Digoxin and Calcium: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Digoxin
Calcium
No brand names on record
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
A serious risk of arrhythmia and cardiovascular collapse
Interaction Deep Dive
Coadministration of digoxin and calcium, especially if given by rapid, IV injection in patients receiving digoxin may produce serious arrhythmias132, and cases have been reported following bolus IV calcium administrations 4. Use caution if concurrent use of IV calcium is warranted, administer slowly over several hours, and monitor patients closely. Due to the risk of developing hypercalcemia and subsequent cardiac arrhythmias, coadministration of oral calcium acetate is not recommended in patients receiving digitalis 5. Use of IV calcium compounds in digitalized patients is recommended only if it is clearly indicated 67.
Why it happens (mechanism)
Additive or synergistic cardiac effects
Literature reports
2 reports — tap to read
a) The relationship between calcium and digitalis is documented in animal studies, though controversy does exist over whether it is synergistic, additive or if a relationship exists at all 8. Methods of evaluation have also been quite diverse. Two case reports have described serious interactions with intravenous (IV) calcium use in digitalized patients. The first case was a 32 year-old white female with no mention of heart disease who underwent a cholecystectomy. She was given a total of 15 ml of Digalen® over six days for tachycardia, low blood pressure and extrasystoles. The tachycardia remained persistent and 10 mL calcium gluconate was given intravenously. Two minutes later the patient suffered cardiac and respiratory arrest and died. The second patient was a 55 year-old white male with admitting diagnosis of multiple myeloma or hyperparathyroidism. Thyroid surgery was performed and 8.5 ml Digalen® was given over 20 hours (no stated reason). Two days later a fine tremor developed, 10 mL of calcium chloride was given intravenously and a few minutes later the patient died of cardiovascular collapse 49.
b) A retrospective study of 112 cases with possible digoxin toxicity evaluated 40 cases based on defined criteria of digoxin toxicity. Two cases of toxicity were thought to be due to the administration of calcium gluconate intravenously. Both patients were digitalized, one on lanatoside C, the other on digoxin, and both were hypocalcemic. One patient died 10 minutes after receiving the calcium, the other received calcium for three days (rate not specified) and developed apparent digoxin toxicity, but did not expire 4.
Common questions
Can I take Digoxin and Calcium together?
A serious risk of arrhythmia and cardiovascular collapse Always confirm with your pharmacist or prescriber before making any change.
How serious is the Digoxin and Calcium 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 Digoxin or Calcium 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 (9)
- Product Information: DIGOXIN oral tablets, digoxin oral tablets. Aurobindo Pharma USA, Inc. (per Dailymed), East Windsor, NJ, May. DailyMed
- Product Information: DIGOXIN intravenous injection, digoxin intravenous injection. Hikma Pharmaceuticals USA Inc. (per Dailymed), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: LANOXIN® intravenous, intramuscular injection, digoxin intravenous, intramuscular injection. Covis Pharma (per FDA), King of Prussia, PA, 2025. DailyMed
- Shrager MW: Digitalis intoxication: a review and report of forty cases, with emphasis on etiology. Arch Intern Med 1957; 100:881-893. PubMed
- Product Information: PHOSLO(R) oral gelcaps, calcium acetate oral gelcaps. Fresenius Medical Care NA, Waltham, MA, 2006. DailyMed
- Product Information: calcium chloride injection, calcium chloride injection. Hospira,Inc. Lake Forest, IL, 2004. DailyMed
- Product Information: calcium gluconate IV injection, 10%, calcium gluconate IV injection, 10%. American Regent Laboratories,Inc, Shirley, NY, 2000. DailyMed
- Nola GT, Pope S, & Harrison DC: Assessment of the synergistic relationship between serum calcium and digitalis. Am Heart J 1970; 79:499-507. PubMed
- Bower JO & Mengle HAK: The additive effects of calcium and digitalis: a warning with a report of two deaths. JAMA 1936; 106:1151-1153.
Keep reading about Digoxin
Keep reading about Calcium
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