Disopyramide and Gatifloxacin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Disopyramide
Gatifloxacin
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 gatifloxacin and class IA antiarrhythmic agents, such as disopyramide, may increase the risk of QT interval prolongation due to additive effects on the QT interval. Therefore, coadministration of disopyramide and gatifloxacin should be avoided1. 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
Literature reports
1 report — tap to read
a) In clinical trials of over 44,000 patients treated with gatifloxacin, there was no cardiovascular morbidity or mortality attributable to QT prolongation with gatifloxacin treatment. This included 118 patients concurrently receiving drugs known to prolong the QT interval and 139 patients with uncorrected hypokalemia. Electrocardiogram monitoring was not performed 1.
Common questions
Can I take Disopyramide and Gatifloxacin together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Disopyramide and Gatifloxacin 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 Disopyramide or Gatifloxacin 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: TEQUIN(R) oral tablets, injection, gatifloxacin oral tablets, injection. Bristol-Myers Squibb Company, Princeton, NJ, 2006.
Keep reading about Disopyramide
Keep reading about Gatifloxacin
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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