CHF and arrhythmias:
Indications for: BETAPACE AF
Documented life-threatening ventricular arrhythmias. Maintenance of normal sinus rhythm in patients with highly symptomatic atrial fibrillation/atrial flutter (AFIB/AFL) who are currently in sinus rhythm.
Limitations of Use:
Not been shown to enhance survival in patients with life-threatening ventricular arrhythmias. Reserve its use for those in whom AFIB/AFL is highly symptomatic. Patients with paroxysmal AFIB that is easily reversed (eg, by Valsalva maneuver) should usually not be given Betapace/Betapace AF.
Initiate and titrate up in a hospital setting that can provide continuous ECG, creatinine clearance monitoring, and cardiac resuscitation. Initially 80mg twice daily. Increase at 3-day intervals in increments of 80mg/day provided the QTc <500msec. Ventricular arrhythmias (usual maintenance): 160–320mg/day divided in 2 or 3 doses (refractory patients may need 480–640mg/day). AFIB/AFL (usual maintenance): 120mg twice daily. Both: renal impairment (CrCl <60mL/min): prolong dosing interval (see full labeling).
<2yrs: see full labeling. ≥2yrs: initially 1.2mg/kg three times daily (3.6mg/kg/day). Titrate up to max 2.4mg/kg three times daily. Adjust dose based on clinical response, heart rate, and QTc.
BETAPACE AF Contraindications:
Sinus bradycardia. Sick sinus syndrome. 2nd or 3rd degree AV block, unless paced. Long QT syndromes. Cardiogenic shock. Decompensated heart failure. Serum potassium (<4mEq/L). Bronchial asthma or related bronchospastic conditions. Also for AFIB/AFL: baseline QT interval >450msec.
BETAPACE AF Warnings/Precautions:
Increased arrhythmia risk in females, renal impairment, reduced heart rate, history of sustained ventricular tachycardia or heart failure, or with higher doses of sotalol. Correct electrolyte imbalances (esp. hypokalemia, hypomagnesemia) and withdraw other antiarrhythmics prior to initiation. If QTc interval ≥500msec; reduce dose, lengthen the dosing interval, or discontinue therapy. Monitor hemodynamics in those with marginal cardiac compensation. Discontinue if symptoms of heart failure occurs. Bronchospastic disease. Diabetes. Acid-base imbalance. Hyperthyroidism. History of anaphylaxis. Surgery. Avoid abrupt cessation (withdraw over 1–2 weeks if possible, monitor for angina and acute coronary ischemia). Neonates. Labor & delivery: monitor. Pregnancy. Nursing mothers: not recommended.
BETAPACE AF Classification:
Class II and III antiarrhythmic.
BETAPACE AF Interactions:
Concomitant Class IA antiarrhythmics (eg, disopyramide, quinidine, procainamide), Class III antiarrhythmics (eg, amiodarone), or other drugs that prolong QT interval: not recommended. Discontinue Class I and III antiarrhythmics for at least 3 half-lives prior to initiation. Increased risk of bradycardia or hypotension with negative chronotropes (eg, digitalis glycosides, diltiazem, verapamil, β-blockers). Hypotension, bradycardia with reserpine, guanethidine, other catecholamine-depleting drugs. Increased rebound hypertension when withdrawing clonidine. Diuretics (monitor electrolytes). Antagonizes β-agonists (eg, albuterol, terbutaline, isoproterenol). Monitor antidiabetic agents. May block epinephrine. Avoid within 2 hours of aluminum- or magnesium-containing antacids. May result in falsely elevated levels of urinary metanephrine when measured by fluorimetric or photometric methods.
Fatigue, bradycardia (<50bpm), dyspnea, proarrhythmia, asthenia, dizziness, headache, nausea, vomiting, diarrhea; hypotension, ventricular arrhythmias (eg, sustained VT/VF, torsade de pointes), QT prolongation.
Tabs—100; AF tabs—60