Generic Name and Formulations:
Disopyramide (as phosphate) 100mg, 150mg; controlled-release caps.
Indications for NORPACE-CR:
Documented life-threatening ventricular arrhythmias.
200–400mg every 12hrs.
Use immediate-release caps.
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.
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.
Class I antiarrhythmic.
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