Digoxin
Also known as: Cardoxin · Lanoxin PG · digoxinum · digoxosidum · digitalis
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| CHF with atrial fibrillation in dogs with normal renal function | 0.005-0.0075 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Initial dosing for dogs weighing less than 20 kg | 0.005-0.011 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Initial dosing for dogs weighing more than 20 kg | 0.22 mg/m2 (NOT mg/kg) PO q12h | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of dilated cardiomyopathy patients with atrial fibrillation | 0.0025 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of atrial fibrillation | 0.003-0.005 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Refractory heart failure or atrial fibrillation (if pimobendan unavailable) | 0.005 mg/kg PO twice a day | PO | q12h | — | 🌎 NA |
| Supraventricular arrhythmias | 0.22 mg/m2 (NOT mg/kg) PO q12h | PO | q12h | — | 🌎 NA |
| Management of supraventricular tachyarrhythmias | 2.5-3.5 μg/kg (based on lean body weight; decrease dose by 10% for elixir). Maximum dose 0.25 mg/dog. Start at lower end of dose range and up-titrate carefully. | PO | q12h | Long-term | 🌍 EU |
| Management of supraventricular tachyarrhythmias (Emergency/Rare) | 2.2-4.4 μg/kg | IV | q12h | As needed | 🌍 EU |
- CHF with atrial fibrillation in dogs with normal renal function: Trough level of 0.8-1.2 nanograms/mL is the recommended target.
- Initial dosing for dogs weighing less than 20 kg: Results in therapeutic range by second day. Monitor levels 3-5 days later.
- Initial dosing for dogs weighing more than 20 kg: Results in therapeutic range by second day. Monitor levels 3-5 days later.
- Adjunctive treatment of dilated cardiomyopathy patients with atrial fibrillation: Loading dose usually not given. Trough therapeutic level is 0.8-1.2 ng/mL.
- Refractory heart failure or atrial fibrillation (if pimobendan unavailable): Start with a low dose and round down if needed.
- Management of supraventricular tachyarrhythmias: Dose based on lean body weight. Decrease dose by 10% for elixir.
- Management of supraventricular tachyarrhythmias (Emergency/Rare): Only use IV if essentially indicated. Administer very slowly.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Dilated cardiomyopathy or advanced atrioventricular valve insufficiency | 0.007 mg/kg PO every other day | PO | q48h | — | 🌎 NA |
| Starting dose for normal cats weighing less than 3 kg | 1/4th of a 0.125 mg tablet administered every other day | PO | q48h | — | 🌎 NA |
| Starting dose for normal cats weighing 3 to 6 kg | 1/4th of a tablet every day | PO | q24h | — | 🌎 NA |
| Starting dose for normal cats weighing more than 6 kg | 1/4th of a tablet every day to q12h | PO | q12h-q24h | — | 🌎 NA |
| Management of supraventricular tachyarrhythmias | 10 μg/kg (equating to 1/4 of a 125 μg tablet). Start at lower dose range and titrate up. | PO | q24-48h | Long-term | 🌍 EU |
| Management of supraventricular tachyarrhythmias (Emergency/Rare) | 1-1.6 μg/kg | IV | q12h | As needed | 🌍 EU |
- Dilated cardiomyopathy or advanced atrioventricular valve insufficiency: Use lean body weight. Measure serum level 10+ days later, 8-10 hours after dosing. Therapeutic level: 1-2 ng/mL.
- Starting dose for normal cats weighing less than 3 kg: Tablets are better tolerated than the alcohol-based elixir.
- Starting dose for normal cats weighing 3 to 6 kg: Using 0.125 mg tablet.
- Starting dose for normal cats weighing more than 6 kg: Using 0.125 mg tablet.
- Management of supraventricular tachyarrhythmias: Cats are highly sensitive to toxicity.
- Management of supraventricular tachyarrhythmias (Emergency/Rare): Only use IV if essentially indicated. Administer very slowly.
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Dilated cardiomyopathy in Hamsters | 0.05-0.1 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
Ferrets
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Dilated cardiomyopathy | 0.01 mg/kg PO once daily initially | PO | q24h | — | 🌎 NA |
| Maintenance | 0.005-0.01 mg/kg PO once to twice daily | PO | q12h-q24h | — | 🌎 NA |
| Dilated cardiomyopathy long-term maintenance | 0.01 mg/kg q24h | PO | q24h | Long-term | 🌎 NA |
- Dilated cardiomyopathy: Use oral liquid. May increase to twice daily if necessary.
- Maintenance: Using the elixir; monitor blood levels if possible.
- Dilated cardiomyopathy long-term maintenance: Used with furosemide (2 mg/kg q12h) and enalapril (0.5 mg/kg q48h).
