Generic Name and Formulations:
Disopyramide (as phosphate) 100mg, 150mg; caps.
Indications for NORPACE:
Documented life-threatening ventricular arrhythmias.
400–800mg daily in 4 divided doses every 6hrs. For rapid control of ventricular arrhythmias, consider loading dose of 300mg (200mg if body weight <110 lbs). Renal dysfunction, cardiac decompensation, or body wt <110 lbs: see full labeling.
Initiate in hospital. Give as divided doses every 6hrs: <1yr: 10–30mg/kg per day; 1–4yrs: 10–20mg/kg per day. 4–12yrs: 10–15mg/kg per day. 12–18yrs: 6–15mg/kg per day.
Cardiogenic shock. 2nd- or 3rd- degree AV block, unless paced. Congenital QT prolongation. Severe renal insufficiency (CrCl ≤40mL/min): CR form not recommended.
Excessive mortality or non-fatal cardiac arrest rate was seen in CAST trial. Correct potassium imbalance before starting. Discontinue if hypotension or CHF worsening occurs; if needed, restart at lower dose after cardiac compensation established. Reduce dose in 1st-degree AV block, consider discontinuing if persistent. Monitor closely or discontinue if QT prolongation or QRS widening occurs. Atrial tachyarrhythmias: digitalize first. Conduction defects. Cardiomyopathy. Renal or hepatic dysfunction. Urinary retention. BPH. Glaucoma. Myasthenia gravis. Chronic malnutrition. Elderly. Labor & delivery. Pregnancy (Cat.C): may stimulate uterine contractions. Nursing mothers: not recommended.
Class I antiarrhythmic.
Avoid other antiarrhythmics except in unresponsive, life-threatening arrhythmias. Avoid CYP3A4 inhibitors (eg, erythromycin, clarithromycin); may result in fatal interactions. Hypoglycemia with β-blockers, alcohol. Antagonized by hepatic enzyme inducers (eg, phenytoin). Do not give within 48hrs before or 24hrs after verapamil.
Anticholinergic effects (eg, dry mouth, urinary retention, constipation, blurred vision), GI upset, dizziness, fatigue, impotence, hypotension, heart failure, AV block, edema, rash, hypoglycemia, hypokalemia, jaundice, blood dyscrasias, lupus-like syndrome, psychosis.
Caps—100; CR—100, 500