SOTALOL

SOTALOL
(so-ta'lol)
Betapace, Betapace AF
Classifications: beta-adrenergic antagonist; antiarrhythmic class ii and iii;
Therapeutic: antiarrhythmic class ii and iii
Prototype: Amiodarone
Pregnancy Category: B

Availability

Betapace: 80 mg, 120 mg, 160 mg, 240 mg tablets

Betapace AF: 80 mg, 120 mg, 160 mg tablets

Action

Has both class II and class III antiarrhythmic properties. Slows heart rate, decreases AV nodal conduction, and increases AV nodal refractoriness. Produces significant reduction in both systolic and diastolic blood pressure.

Therapeutic Effect

Antiarrhythmic properties are effective in controlling ventricular arrhythmias as well as atrial fibrillation/flutter. Regulates blood pressure values.

Uses

Treatment of life-threatening ventricular arrhythmias (sustained ventricular tachycardia) and maintenance of normal sinus rhythm in patients with atrial fibrillation/flutter.

Unlabeled Uses

Hypertension, angina.

Contraindications

Hypersensitivity to sotalol; bronchial asthma, acute bronchospasm; sinus bradycardia, sick sinus syndrome; second and third degree heart block, long QT syndrome, cardiogenic shock, uncontrolled CHF; chronic bronchitis, emphysema; hypokalemia <4 mEq/L; creatinine clearance of <40 mL/min.

Cautious Use

CHF, electrolyte disturbances, recent MI, diabetes, sick sinus rhythm, renal impairment; pregnancy (category B); concomitant use of drugs which prolong the QT segment, and antiarrhythmic drugs; excessive diarrhea, or profuse sweating.

Route & Dosage

Ventricular Arrhythmias (Betapace)
Adult: PO Initial dose of 80 mg b.i.d. or 160 mg q.d. taken prior to meals, may increase every 3–4 d in 40–160 mg increments (most patients respond to 240–320 mg/d in 2 or 3 divided doses, doses >640 mg/d have not been studied)

Renal Impairment
Cl_cr >60 mL/min: q12h; 30–60 mL/min: q24h; 10–30 mL/min: q36–48h; <10 mL/min: Individualize carefully

Atrial Fibrillation/Flutter (Betapace AF)
Adult: PO Initial dose of 80 mg b.i.d., may increase every 3–4 d (max: 240 mg/d in 1–2 divided doses)

Renal Impairment
Cl_cr >60 mL/min: q12h; 40–60 mL/min: q24h; <40 mL/min contraindicated

Administration

Oral

Give on an empty stomach 1 h before or 2 h after meals. Do not give with milk or milk products.
Initiate and increase doses only under close supervision, preferably in a hospital with cardiac rhythm monitoring and frequent assessment.
Use smallest effective dose for patients with nonallergic bronchospasms.
Do not discontinue drug abruptly. Gradually reduce dose over 1–2 wk.
Store at room temperature, 15°–30° C (59°–86° F).

Adverse Effects (≥1%)

CV: AV block, hypotension, aggravation of CHF, although the incidence of heart failure may be lower than for other beta-blockers, life-threatening ventricular arrhythmias, including polymorphous ventricular tachycardia or torsades de pointes, bradycardia, dyspnea, chest pain, palpitation, bleeding (<2%). CNS: Headache, fatigue, dizziness, weakness, lethargy, depression, lassitude. GI: Nausea, vomiting, diarrhea, dyspepsia, dry mouth. Urogenital: Impotence, decreased libido. Metabolic: Hyperglycemia. Special Senses: Visual disturbances. Respiratory: Respiratory complaints. Skin: Rash.

Interactions

Drug: Antagonizes the effects of beta agonists. Amiodarone may lead to symptomatic bradycardia and sinus arrest. The hypoglycemic effects of oral hypoglycemic agents may be potentiated. May cause resistance to epinephrine in anaphylactic reactions. Should be used with caution with other antiarrhythmic agents. Food: Absorption may be reduced by food, especially milk and milk products.

Pharmacokinetics

Absorption: Slowly and completely from GI tract. Negligible first-pass metabolism. Reduced by food, especially milk and milk products. Peak: 2–3 h. Duration: 24 h. Distribution: Drug is hydrophilic and will enter the CSF slowly (about 10%). Crosses placental barrier. Distributed in breast milk. Not appreciably protein bound. Metabolism: Does not undergo significant hepatic enzyme metabolism and no active metabolites have been identified. Elimination: In urine with 75% of the drug excreted unchanged within 72 h. Half-Life: 7–18 h.

Nursing Implications

Assessment & Drug Effects

Monitor ECG for initial baseline and periodically thereafter (especially when doses are increased) because proarrhythmic events most often occur within 7 d of initiating therapy or increasing dose.
Lab test: Baseline serum electrolytes. Correct electrolyte imbalances of hypokalemia or hypomagnesemia prior to initiating therapy.
Monitor cardiac status carefully, including ECG, throughout therapy. Exercise special caution when sotalol is used concurrently with other antiarrhythmics, digoxin, or calcium channel blockers.
Monitor patients with bronchospastic disease (e.g., bronchitis, emphysema) carefully for inhibition of bronchodilation.
Monitor diabetics for loss of glycemic control. Beta blockage reduces the release of endogenous insulin in response to hyperglycemia and may blunt symptoms of acute hypoglycemia (e.g., tachycardia, BP changes).

Patient & Family Education

Be aware of risk for hypotension and syncope, especially with concurrent treatment with catecholamine-depleting drugs (e.g., reserpine, guanethidine).
Take radial pulse daily and report marked bradycardia (pulse below 60 or other established parameter) to physician.
Type 2 diabetics are at increased risk for hyperglycemia. All diabetics are at risk of possible masking of symptoms of hypoglycemia.
Do not abruptly discontinue drug because of the risk of exacerbation of angina, arrhythmias, and possible myocardial infarction.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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