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Emergency stabilization | 0.02-0.5 mg/kg q12h for 2-3 days, then decreased to 0.01 mg/kg q12-24h | PO/IM/IV | q12h then q12-24h | 2-3 days initial, then maintenance | 🌎 NA |
- Emergency stabilization: Because of very small therapeutic margin, best used for emergency stabilization rather than long-term therapy. Consider switching to an ACE inhibitor.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Loading dose | 11 micrograms/kg IV given slowly or in divided doses, or 44 micrograms/kg PO | IV/PO | Once | — | 🌎 NA |
| Maintenance Dose | 2.2 micrograms/kg IV every 12h or 11 micrograms/kg PO every 12 hours | IV/PO | q12h | — | 🌎 NA |
- Loading dose: ARCI UCGFS Class 4 Drug
- Maintenance Dose: Maintain plasma concentrations between 0.5-2 ng/mL.
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Normalize atrial rate | 0.25 mg/100 lbs body weight | PO | Titrate to effect | — | 🌎 NA |
- Normalize atrial rate: Not destroyed in rumen; not excreted in milk.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Digoxin is a cardiac glycoside used primarily for its positive inotropic (increased contractility) and negative chronotropic (decreased heart rate) effects. It is utilized in veterinary medicine to treat congestive heart failure (CHF) and supraventricular tachyarrhythmias, such as atrial fibrillation or flutter.
Clinical Pearls:
- Narrow Therapeutic Index: The margin between a therapeutic dose and a toxic dose is extremely small. Careful dosing and therapeutic drug monitoring (TDM) are essential.
- Shifting Paradigm: While historically a cornerstone of CHF management, digoxin is no longer considered first-line therapy for heart failure in dogs and cats due to the availability of safer and more effective inodilators like pimobendan. It is now primarily reserved for rate control in atrial fibrillation, often used adjunctively with diltiazem.
- Dosing Basis: Because digoxin does not distribute well into fat or ascitic fluid, dosing must be based on lean body weight.
- Species Sensitivity: Cats are highly sensitive to digoxin toxicity compared to dogs.
Mechanism of action
Digoxin exerts its effects through the reversible inhibition of the Na⁺/K⁺-ATPase pump in the myocardial cell membrane.
- Positive Inotropy (Contractility): Inhibition of Na⁺/K⁺-ATPase → Increased intracellular Na⁺ → Decreased driving force for the Na⁺/Ca²⁺ exchanger (NCX) → Decreased Ca²⁺ extrusion → Increased intracellular Ca²⁺ → Increased Ca²⁺ uptake into the sarcoplasmic reticulum. Upon the next action potential, more Ca²⁺ is released, leading to increased myocardial contractility.
- Negative Chronotropy/Dromotropy (Heart Rate/Conduction): Digoxin increases vagal (parasympathetic) tone → Decreased conduction velocity through the AV node and prolonged effective refractory period (ERP) → Slowed ventricular response rate in supraventricular arrhythmias.
- Neurohormonal Effects: At low doses, digoxin restores baroreceptor sensitivity, which decreases sympathetic outflow and reduces the neurohormonal activation seen in heart failure.
Safety & warnings
Contraindications
- Ventricular fibrillation
- Digitalis intoxication
- Hypertrophic cardiomyopathy in cats (relative contraindication, may increase myocardial oxygen demand and dynamic outflow obstruction)
- Frequent ventricular arrhythmias
- Atrioventricular (AV) block
- Feline hypertrophic cardiomyopathy
- Hypokalaemia
Adverse effects
- Cardiac arrhythmias (complete or incomplete heart block, bigeminy, ST segment changes, paroxysmal ventricular or atrial tachycardias, multifocal VPCs)
- Mild GI upset
- Anorexia
- Weight loss
- Diarrhea
- Vomiting (especially associated with IV injections)
- Diarrhoea
- Depression
- Arrhythmias (AV block, bigeminy, paroxysmal ventricular or atrial tachycardias with block, multiform VPCs)
- Vasoconstriction (with IV administration)
Precautions
Extreme Caution: Patients with glomerulonephritis and heart failure, or with idiopathic hypertrophic subaortic stenosis (IHSS).
- Caution: Severe pulmonary disease, hypoxia, acute myocarditis, myxedema, acute myocardial infarction, frequent VPCs, V-tach, chronic constrictive pericarditis, or incomplete AV block.
- Renal Disease: Principally eliminated by the kidneys; use with caution and monitor serum levels closely in patients with renal impairment.
- Electrolyte/Endocrine Imbalances: Animals that are hypernatremic, hypokalemic, hypercalcemic, hyper- or hypothyroid may require smaller dosages; monitor carefully.
- Cardioversion: Elective cardioversion of patients with atrial fibrillation should be postponed until digoxin has been withheld for 1-2 days.
- Dosing Weight: Dosing is generally based upon lean body weight as digoxin does not distribute well into ascitic fluid or fat.
