Pharmacologic class: Beta-adrenergic blocker (nonselective)
Therapeutic class: Antiarrhythmic (classes II and III)
Pregnancy risk category B
FDA Box Warning
• To minimize risk of induced arrhythmia, patients starting or restarting drug should be placed for at least 3 days (on maintenance dosage) in facility that can provide cardiac resuscitation, continuous ECG monitoring, and creatinine clearance calculations.
• Drug also is indicated to treat documented life-threatening ventricular arrhythmias and marketed as Betapace. However, don't substitute Betapace for Betapace AF because of significant labeling differences.
Blocks stimulation of cardiac beta1-adrenergic and pulmonary, vascular, and uterine beta2-adrenergic receptor sites. This action reduces cardiac output and blood pressure, depresses sinus heart rate, and prolongs refractory period in atria and ventricles.
Tablets: 80 mg, 120 mg, 160 mg, 240 mg
Tablets (Betapace AF): 80 mg, 120 mg, 160 mg
Indications and dosages
➣ Ventricular arrhythmias
Adults: 80 mg P.O. b.i.d. (Betapace); may increase dosage gradually. For maintenance, 160 to 320 mg/day in two to three divided doses; some patients may require 240 to 320 mg/day in divided doses. For refractory ventricular fibrillation, may increase to 480 to 640 mg/day in divided doses.
➣ Atrial fibrillation or atrial flutter
Adults: 80 mg P.O. b.i.d. (Betapace AF). With careful monitoring, may increase to 120 mg b.i.d. p.r.n., to a maximum of 160 P.O. b.i.d.
• Renal impairment
• Hypersensitivity to drug
• Uncontrolled heart failure
• Bronchial asthma, chronic obstructive pulmonary disease
• Congenital or acquired long-QT syndrome
• Sinus bradycardia, second- or third-degree atrioventricular (AV) block (unless patient has pacemaker)
• Sick sinus syndrome
• Cardiogenic shock
• Creatinine clearance below 40 ml/minute
Use cautiously in:
• renal or hepatic impairment, diabetes mellitus, hyperthyroidism, patients undergoing major surgery
• history of severe allergic reactions
• elderly patients
• pregnant or breastfeeding patients
• children (safety not established).
• Give 1 hour before or 2 hours after meals or antacids.
• Keep in mind that Betapace and Betapace AF have different indications and are not interchangeable or therapeutically equivalent.
CNS: fatigue, weakness, anxiety, dizziness, drowsiness, insomnia, memory loss, depression, mental status changes, nervousness, paresthesia, nightmares
CV: orthostatic hypotension, peripheral vasoconstriction, bradycardia, arrhythmias, heart failure, AV block
EENT: blurred vision, dry eyes, nasal stuffiness
GI: nausea, constipation, diarrhea
GU: erectile dysfunction, decreased libido
Metabolic: hyperglycemia, hypoglycemia
Musculoskeletal: joint pain, back pain, muscle cramps
Respiratory: wheezing, bronchospasm
Skin: itching, rash
Other: lupus syndrome, hypersensitivity reaction
Drug-drug. Amphetamines, ephedrine, epinephrine, norepinephrine, phenylephrine, pseudoephedrine: unopposed alpha-adrenergic stimulation, causing excessive hypotension and bradycardia
Beta-adrenergic bronchodilators, theophylline: decreased efficacy of these drugs
Calcium channel blockers: increased risk of adverse cardiovascular reactions
Class IA antiarrhythmics (such as amiodarone, quinidine): increased risk of arrhythmias
Clonidine: excessive rebound hypertension with clonidine withdrawal
Ergot alkaloids: peripheral ischemia or gangrene
General anesthestics, phenytoin (I.V.), verapamil: additive myocardial depression
Lidocaine: increased lidocaine blood level, resulting in toxicity
Sulfonylureas: increased hypoglycemic effect
Drug-diagnostic tests. Antinuclear antibody: increased titers
Blood urea nitrogen, glucose, lipoproteins, potassium, triglycerides, uric acid: increased levels
Drug-food. Any food: decreased drug absorption
• Monitor ECG, electrolyte levels, and vital signs closely for first 3 days of therapy.
• Assess patient closely for signs and symptoms of heart failure.
• In long-term use, watch for signs and symptoms of drug-induced lupus syndrome.
• Tell patient drug may cause significant cardiac effects. Explain need for ECG monitoring during first few days of therapy.
☞ Teach patient to recognize and immediately report signs and symptoms of heart failure and electrolyte imbalances.
• Inform patient that drug can cause serious interactions with many common drugs. Instruct him to tell all prescribers he's taking it.
☞ Teach patient to recognize and promptly report signs and symptoms of drug-induced lupus syndrome.
• Advise patient that drug may cause CNS effects that increase his injury risk. Encourage him to use appropriate safety precautions.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.