ModerateFluoroquinolone antibacterials×Cardiac glycosides (digitalis)
Updated · Methodology
Mechanism
In 10–15% of patients, gut flora (mainly Eubacterium lentum) metabolises part of digoxin to inactive products. Ciprofloxacin suppresses this flora — digoxin levels rise by 30–80% in those patients, increasing toxicity risk.
Symptoms
Nausea, vomiting, loss of appetite, confusion, yellow-green halos around lights, arrhythmia (bigeminy, AV block). Symptoms appear earlier in older patients and chronic kidney disease.
Management
For short ciprofloxacin courses (5–7 days), most patients need no adjustment. In older patients and chronic kidney disease, check digoxin level at 5–7 days after antibiotic start. With toxicity signs, reduce dose by 25%. Alternative antibiotics: a cephalosporin (minimal gut flora impact).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
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Sources
- Lexicomp: Lexicomp Drug Interactions (2024)– Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- Pharmaceutical Press: Stockley's Drug Interactions, 12th edition (2024)– Preston CL (ed.). Stockley's Drug Interactions. 12th ed. London: Pharmaceutical Press; 2024