Drug interactions
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels in dogs
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels (data conflicts); additive negative effects on AV conduction
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects; hypokalemia predisposes to digitalis toxicity
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels; rule of thumb is to decrease digoxin dose by 50% if used together
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels; additive negative effects on AV conduction
Additive negative effects on AV conduction, complete heart block possible
May decrease serum levels of digoxin independent of route of digoxin dosing
May predispose the patient to digitalis toxicity via electrolyte imbalances (e.g., hypokalemia)
May enhance or decrease the toxic effects of digoxin
Patients on digoxin that receive thyroid replacement therapy may need their digoxin dosage adjusted
May decrease digoxin absorption from the GI tract
May increase serum level, decrease elimination rate, or enhance toxic effects
Can cause hypokalaemia, which strongly predisposes to digoxin toxicity
May increase serum level, decrease elimination rate, or enhance toxic effects
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May cause hypokalaemia, which enhances the toxic effects of digoxin
May cause hypokalaemia, which enhances the toxic effects of digoxin
Monitoring
- Serum digoxin levels (Trough levels recommended: Dogs 0.8-1.2 ng/mL; Cats 0.9-2 ng/mL; Other species 0.5-2 ng/mL. Wait at least 6 days after starting therapy to reach steady-state)
- Appetite and body weight
- Cardiac rate and ECG changes
- Serum electrolytes (especially potassium)
- Renal function tests
- Clinical efficacy for CHF (improved perfusion, decreased edema)
- Serum digoxin levels (check after 7-10 days, sample taken 6-8 hours post-pill. Ideal trough therapeutic level: 0.6-1.2 ng/ml)
- ECG (monitor for AV block and ventricular arrhythmias)
- Serum potassium levels (hypokalaemia increases toxicity risk)
- Renal function (BUN, Creatinine)
Pharmacokinetics
Half-life
Absorption
Variable depending on the oral dosage form. Food may delay, but not alter, the extent of absorption in most species. In cats, food reportedly decreases the amount absorbed by 50% after tablet administration. Peak serum levels occur within 45-60 minutes (elixir) and 90 minutes (tablet).
Distribution
Widely distributed with highest levels in kidneys, heart, intestine, stomach, liver, and skeletal muscle. Lowest concentrations in brain and plasma. Does not significantly enter ascitic fluid. Approximately 20-30% bound to plasma proteins.
Metabolism
Metabolized slightly.
Elimination
Primary method of elimination is renal excretion (both glomerular filtration and tubular secretion). Dosage adjustments are required in significant renal disease.
Overdose
Acute Toxicity: In dogs, the acute toxic dose after IV administration is reported to be 0.177 mg/kg.
Treatment of Toxicity:
- Chronic Toxicity: Often resolves by temporarily stopping the drug and reevaluating the dosage regimen.
- Acute Ingestion: If recent and no cardiotoxic/neurologic signs are present, empty the stomach followed by activated charcoal. Repeated charcoal administration may be beneficial due to enterohepatic recirculation. Anion-exchange resins (colestipol, cholestyramine) can reduce absorption but are rarely available.
- Supportive Care: Continuous ECG monitoring, correct acid-base/hypoxia/fluid/electrolyte imbalances. Note: Potassium use in normokalemic patients is controversial and requires expertise.
- Antiarrhythmics: Lidocaine and phenytoin are commonly used for life-threatening digitalis-induced arrhythmias. Atropine may treat sinus bradycardia, SA arrest, or AV block.
- Antidote: Digoxin immune Fab (ovine antibodies) binds directly to the drug, inactivating it. It is highly effective but very expensive, and veterinary experience is limited.
Available products
Formulations
- Injection
- Tablets
- Oral Solution
- 62.5 μg oral tablet
- 125 μg oral tablet
- 250 μg oral tablet
- 50 μg/ml oral elixir
- 250 μg/ml injectable
Veterinary
- Veterinary-labeled products are no longer available commercially in the USA.
Human-labeled
- Digoxin Solution for Injection: 250 micrograms/mL (0.25 mg/mL) and 100 micrograms/mL (0.1 mg/mL) (Lanoxin, generic)
- Digoxin Oral Tablets: 125 micrograms (0.125 mg) and 250 micrograms (0.25 mg) (Lanoxin, generic)
- Digoxin Oral Solution: 50 micrograms/mL (0.05 mg/mL) (generic)
- Lanoxin 62.5 μg, 125 μg, 250 μg tablets
- Lanoxin PG 50 μg/ml elixir
- Lanoxin 250 μg/ml injectable
Regulatory status
POM
POM-V / POM
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets, capsules, elixir, and injection at room temperature (15-30°C) and protect from light. Stable at pH 5-8; hydrolyzed in solutions with a pH of less than 3.
Client information
Digoxin is a potent heart medication used to help the heart pump more effectively and control irregular heartbeats.
- Strict Dosing: Give this medication exactly as prescribed. Do not change the dose or stop the medication without consulting your veterinarian, as the difference between a helpful dose and a toxic dose is very small.
- Watch for Toxicity: Contact your veterinarian immediately if your pet shows any signs of toxicity, which often start with gastrointestinal upset. Watch for loss of appetite, vomiting, diarrhea, lethargy, depression, or changes in behavior.
- Missed Doses: If you miss a dose, do not double up on the next dose. Give the next dose at the regularly scheduled time.
- Monitoring: Your pet will need regular blood tests to check the level of digoxin in their blood, as well as kidney function and electrolyte levels, to ensure the dose remains safe and effective.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.