Digoxin and Sodium Bicarbonate: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Sodium Bicarbonate
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
Reduced digoxin exposure
Interaction Deep Dive
Coadministration of digoxin and antacids may reduce digoxin exposure. Measure digoxin exposure prior to initiation of concurrent use. Increase the digoxin dose by approximately 20% to 40%, if necessary, and continue monitoring digoxin exposure12.
Why it happens (mechanism)
Reduced digoxin absorption
Literature reports
2 reports — tap to read
a) A randomized, single-dose, 6-way, crossover study with 12 fasting volunteers was conducted. Digoxin (capsules or tablets) 0.4 mg was administered with 60 mL of water, 60 mL of aluminum and magnesium hydroxide containing antacid, or 60 mL of kaolin-pectin. When compared with the control, the administration of both digoxin capsules or tablets with the antacid or the kaolin-pectin formulation reduced the peak plasma levels of digoxin, but did not significantly alter the time to peak. Neither the antacid or kaolin-pectin affected the plasma versus time concentration curve (AUC) of digoxin capsules or tablets 3.
b) Ten normal adult volunteers without cardiac, renal, gastrointestinal abnormalities, received 0.75 mg digoxin at a control time and also 60 mL of aluminum hydroxide, magnesium hydroxide or magnesium trisilicate containing antacids or kaolin-pectin at varying times. Urinary and serum digoxin samples were obtained at various times throughout a 5-day period. Bioavailability was based on an 8-hour serum digoxin concentration curve and 6 day cumulative urinary excretion of digoxin. Kaolin-pectin and magnesium trisilicate reduced the peak serum digoxin level 50% (from approximately 2.2 nanograms/mL to 1.1 nanograms/mL). Serum digoxin levels with magnesium hydroxide and aluminum hydroxide were also lower than control and were about the same as the kaolin-pectin and magnesium trisilicate doses. Mean plasma versus time concentration curve for digoxin (total absorption) for the control doses was 559 mg/min/mL, whereas it was 414 for aluminum hydroxide, 418 for magnesium hydroxide, 349 for magnesium trisilicate and 329 for kaolin-pectin. Only the magnesium trisilicate and kaolin-pectin area under the curve was significantly different from the control. The 6-day urinary excretions for the 3 antacids and kaolin-pectin were significantly different when compared to control 4.
Common questions
Can I take Digoxin and Sodium Bicarbonate together?
Reduced digoxin exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Digoxin and Sodium Bicarbonate 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Digoxin or Sodium Bicarbonate 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 (4)
- Product Information: LANOXIN(R) oral tablets, digoxin oral tablets. Concordia Pharmaceuticals Inc (per FDA), Kansas City, MO, 2019. DailyMed
- Product Information: DIGOXIN oral tablets, digoxin oral tablets. Aurobindo Pharma USA, Inc. (per Dailymed), East Windsor, NJ, May. DailyMed
- Allen MD, Greenblatt DJ, Harmatz JS, et al: Effect of magnesium-hydroxide and kaolin-pectin on absorption of digoxin from tablets and capsules. J Clin Pharmacol 1981; 21:26-30.
- Brown DD & Juhl RP: Decreased bioavailability of digoxin due to antacids and kaolin-pectin. N Engl J Med 1976; 295:1034-1037. PubMed
Keep reading about Sodium Bicarbonate
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.
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