Digoxin
Digoxin is used in veterinary medicine for ventricular rate control in supraventricular arrhythmias.
Group
Cardiac glycoside
Mechanism of Action
Inhibits Na+/K+-ATPase and increases vagal effects on AV conduction.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Cardiac rate control | 0.005–0.011 mg/kg | PO | Every 12 h | Lean body weight; elixir may require a 10% lower amount. |
| Cardiac rate control | 0.005–0.01 mg/kg | PO | Every 12 h | Alternative regimen specifically for dogs under 20 kg. |
| Large-dog cardiac rate control | Reference only | PO | Dogs over 20 kg: 0.22 mg/m² every 12 hours; reduce 10% for elixir. BSA calculation required. | |
| Rapid digitalization — Loading | 0.0055–0.011 mg/kg | IV | Every 1 h | Titrate to effect under ECG and concentration monitoring. |
| Atrial fibrillation | 0.005 mg/kg | PO | Every 12 h | May be combined with diltiazem 3 mg/kg every 12 hours. |
| Atrial fibrillation with heart failure | 0.005–0.0075 mg/kg | PO | Every 12 h | Normal renal function; target trough 0.8–1.2 ng/mL. |
| Dilated cardiomyopathy with atrial fibrillation | 0.0025 mg/kg | PO | Every 12 h | Loading usually omitted; extra caution with ventricular arrhythmias. Target trough 0.8–1.2 ng/mL. |
| Atrial fibrillation | 0.003–0.005 mg/kg | PO | Every 12 h |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Cardiac rate control | 0.008–0.01 mg/kg | PO | Every 48 h |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Cardiac support — Loading | 22 mcg/kg | IV | ||
| Cardiac support — Maintenance | 0.86 mcg/kg/hour | IV | Continuous | |
| Cardiac support — Maintenance | 3.4 mcg/kg | IV | Every 4 h | Intermittent alternative to continuous infusion. |
Horse
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Cardiac support | 2 mcg/kg | IV | Every 12 h | |
| Cardiac support | 15 mcg/kg | PO | Every 12 h |
Ferret
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dilated cardiomyopathy — Initial | 0.01 mg/kg | PO | Every 24 h | Oral liquid; increase to twice daily only after response assessment. |
| Heart failure — Maintenance | 0.005–0.01 mg/kg | PO | Every 12–24 h | Monitor serum digoxin and potassium. |
Hamster
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dilated cardiomyopathy | 0.05–0.1 mg/kg | PO | Every 12 h |
Indications
- Ventricular rate control in supraventricular arrhythmias
- Adjunctive heart failure treatment
Contraindications
- Narrow therapeutic index; heightened sensitivity in cats and some Dobermans.
Interactions
- Hypokalemia increases toxicity.
- Quinidine, macrolides and other inhibitors can raise exposure.
- Beta blockers and calcium-channel blockers increase AV-block risk.
- Phenobarbital may lower exposure.
Adverse effects
- Arrhythmias and AV block
- Vomiting, anorexia and diarrhea
Toxicity
Gastrointestinal signs may precede serious arrhythmias; stop treatment and assess concentration, potassium and cardiac rhythm.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Digoxin 0.0625 mg | Tablet | 0.0625 mg / tablet | PO |
| Digoxin 0.125 mg | Tablet | 0.125 mg / tablet | PO |
| Digoxin 0.25 mg | Tablet | 0.25 mg / tablet | PO |
| Digoxin elixir 0.05 mg/mL | Oral Liquid | 0.05 mg / mL | PO |
| Digoxin elixir 0.15 mg/mL | Oral Liquid | 0.15 mg / mL | PO |
Monitoring and Administration
Calculate using lean body weight. Elixir doses may need a 10% reduction compared with tablets.
Monitor ECG, renal function, electrolytes and serum concentration 8–10 hours after dosing; a commonly used target is 0.8–1.5 ng/mL.
Avoid mixing tablets with other medicines when compounding and avoid very acidic solutions.
The additional avian regimen omits its route and ranges from 0.02–0.5 mg/kg every 12 hours initially, then 0.01 mg/kg every 12–24 hours. This very wide, incompletely specified regimen is not a calculable prescription.