The short answer
Have your clinician review high-dose vitamin D and any calcium supplements with digoxin. High calcium can increase toxicity risk; a specific QT-prolongation effect or automatic change in vitamin D need is not established.
What this answer covers
Oral vitamin D supplements with digoxin; guidance directly covers colecalciferol/D3, while high-calcium susceptibility is the physiological concern.
- Supplement or preparation
- Vitamin D
- Medication ingredient
- digoxin
The supported concern is high calcium
The digoxin label identifies high calcium as a factor predisposing to toxicity. NHS guidance advises review when colecalciferol is used with digoxin because calcium-related rhythm problems can occur. This does not establish that the combination specifically prolongs the QT interval.
Review the total supplement regimen
Give the clinician the vitamin D form, amount and frequency, including high-dose intermittent prescriptions, multivitamins and calcium combinations. NHS guidance advises against adding further calcium or vitamin D products without medical advice. Appropriately prescribed deficiency treatment should not be stopped automatically.
Monitoring is different from routine replacement
Digoxin treatment does not by itself establish that you need more or less vitamin D. Ask whether calcium and kidney-function checks are appropriate for your dose and history. Taking the products a few hours apart has not been established as protection against high calcium.
Know when to seek assessment
Contact your clinician about new nausea, loss of appetite, visual changes, marked weakness or an unusually slow or irregular pulse. These may have several causes, including digoxin toxicity. Blood results must be interpreted with symptoms, kidney function and electrolytes; do not adjust digoxin yourself.
Evidence and practical considerations
Side effects & toxicity
Excess vitamin D-related high calcium can increase susceptibility to digoxin toxicity and rhythm problems.
- Exact scope
- Oral vitamin D supplements with digoxin; guidance directly covers colecalciferol/D3, while high-calcium susceptibility is the physiological concern. with Exact digoxin RxCUI3407 IN, confirmed by current RxNorm. Oral125/250microgram tablets; oral absorption evidence is not transferred to IV digoxin. Digoxin is distinct from digitoxin.
- Medication form and route
- Oral
What remains uncertain
- Bundled original QT/arrhythmia/high-calcium claim overstates evidence; separate calcium-mediated precaution supported. No universal replacement change, D2/D3 equivalence estimate or timing solution.
Factors that may matter: Exact preparation and dose; Kidney function; Baseline electrolyte status; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral digoxin tablets.
Antacids and St.John’s wort can lower concentrations. Hypokalemia, hypomagnesemia and hypercalcemia predispose to toxicity; assess electrolytes/renal function. Some substances interfere with assays without proving increased drug exposure.
How this applies: Exact medication label. Exact digoxin RxCUI3407 IN, confirmed by current RxNorm. Oral125/250microgram tablets; oral absorption evidence is not transferred to IV digoxin. Digoxin is distinct from digitoxin.
No universal nutrient spacing or vitaminD replacement need. Clinical state, assay method and formulation must be considered.
Source 2: National health-service guidance
nhs.uk · Source check Sep 10, 2026
Population: Users of oral colecalciferol.
Advises prescriber review because high calcium can cause abnormal heartbeat with digoxin; avoid adding calcium/vitaminD products without advice.
How this applies: Clinical calcium/rhythm precaution, paired with exact medication label.
D3 guidance, not a measured D2/D3 exact risk or QT-prolongation study. Does not require discontinuing appropriately prescribed replacement.
Source 3: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology.
digoxin is IN.
How this applies: Exact ingredient.
Not clinical evidence.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Research summary published |
Article revision: b05c1746c69c5781
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.