Sotalol

Sotalol In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Produces a prolongation of action potential duration and refractory period, via selective inhibition of potassium channels (Class III antiarrhythmic).
• Also has non-selective beta-adrenergic blocking effects, but considered a weak beta-blocker.

Uses of Sotalol

• Treatment of ventricular arrhythmias, less so supraventricular arrhythmia (most associated with accessory pathway).
• Used most commonly in dogs with ventricular arrhythmias secondary to myocardial disease.

Dose of Sotalol in Dogs and Cats

Dogs:

• 0.5–3 mg/kg p.o. q12h. Start with lower doses if myocardial function is reduced.
• Anecdotal doses starting at 0.5 mg/kg i.v. given over 2 min, up to 3 times (to a total dose of 1.5 mg/kg i.v.).

Cats:

• 10–20 mg/cat p.o. q12h.

Side Effects of Sotalol in Dogs and Cats

• Non-selective beta-blocking effects in dogs can reduce heart rate, stroke volume, and cardiac output, potentially leading to congestive heart failure.
• The drug is excreted through urine and feces, and its elimination half-life may extend with renal insufficiency, resulting in accumulation at standard doses.
• Adverse effects encompass hypotension, bradyarrhythmias, bronchospasm, depression, as well as nausea, vomiting, and diarrhea.
• The drug carries a proarrhythmic potential, and elevated doses can prolong the QT interval, heightening the risk of torsades de pointes, especially in the presence of hypokalemia.

Contraindications of Sotalol in Dogs and Cats

• Asthma, sinus bradycardia, AV block or decompensated CH, long QT on ECG.

Some Notes:

• Sympathomimetics such as terbutaline, phenylpropanolamine, and adrenaline may have their effects blocked by sotalol, potentially reducing its efficacy.
• Concurrent use of sotalol with other beta-blockers or myocardial depressant anesthetic agents can lead to additive myocardial depression.
• Hypotensive effects of sotalol may be enhanced when used alongside phenothiazines, furosemide, hydralazine, and other vasodilators.
• Sotalol may prolong the hypoglycemic effects of insulin therapy.
• Caution should be exercised when using negative inotropics (e.g., calcium-channel blockers) concurrently with sotalol, especially in patients with pre-existing systolic dysfunction or congestive heart failure (CHF).
• Beta-blocking activity of the drug is approximately one-third of that of propranolol.
• Efficacy assessment is preferably done through repeated Holter ECG monitoring.
• Successful combination use with mexilitine is possible for treating severe ventricular arrhythmia.
• Caution is advised when using the drug in patients with renal failure or medically controlled congestive heart failure (CHF).