Sotalol: veterinary dose and monograph

At a glance

Drug class

Cardiovascular

Also known as

Sotalol hydrochloride, Sotagard, Betapace

Species with doses

Dogs, Cats, Horses and Rabbits

General dose range

1–2 mg/kg PO q12h — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Ventricular tachyarrhythmias / frequent ventricular premature complexes
• Boxer ARVC and other cardiomyopathy-associated ventricular ectopy
• Selected supraventricular tachyarrhythmias
• Rate/rhythm control where combined beta- and class-III action is desired

Sotalol 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

• Ventricular tachyarrhythmia / ARVC: Papich 5e: 2 mg/kg q12h PO (medium/large dogs start 40 mg per dog q12h, increasing to 80 mg). Plumb’s p.1070: 1–2 mg/kg q12h (Fox; Moise; Atkins); 1–3 mg/kg twice daily (Henik); Boxers 1.5–3 mg/kg twice daily with mexiletine, or 40–80 mg per dog q12h. Titrate by Holter/ECG; do not stop abruptly.

Cats

• Ventricular/supraventricular arrhythmia: Papich 5e: 1–2 mg/kg q12h PO (10–20 mg per cat q12h). Plumb’s p.1070: 2 mg/kg PO twice daily (Atkins; Cote) — about ⅛ of an 80 mg tablet. Monitor for bradycardia and CHF.

Horses

• Atrial fibrillation / ventricular tachycardia: Papich 5e: atrial fibrillation 2 mg/kg PO q12h for 3 days; ventricular tachycardia 1 mg/kg PO q12h, increasing to 2–3 mg/kg q12h as needed.

Rabbits

• Atrial / ventricular arrhythmia: Carpenter's 6th ed (Rabbit cardiovascular table): 1.7 mg/kg PO q12h for both atrial and ventricular arrhythmias.

Contraindications

Significant bradyarrhythmia / high-grade AV block (without pacing), decompensated congestive heart failure, severe hypotension, bronchospastic disease (non-selective beta-blockade), and pre-existing marked QT prolongation. Hypokalaemia/hypomagnesaemia (proarrhythmia). Use caution with other QT-prolonging or negative-inotropic drugs. Known hypersensitivity.

Species-specific warnings

Cats: Monitor closely for bradycardia, hypotension and precipitation of CHF; dose conservatively (often per-cat) with ECG guidance.

Adverse effects

• Negative inotropy — can worsen/precipitate heart failure
• Bradycardia, hypotension, lethargy/weakness
• Proarrhythmia (QT prolongation, torsades-type rhythms) — especially with electrolyte derangement
• GI upset
• Bronchoconstriction (non-selective beta-blockade)

Drug interactions

• Other QT-prolonging drugs (some antiarrhythmics, macrolides, fluoroquinolones): additive torsades risk
• Other negative chronotropes/inotropes (diltiazem, digoxin, beta-blockers): additive bradycardia/AV block/myocardial depression
• Drugs causing hypokalaemia (loop/thiazide diuretics): increased proarrhythmia — keep potassium/magnesium normal
• Antacids: reduce absorption (separate dosing)

Pregnancy and lactation

Limited veterinary data; beta-blockers can cause fetal bradycardia/growth effects — use only if the arrhythmia risk to the dam outweighs this.

Monitoring

• ECG / Holter for efficacy AND QT interval (proarrhythmia)
• Heart rate, rhythm and blood pressure
• Serum potassium and magnesium (keep normal)
• Signs of worsening CHF (resting respiratory rate, effort)
• Never discontinue abruptly — taper to avoid rebound arrhythmia

Toxicity and overdose

Overdose: profound bradycardia, hypotension, AV block, heart failure, bronchospasm and, paradoxically, life-threatening ventricular proarrhythmia (torsades de pointes) from excessive QT prolongation — markedly worsened by hypokalaemia/hypomagnesaemia.

Management: No single antidote. For bradycardia/hypotension: atropine, IV fluids, and beta-agonist support (high-dose); glucagon is useful for beta-blocker overdose. Correct potassium/magnesium and treat torsades with IV magnesium sulphate ± overdrive pacing/isoproterenol. Continuous ECG; supportive intensive care.

Clinical pearls

• The dual beta-blocker + class-III action makes it a go-to for canine ventricular arrhythmias and Boxer ARVC
• Always normalise potassium and magnesium before/while dosing — hypokalaemia turns sotalol proarrhythmic
• Titrate with ECG/Holter; watch the QT interval, not just ectopy suppression
• Negative inotrope — use carefully in (or avoid in) decompensated heart failure
• Taper rather than stop suddenly to prevent rebound tachyarrhythmia

Mechanism of action

Two antiarrhythmic mechanisms in one molecule: (1) non-selective beta-adrenergic blockade (class II) slows sinus rate, AV conduction and sympathetic-driven arrhythmias; (2) class III action blocks the delayed-rectifier potassium current (IKr), prolonging action-potential duration and the effective refractory period, which suppresses re-entrant ventricular arrhythmias. The same QT prolongation underlies its proarrhythmic potential.

Formulations and products

• 40 mg tablet
• 80 mg tablet
• 160 mg tablet
• Sotagard — 40 / 80 mg tablet, Tablet (human-label)
• Sotalol — 40 / 80 mg tablet, Tablet (human-label)

Storage

Tablets: 15–30 °C, dry, protected from light.

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

• Quinidine
• Ramipril
• Sildenafil
• Sodium Nitroprusside
• Telmisartan
• Vasopressin (Arginine Vasopressin)

Frequently asked questions