CHF and arrhythmias:
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.
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