The short answer
Extra potassium loss from horsetail with digoxin is not established. The available short trial found no significant urinary potassium change, but low potassium from any cause can increase digoxin toxicity.
What this answer covers
E.arvense oral aerial-part preparations with digoxin; the study used a defined dry extract in healthy men.
- Supplement or preparation
- Equisetum arvense
- Medication ingredient
- digoxin
The horsetail trial did not show potassium loss
A small crossover trial used900mg daily of a defined E.arvense aerial-part extract for four days. It found a diuretic fluid-balance effect without significant urinary potassium or sodium change. Digoxin users and patients with relevant heart or kidney disease were not the studied population.
A diuretic effect is not enough to prove this claim
Increasing urine output does not automatically demonstrate clinically important potassium loss. The trial’s short duration and healthy participants also prevent it from proving long-term safety. Other horsetail species, extracts and blends cannot be treated as the tested product.
Digoxin makes electrolyte assessment important
Digoxin’s label identifies low potassium and low magnesium as factors increasing toxicity risk. Review horsetail and other products with the prescribing team, especially if you also take a diuretic. This precaution does not mean digoxin itself has been shown to amplify horsetail-related potassium loss.
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
The inspected E.arvense trial does not establish potassium depletion or an added low-potassium interaction with digoxin.
- Exact scope
- E.arvense oral aerial-part preparations with digoxin; the study used a defined dry extract in healthy men. 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
- No exact co-use trial or potassium-loss signal in short healthy trial; separate digoxin susceptibility is not proof of the original claim.
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: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 36 healthy men; heart, kidney disease and hypertension excluded.
Diuretic fluid-balance effect without significant urinary sodium or potassium change; safety laboratory values remained normal.
How this applies: Applicability is limited to the stated exact medication, preparation and endpoint; other-drug evidence is indirect.
Short healthy trial, no digoxin or bumetanide co-use. HCTZ comparator does not make the herb a sodium/potassium-wasting equivalent.
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: abc03071d2c516e0
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.
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Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.