Sotalol
d,l-sotalol hydrochloride
Also known as: Betapace · Sotacor · MJ-1999 · d,l-sotalol hydrochloride · sotaloli hydrochloridum · Sotalolum
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 |
|---|---|---|---|---|---|
| General antiarrhythmic | 1-2 mg/kg | PO | q12h | — | 🌎 NA |
| General antiarrhythmic | 1-3 mg/kg | PO | twice daily | — | 🌎 NA |
| For ventricular tachycardia | 1-2 mg/kg | PO | twice daily | — | 🌎 NA |
| For ventricular tachyarrhythmias in Boxers in combination with mexiletine | 1.5-3 mg/kg | PO | twice daily | — | 🌎 NA |
| In Boxers | 40-80 mg (total dose) | PO | q12h | — | 🌎 NA |
| Ventricular arrhythmias | 0.5-3 mg/kg | PO | q12h | Ongoing | 🌍 EU |
| Ventricular arrhythmias (Acute/Severe) | 0.5 mg/kg given over 2 min, up to 3 times (to a total dose of 1.5 mg/kg) | IV | As needed | Acute setting | 🌍 EU |
- For ventricular tachyarrhythmias in Boxers in combination with mexiletine: Given with mexiletine (5-7.5 mg/kg PO three times daily)
- Ventricular arrhythmias: Start with lower doses if myocardial function is reduced.
- Ventricular arrhythmias (Acute/Severe): Anecdotal dosing.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| General antiarrhythmic | 2 mg/kg | PO | twice daily | — | 🌎 NA |
| For ventricular tachyarrhythmias | 2 mg/kg | PO | q12h | — | 🌎 NA |
| General antiarrhythmic | 1-2 mg/kg | PO | q12h | — | 🌎 NA |
| General antiarrhythmic | 1/8th of an 80 mg tablet (approximately 2 mg/kg) | PO | twice daily | — | 🌎 NA |
| Ventricular arrhythmias | 10-20 mg/cat | PO | q12h | Ongoing | 🌍 EU |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Sotalol is a unique antiarrhythmic agent that possesses both non-selective beta-blocking (Class II) and potassium channel blocking (Class III) properties.
- Clinical Utility: It is primarily used in veterinary medicine to treat ventricular tachycardias and occasionally supraventricular tachycardias in dogs and cats.
- Target Populations: It is highly favored for managing ventricular arrhythmias in Boxer dogs (often associated with Arrhythmogenic Right Ventricular Cardiomyopathy - ARVC) and in cases that are refractory to lidocaine.
- Pharmacological Pearl: Sotalol is a racemic mixture. Both the d- and l- isomers exhibit Class III antiarrhythmic activity, but only the l- isomer possesses beta-blocking activity. Its beta-blocking potency is approximately 30% that of propranolol.
Mechanism of action
Sotalol exerts a dual mechanism of action:
- Class II (Beta-Blocking) Action: Competitively antagonizes non-selective $\beta_1$ and $\beta_2$ adrenergic receptors $\rightarrow$ decreases heart rate, slows AV nodal conduction, and exerts a negative inotropic effect on the myocardium.
- Class III (Antiarrhythmic) Action: Selectively inhibits the rapid delayed rectifier potassium current ($I_{Kr}$) $\rightarrow$ prolongs the action potential duration (APD) and the effective refractory period (ERP) in both atrial and ventricular myocardium without affecting depolarization or conduction velocity.
Safety & warnings
Contraindications
- Asthma or reactive airway disease
- Sinus bradycardia
- 2nd or 3rd degree AV block (unless artificially paced)
- Long QT syndromes
- Cardiogenic shock
- Uncontrolled congestive heart failure (CHF)
- Atrioventricular (AV) block
- Decompensated congestive heart failure (CHF)
- Long QT interval on ECG
Adverse effects
- Negative inotropism (decreased heart contractility)
- Proarrhythmia (can induce new or worsen existing arrhythmias)
- Dyspnea / Bronchospasm
- Fatigue / Lethargy
- Dizziness / Syncope exacerbation
- Nausea / Vomiting
- Bradycardia
- Hypotension
- Bradyarrhythmias
- Depression
- Diarrhoea
- Decreased cardiac output
- Precipitation of congestive heart failure
- Prolonged QT interval
- Torsades de pointes (proarrhythmic effect)
Precautions
Use with caution in patients with congestive heart failure (due to negative inotropic effects), diabetes mellitus, or hyperthyroidism (may mask clinical signs of hypoglycemia or thyrotoxicosis). Use with caution in patients with renal dysfunction; dosage intervals may need to be extended as it is renally excreted. Safety in pregnancy is not fully established (FDA Category B). Sotalol enters maternal milk at up to 5x serum concentrations; consider milk replacer for nursing animals.
