Monograph Details

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Cardiovascular System > CHF and arrhythmias

NORPACE-CR

Manufacturer

Pfizer Labs

Legal Classification

Pharmacological Class

Class I antiarrhythmic.

Generic Name

Disopyramide (as phosphate) 100mg, 150mg; controlled-release caps.

Also

• NORPACE

Indications

Documented life-threatening ventricular arrhythmias.

Children

Use immediate-release caps.

Adults

200–400mg every 12 hours.

Contraindications

Cardiogenic shock. 2^nd- or 3^rd- degree AV block, unless paced. Congenital QT prolongation. Severe renal insufficiency (CrCl ≤40mL/min): CR form not recommended.

Precautions

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 1^st-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.

Interactions

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 48 hours before or 24 hours after verapamil.

Adverse Reactions

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.

How Supplied

Caps—100
CR—100, 500

Additional Resources

• Related Prescribing Note