Quinidine and Ofloxacin Otic: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ofloxacin Otic
Quinidine
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
Concomitant use of ofloxacin and class IA antiarrhythmic agents, such as quinidine, may increase the risk of QT interval prolongation due to additive effects on the QT interval. Therefore, coadministration of ofloxacin and quinidine should be avoided. Because geriatric patients may be particularly sensitive to QT prolongation associated with drug effects, appropriate precautions should be taken when coadministering these drugs to this patient population1. If concurrent therapy is required, consider monitoring the patient closely for prolongation of the QT interval.
Why it happens (mechanism)
Additive effects on the QT interval
Common questions
Can I take Quinidine and Ofloxacin Otic together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Quinidine and Ofloxacin Otic 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.
Questions for your pharmacist
- Does my dose of Quinidine or Ofloxacin Otic 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 (1)
- Product Information: FLOXIN(R) oral tablets, ofloxacin oral tablets. Ortho-McNeil-Janssen Pharmaceuticals, Inc. Raritan, NJ, 2008. DailyMed
Keep reading about Ofloxacin Otic
Keep reading about Quinidine
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.
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