Digoxin: veterinary dose and monograph

At a glance

Drug class

Cardiovascular

Also known as

Lanoxin, Cardoxin

Species with doses

Dogs, Cats, Horses and Ferrets

General dose range

0.003–0.011 mg/kg PO q12h (dog) / q48h (cat) — check the species tables for the indication

Routes

PO, IV

Last reviewed

1 October 2026

Indications

• Rate control of atrial fibrillation / supraventricular tachyarrhythmia
• Adjunct in selected dilated cardiomyopathy / CHF

Digoxin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• AF rate control / CHF (oral maintenance): Dose on LEAN body weight. Papich 5e: 0.005–0.011 mg/kg q12h PO (dogs >20 kg: 0.22 mg/m² q12h; subtract 10% for elixir); atrial fibrillation 0.005 mg/kg q12h, may be combined with diltiazem 3 mg/kg q12h. Plumb’s p.402: AF 0.003–0.005 mg/kg q12h (Hogan 2004) or 0.005–0.0075 mg/kg q12h (Keene & Bonagura 2009); DCM 0.0025 mg/kg q12h. Trough 0.8–1.2 ng/mL, 3–5 days after starting.
• Rapid digitalization (IV — inpatient only): Papich 5th ed: "Rapid digitalization: 0.0055–0.011 mg/kg q1h IV to effect." ⚠ ECG monitoring is mandatory — the therapeutic index is narrow and IV loading is the highest-risk way to give digoxin. Reserve for hospitalised patients; oral maintenance above is the usual route.

Cats

• DCM / advanced AV-valve disease (not HCM): Papich 5e: 0.008–0.01 mg/kg q48h PO (about ¼ of a 0.125 mg tablet per cat). Plumb’s p.402 (Ware & Keene 2000): 0.007 mg/kg PO every other day on lean weight; level at 10+ days, 8–10 h post-dose, target 1–2 ng/mL. Generally contraindicated in feline hypertrophic cardiomyopathy. Tablets are better tolerated than the alcohol elixir.

Horses

• Atrial fibrillation rate control / CHF: Plumb’s p.402 (Mogg 1999): maintenance 11 µg/kg PO q12h (loading 44 µg/kg PO or 11 µg/kg IV slowly); keep plasma 0.5–2 ng/mL. Papich 5e: 15 µg/kg q12h PO or 2 µg/kg IV q12h. Monitor serum digoxin and potassium. ARCI Class 4.
• IV maintenance: Papich 5e: 2 µg/kg IV q12h. Plumb’s p.402 (Mogg 1999): 2.2 µg/kg IV q12h. Narrow therapeutic index — monitor levels and ECG.

Ferrets

• Dilated cardiomyopathy: Plumb’s p.402: 0.005–0.01 mg/kg PO once to twice daily using the elixir (Williams 2000); 0.01 mg/kg once daily initially, may increase to twice daily (Hoeffer 2000). Monitor as in dogs and cats.

Contraindications

Ventricular arrhythmias, AV block, hypertrophic cardiomyopathy with outflow obstruction, hypokalaemia, significant renal impairment (renal excretion). Avoid loading doses.

Adverse effects

• Anorexia, vomiting, diarrhoea — often the FIRST signs of toxicity
• Arrhythmias of any type — AV block, VPCs, bradycardia
• Lethargy, depression

Drug interactions

• NARROW THERAPEUTIC INDEX — Plumb's advises enhanced monitoring whenever any of the drugs below (or others in the same class) are added to a patient stabilised on digoxin
• May REDUCE digoxin levels: aminosalicylic acid, antacids, chloramphenicol (dogs), cholestyramine, cimetidine, metoclopramide, oral neomycin, phenobarbital, St John's wort, sucralfate, sulfasalazine, penicillamine
• May RAISE levels / slow elimination / enhance toxicity: amiodarone, anticholinergics, ACE inhibitors (captopril and others), coleus, cyclosporine, diazepam, diltiazem (data conflict), erythromycin, furosemide, hawthorn, ketoconazole, itraconazole, omeprazole and other PPIs, quinidine, reserpine, succinylcholine, tetracycline, verapamil
• Quinidine specifically: the rule of thumb is to DECREASE the digoxin dose by 50% if used together
• Beta-blockers: additive negative effects on AV conduction — complete heart block is possible
• Calcium-channel blockers (diltiazem and others): additive negative effects on AV conduction
• Drugs affecting potassium/electrolyte balance (diuretics, amphotericin B, glucocorticoids, laxatives, glucagon, high-dose IV dextrose, dextrose/insulin infusions, furosemide, thiazides): HYPOKALAEMIA predisposes to digoxin toxicity — this is the commonest real-world precipitant
• Spironolactone: may either enhance or decrease the toxic effects of digoxin
• Thyroid supplements: patients started on thyroid replacement may need their digoxin dose adjusted

Pregnancy and lactation

Crosses the placenta; use only if clearly needed and monitor levels.

Monitoring

• Serum digoxin 0.8–1.5 ng/mL, drawn 8–12 h post-dose, ~5–7 days after starting / changing dose
• Serum potassium (hypokalaemia potentiates toxicity)
• Renal function
• ECG for new arrhythmias; appetite (anorexia = early toxicity)

Toxicity and overdose

Plumb's p.402: in dogs the acute toxic dose after IV administration is reported as 0.177 mg/kg. Treatment of CHRONIC toxicity is dictated by severity — many patients do well simply by temporarily stopping the drug and re-evaluating the dose regimen. For a recent acute ingestion with no cardiotoxic or neurologic signs yet (coma, seizures), empty the stomach and give activated charcoal; because digoxin is slowly absorbed and undergoes ENTEROHEPATIC RECIRCULATION, repeated charcoal doses are indicated. Correct hypokalaemia, which both provokes and worsens toxicity. Note for ECG interpretation: digoxin itself causes PR prolongation and ST-segment depression, and produces false-positive ST-T changes — do not read these as new ischaemia.

Clinical pearls

• Anorexia / vomiting in a digitalised patient is toxicity until proven otherwise — stop the drug and check a level + potassium
• Correct hypokalaemia first — low potassium dramatically increases digoxin toxicity
• Skip loading doses; reaching steady state with maintenance dosing avoids most toxicity

Mechanism of action

Plumb's pp.400–401: cardiac (digitalis) glycoside. Inhibits the sarcolemmal Na+/K+-ATPase, raising intracellular sodium and, via Na+/Ca2+ exchange, intracellular calcium — the basis of the positive inotropy. In a failing heart the net effects are increased myocardial contractility with increased cardiac output; increased diuresis with reduction of oedema secondary to decreased sympathetic tone; reduction in heart size, heart rate, blood volume and pulmonary and venous pressures; and usually NO net change in myocardial oxygen demand. It also has direct and vagally-mediated electrophysiological effects that slow AV conduction — which is why its clearest modern indication is rate control in atrial fibrillation rather than inotropic support. Plumb's is explicit that many cardiologists no longer consider digoxin first-line for heart failure, particularly since pimobendan became available, and that digoxin alone is rarely if ever used for heart failure.

Formulations and products

• Digoxin 0.0625 mg tablet
• Digoxin 0.25 mg tablet
• Digoxin 0.05 mg/mL elixir

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other cardiovascular drugs

• Atenolol
• Benazepril
• Captopril
• Carvedilol
• Diltiazem
• Dobutamine
• Dopamine
• Enalapril

Frequently asked questions