Chloroquine and Ciprofloxacin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ciprofloxacin
No brand names on recordChloroquine
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
Increased ciprofloxacin urinary excretion and an increased risk of QT interval prolongation and torsade de pointes
Interaction Deep Dive
Avoid concomitant use of ciprofloxacin and chloroquine (QT prolonging agent) due to increased risk factors for QT prolongation or torsade de pointes12. Coadministration may also reduce ciprofloxacin exposure. When administering chloroquine and ciprofloxacin together, monitor therapeutic efficacy of ciprofloxacin. Consider administering ciprofloxacin hours before chloroquine to reduce the effect of chloroquine on ciprofloxacin excretion 3.
Why it happens (mechanism)
Unknown; additive QT interval prolongation
Literature reports
1 report — tap to read
a) In a single-center, prospective study, concomitant use of chloroquine and ciprofloxacin significantly increased the rate of ciprofloxacin excretion and cumulative urine ciprofloxacin compared with ciprofloxacin alone in healthy male volunteers (n=8). During phase one, subjects (between 19 and 31 years of age) each received one dose of oral ciprofloxacin 500 mg followed by a 2-week washout period. In the second phase, patients were given oral chloroquine 600 mg together with oral ciprofloxacin 500 mg. Urine samples were collected 0, 1, 2, 4, 8, 12, and 24 hours after administration during both phases. Analysis showed that at 0.5 hours, the urinary excretion of ciprofloxacin increased from 0.09 mg/mL in phase 1 to 5.2 mg/mL in phase 2. Ciprofloxacin urinary recovery also increased from 0.1% when ciprofloxacin was administered alone to 1.1% during concomitant administration with chloroquine 3.
Common questions
Can I take Chloroquine and Ciprofloxacin together?
Increased ciprofloxacin urinary excretion and an increased risk of QT interval prolongation and torsade de pointes Always confirm with your pharmacist or prescriber before making any change.
How serious is the Chloroquine and Ciprofloxacin interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Chloroquine or Ciprofloxacin 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: CIPROFLOXACIN oral tablets, ciprofloxacin oral tablets. Solco Healthcare US, LLC (per Dailymed), Somerset, NJ, 2024. DailyMed
- Product Information: CIPROFLOXACIN HYDROCHLORIDE oral tablets, ciprofloxacin hydrochloride oral tablets. Aurobindo Pharma USA, Inc (per Dailymed), East Windsor, NJ, 2024. DailyMed
- Ilo CE, Ezejiofor NA, Agbakoba N, et al: Effect of chloroquine on the urinary excretion of ciprofloxacin. Am J Ther 2008; 15(5):419-422. PubMed
Keep reading about Ciprofloxacin
Keep reading about Chloroquine
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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