Citalopram and Moxifloxacin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Moxifloxacin
Citalopram
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.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Both citalopram and moxifloxacin are known to cause QT interval prolongation21 and concomitant use is not recommended 3. Although the interaction has not been studied, the coadministration of citalopram with moxifloxacin may cause an increased risk of QT prolongation and torsade de pointes. If concomitant use is required, monitor for ECG changes. Do not exceed citalopram doses of 40 mg/day and discontinue citalopram in patients who have persistent QTc measurements greater than 500 milliseconds 2. Do not exceed the recommended dose or infusion rate of moxifloxacin 1.
Why it happens (mechanism)
Additive effects QT interval prolongation
Common questions
Can I take Citalopram and Moxifloxacin together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Citalopram and Moxifloxacin 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Citalopram or Moxifloxacin 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 (3)
- Product Information: AVELOX(R) film coated oral tablets, solution for IV injection, moxifloxacin hydrochloride film coated oral tablets, solution for IV injection. Merck & Co, Inc, Whitehouse Station, NJ, 2011.
- Product Information: CELEXA(R) oral tablets, citalopram oral tablets. Allergan USA Inc (per FDA), Madison, NJ, 2023. DailyMed
- Product Information: Celexa(R) oral tablets, solution, citalopram hydrobromide oral tablets, solution. Forest Pharmaceuticals, Inc. (per FDA), St. Louis, MO, 2012. DailyMed
Keep reading about Moxifloxacin
Keep reading about Citalopram
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist