Ibutilide fumarate
Ibutilide fumarate
Ibutilide fumarate
(ih- BYOU-tih-lyd)
Pregnancy Category: C Corvert (Rx)

Classification: Antiarrhythmic agent

Action/Kinetics: Class III antiarrhythmic agent. Delays repolarization by activation of a slow, inward current (mostly sodium), rather than by blocking outward potassium currents (the way other class III antiarrhythmics act). This results in prolongation in the duration of the atrial and ventricular action potential and refractoriness. Also a dose-related prolongation of the QT interval. High systemic plasma clearance that approximates liver blood flow; protein binding is less than 40%. t 1/2, terminal: 6 hr. Over 80% is excreted in the urine (with 7% excreted unchanged) and approximately 20% is excreted through the feces.

Uses: For rapid conversion of atrial fibrillation or atrial flutter of recent onset to sinus rhythm. Determination of clients to receive ibutilide should be based on expected benefits of maintaining sinus rhythm and whether this outweighs both the risks of the drug and of maintenance therapy.

Contraindications: Use of certain class Ia antiarrhythmic drugs (e.g., disopyramide, quinidine, procainamide) and certain class III drugs (e.g., amiodarone and sotalol) concomitantly with ibutilide or within 4 hr of postinfusion.

Special Concerns: May cause potentially fatal arrhythmias, especially sustained polymorphic ventricular tachycardia, usually in association with QT prolongation (torsades de pointes). Effectiveness has not been determined in clients with arrhythmias of more than 90 days in duration. Breast feeding should be discouraged during therapy. Safety and efficacy have not been determined in children less than 18 years of age.

Side Effects: CV: Life-threatening arrhythmias, either sustained or nonsustained polymorphic ventricular tachycardia (torsades de pointes). Induction or worsening of ventricular arrhythmias. Nonsustained monomorphic ventricular extrasystoles, nonsustained monomorphic ventricular tachycardia, sinus tachycardia, SVT, hypotension, postural hypotension, bundle branch block, AV block, bradycardia, QT-segment prolongation, hypertension, palpitation, supraventricular extrasystoles, nodal arrhythmia, CHF, idioventricular rhythm, sustained monomorphic VT. Miscellaneous: Headache, nausea, syncope, renal failure.

Overdose Management: Symptoms: Increased ventricular ectopy, monomorphic ventricular tachycardia, AV block, nonsustained polymorphic VT. Treatment: Treat symptoms.

Drug Interactions: Amiodarone / Risk of prolonged refractoriness Antidepressants, tricyclic and tetracyclic / Risk of proarrhythmias Digoxin / Supraventricular arrhythmias due to ibutilide, may mask cardiotoxicity R/T high digoxin levels Disopyramide / Risk of prolonged refractoriness Histamine H ₁ receptor antagonists / Risk of proarrhythmias Phenothiazines / Risk of proarrhythmias Procainamide / Risk of prolonged refractoriness Quinidine / Risk of prolonged refractoriness Sotalol / Risk of prolonged refractoriness

How Supplied: IV Solution: 0.1 mg/mL.

Dosage
?IV Infusion Atrial fibrillation or atrial flutter of recent onset.
Clients weighing 60 kg or more, initial: 1 mg (one vial) infused over 10 min. Clients weighing less than 60 kg, initial: 0.01 mg/kg infused over 10 min. If the arrhythmia does not terminate within 10 min after the end of the initial infusion (regardless of the body weight), a second 10-min infusion of equal strength may be given 10 min after completion of the first infusion.