzymes involved in galantamine metabolism are CYP3A4 and CYP2D6. FLUoxetine is a known inhibitor of CYP2D6. In a population pharmacokinetic analysis using a database of 852 Alzheimer's disease patients, several drugs which inhibit CYP2D6, including FLUoxetine (n=48), demonstrated a 25-33% decrease in galantamine clearance 1.

Common questions

Can I take Galantamine and Fluoxetine together?

Increased galantamine exposure and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Galantamine and Fluoxetine interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "probable". Good supporting evidence, though not definitively proven.

Questions for your pharmacist

  • Does my dose of Galantamine or Fluoxetine need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (2)

  1. Product Information: RAZADYNE(R) ER extended release oral capsules, oral tablets, oral solution, galantamine hBr extended release oral capsules, oral tablets, oral solution. Ortho-McNeil Neurologics,Inc, Titusville, NJ, 2007.
  2. Product Information: PROZAC(R) oral capsules, fluoxetine oral capsules. Lilly USA LLC (per FDA), Indianapolis, IN, 2023. DailyMed
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Fluoxetine

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All Fluoxetine interactions (142)
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Galantamine

Keep reading about Galantamine

All Galantamine interactions (180) Galantamine drug information
Also serious with: Levoketoconazole Bepridil Dronedarone Cisapride
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Fluoxetine + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Lithium Sida Cordifolia + 155 more
Galantamine + Activated Charcoal Grapefruit St. John's Wort 1,3-dmaa Acacia Rigidula Active Hexose Correlated Compound (ahcc) Adrafinil African Wild Potato + 162 more

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.