Digoxin and Demeclocycline: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Demeclocycline
Digoxin
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 digoxin levels and digoxin toxicity (nausea, vomiting, cardiac arrhythmias)
Interaction Deep Dive
Coadministration of tetracyclines, such as demeclocycline, and digoxin can result in increased digoxin levels3. In approximately 10% to 15% of patients, digoxin is converted to inactive metabolites by colonic bacteria within the gut. Inactivation of these enteric flora by antibiotics results in a significant increase in absorption of the parent compound digoxin 1
Why it happens (mechanism)
Inhibition of bacterial inactivation of digoxin resulting in increased digoxin bioavailability and digoxin toxicity
Literature reports
1 report — tap to read
a) Approximately 10% of patients receiving digoxin convert 40% or more of the drug to cardio-inactive metabolites 2. This inactivation may be attributed to gastrointestinal bacteria. Antibiotic therapy introduced to these patients has caused a marked decrease in digoxin reduction products and a marked rise in digoxin absorption and serum levels. It is concluded that changes in the enteric flora by antibiotics may alter the state of digitalization. Although data for the interaction between digoxin and doxycycline is unavailable, elevated serum digoxin concentrations by as much as 43 to 116% were observed after a 5-day course of tetracycline in 3 volunteers who produced large amounts of digoxin reduction products 1.
Common questions
Can I take Digoxin and Demeclocycline together?
Increased digoxin levels and digoxin toxicity (nausea, vomiting, cardiac arrhythmias) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Digoxin and Demeclocycline interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
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 Digoxin or Demeclocycline 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)
- Lindenbaum J, Rund DG, Butler VP, et al: Inactivation of digoxin by the gut flora: reversal by antibiotic therapy. N Engl J Med 1981a; 305:789-794. PubMed
- Product Information: LANOXICAPS(R) oral solution in capsules, digoxin oral solution in capsules. Cardinal Health, St. Petersburg, FL, 2005. DailyMed
- Roos TC & Merk HF: Important drug interactions in dermatology. Drugs 2000; 59(2):181-192. PubMed
Keep reading about Demeclocycline
Keep reading about Digoxin
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