Drug interactions
May prolong refractory periods; concurrent use not recommended.
Additive myocardial depression may occur.
May reduce oral sotalol absorption; separate doses by at least 2 hours.
May prolong refractory periods and QT interval; concurrent use not recommended.
May prolong QT interval.
Potential to increase hypotensive effects; additive effects on AV conduction or ventricular function. Use with caution.
May prolong QT interval.
Increased risk for rebound hypertension if clonidine is discontinued after concomitant therapy.
Potential for increased risks for proarrhythmic events.
May prolong QT interval.
Clearance of lidocaine may be impaired by sotalol.
May prolong QT interval.
May have additive hypotensive and bradycardic effects.
Actions may be blocked by sotalol.
May prolong QT interval.
Mutual antagonism; sotalol may block their actions, and they may reduce sotalol's efficacy.
Additive myocardial depression.
Additive myocardial depression.
Enhanced hypotensive effects; risk of hypokalaemia which increases risk of torsades de pointes.
Enhanced hypotensive effects.
May prolong hypoglycaemic effects of insulin therapy.
Additive negative inotropic effects; use with extreme caution in patients with systolic dysfunction or CHF.
Monitoring
- Efficacy via Electrocardiogram (ECG)
- Adverse effects (heart rate, blood pressure, respiratory effort)
- Renal function (baseline and periodic, as drug is renally excreted)
- Blood glucose (especially in diabetic patients)
- Heart rate and rhythm (Holter ECG monitoring is highly recommended to assess efficacy and detect proarrhythmias)
- Renal function (BUN, Creatinine, SDMA)
- Serum electrolytes (especially potassium, to avoid hypokalaemia)
- Clinical signs of congestive heart failure
Pharmacokinetics
Half-life
Absorption
Bioavailability is 90-100% if given on an empty stomach. Food may reduce bioavailability by approximately 20%. Unlike propranolol, sotalol does not have any appreciable first-pass effect.
Distribution
Relatively low lipid solubility and virtually no protein binding. Enters maternal milk in concentrations up to 5 times that found in serum.
Metabolism
Minimal to no hepatic metabolism.
Elimination
Elimination is almost entirely via the kidneys, and most of the drug is excreted unchanged.
Overdose
Overdoses may result in bradycardia, hypotension, congestive heart failure, bronchospasm, and hypoglycemia.
- Treatment: Use gut evacuation (emesis or gastric lavage) if not contraindicated and when there is a significant risk of morbidity.
- Supportive Care: Treat adverse effects symptomatically and supportively (e.g., atropine for bradycardia, fluids/vasopressors for hypotension, bronchodilators for bronchospasm).
Available products
Formulations
- Tablets
- Injection solution concentrate
- 40 mg oral tablet
- 80 mg oral tablet
- 160 mg oral tablet
- 200 mg oral tablet
- 10 mg/ml injectable solution
- 10 mg oral tablet (special reformulation)
- 30 mg oral tablet (special reformulation)
Human-labeled
- Sotalol HCl Tablets: 80 mg, 120 mg, 160 mg & 240 mg; Betapace® (Bayer); generic
- Sotalol Injection Solution Concentrate: 15 mg/mL in 10 mL vials; generic
- Sotacor tablets
- Sotalol generic tablets (40 mg, 80 mg, 160 mg, 200 mg)
- Sotalol generic injection (10 mg/ml)
Regulatory status
Human registered products used under the cascade.
POM (Prescription Only Medicine). Human registered products used under the cascade.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets at room temperature.
Client information
Important: Do not stop this medication suddenly or alter the dose without consulting your veterinarian. Abrupt withdrawal can cause dangerous rebound arrhythmias or high blood pressure.
- Administration: For best absorption, give on an empty stomach if your pet tolerates it. If stomach upset occurs, you may give it with a small amount of food.
- Monitoring: Watch your pet closely for signs of extreme fatigue, weakness, fainting (syncope), or difficulty breathing.
- Communication: Report any vomiting, lethargy, or breathing issues to your veterinarian immediately. Keep all follow-up appointments for ECG monitoring to ensure the drug is working safely.
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.