Ibutilide Fumarate (2 brand names, 1 dosage form, 1 route)
Available dosage forms: INJECTABLE.
Routes of administration: INJECTION.
Brand Names
- CORVERT
- IBUTILIDE FUMARATE
Indications and Usage
Ibutilide fumarate injection is indicated for the rapid conversion of atrial fibrillation or atrial flutter of recent onset to sinus rhythm. Patients with atrial arrhythmias of longer duration are less likely to respond to ibutilide fumarate. The effectiveness of ibutilide has not been determined in patients with arrhythmias of more than 90 days in duration. LIFE-THREATENING ARRHYTHMIAS—APPROPRIATE TREATMENT ENVIRONMENT Ibutilide fumarate can cause potentially fatal arrhythmias, particularly sustained polymorphic ventricular tachycardia, usually in association with QT prolongation (torsades de pointes), but sometimes without documented QT prolongation. In registration studies, these arrhythmias, which require cardioversion, occurred in 1.7% of treated patients during, or within a number of hours of, use of Ibutilide fumarate. These arrhythmias can be reversed if treated promptly (see WARNINGS, Proarrhythmia). It is essential that Ibutilide fumarate be administered in a setting of continuous ECG monitoring and by personnel trained in identification and treatment of acute ventricular arrhythmias, particularly polymorphic ventricular tachycardia. Patients with atrial fibrillation of more than 2 to 3 days’ duration must be adequately anticoagulated, generally for at least 2 weeks. CHOICE OF PATIENTS Patients with chronic atrial fibrillation have a strong tendency to revert after conversion to sinus rhythm (see CLINICAL STUDIES) and treatments to maintain sinus rhythm carry risks. Patients to be treated with Ibutilide fumarate , therefore, should be carefully selected such that the expected benefits of maintaining sinus rhythm outweigh the immediate risks of Ibutilide fumarate , and the risks of maintenance therapy, and are likely to offer an advantage compared with alternative management.
Dosage and Administration
The recommended dose based on controlled trials (see CLINICAL STUDIES ) is outlined in the Table below. Ibutilide infusion should be stopped as soon as the presenting arrhythmia is terminated or in the event of sustained or nonsustained ventricular tachycardia, or marked prolongation of QT or QTc. Recommended Dose of Ibutilide Fumarate Injection Patient Weight Initial Infusion (over 10 minutes) Second Infusion 60 kg (132 lb) or more One vial (1 mg ibutilide fumarate) If the arrhythmia does not terminate within 10 minutes after the end of the initial infusion, a second 10-minute infusion of equal strength may be administered 10 minutes after completion of the first infusion. Less than 60 kg (132 lb) 0.1 mL/kg (0.01 mg/kg ibutilide fumarate) In a trial comparing ibutilide and sotalol (see CLINICAL STUDIES ), 2 mg ibutilide fumarate administered as a single infusion to patients weighing more than 60 kg was also effective in terminating atrial fibrillation or atrial flutter.In the post-cardiac surgery study (see CLINICAL STUDIES ), one or two intravenous infusions of 0.5 mg (0.005 mg/kg per dose for patients weighing less than 60 kg) was effective in terminating atrial fibrillation or atrial flutter.Patients should be observed with continuous ECG monitoring for at least 4 hours following infusion or until QTc has returned to baseline. Longer monitoring is required if any arrhythmic activity is noted. Skilled personnel and proper equipment (see WARNINGS, Proarrhythmia ), such as a cardioverter/defibrillator, and medication for treatment of sustained ventricular tachycardia, including polymorphic ventricular tachycardia, must be available during administration of ibutilide fumarate and subsequent monitoring of the patient.DilutionIbutilide fumarate injection may be administered undiluted or diluted in 50 mL of diluent. Ibutilide fumarate may be added to 0.9% Sodium Chloride Injection or 5% Dextrose Injection before infusion. The contents of one 10 mL vial (0.1 mg/mL) may
Contraindications
Ibutilide fumarate injection is contraindicated in patients who have previously demonstrated hypersensitivity to ibutilide fumarate or any of the other product components.
Adverse Reactions
Ibutilide fumarate injection was generally well tolerated in clinical trials. Of the 586 patients with atrial fibrillation or atrial flutter who received ibutilide fumarate in phase II/III studies, 149 (25%) reported medical events related to the cardiovascular system, including sustained polymorphic ventricular tachycardia (1.7%) and nonsustained polymorphic ventricular tachycardia (2.7%).Other clinically important adverse events with an uncertain relationship to ibutilide fumarate include the following (0.2% represents one patient): sustained monomorphic ventricular tachycardia (0.2%), nonsustained monomorphic ventricular tachycardia (4.9%), AV block (1.5%), bundle branch block (1.9%), ventricular extrasystoles (5.1%), supraventricular extrasystoles (0.9%), hypotension/postural hypotension (2%), bradycardia/sinus bradycardia (1.2%), nodal arrhythmia (0.7%), congestive heart failure (0.5%), tachycardia/sinus tachycardia/supraventricular tachycardia (2.7%), idioventricular rhythm (0.2%), syncope (0.3%), and renal failure (0.3%). The incidence of these events, except for syncope, was greater in the group treated with ibutilide fumarate than in the placebo group.Another adverse reaction that may be associated with the administration of ibutilide fumarate was nausea, which occurred with a frequency greater than 1% more in ibutilide-treated patients than those treated with placebo.The medical events reported for more than 1% of the placebo- and ibutilide-treated patients are shown in the following Table. Treatment-Emergent Medical Events With Frequency of More Than 1% and Higher Than That of Placebo Event PlaceboN=127 All IbutilideN=586 Patients Patients n % n % CARDIOVASCULAR Ventricular extrasystoles 1 0.8 30 5.1 Nonsustained monomorphic VT 1 0.8 29 4.9 Nonsustained polymorphic VT — — 16 2.7 Hypotension 2 1.6 12 2.0 Bundle branch block — — 11 1.9 Sustained polymorphic VT — — 10 1.7 AV block 1 0.8 9 1.5 Hypertension — — 7 1.2 QT segment prolonged — — 7 1.2 Bradycardia
Drug Interactions
No specific pharmacokinetic or other formal drug interaction studies were conducted. DigoxinSupraventricular arrhythmias may mask the cardiotoxicity associated with excessive digoxin levels. Therefore, it is advisable to be particularly cautious in patients whose plasma digoxin levels are above or suspected to be above the usual therapeutic range. Co-administration of digoxin did not have effects on either the safety or efficacy of ibutilide in the clinical trials.Calcium channel blocking agentsCo-administration of calcium channel blockers did not have any effect on either the safety or efficacy of ibutilide in the clinical trials.Beta-adrenergic blocking agentsCo-administration of beta-adrenergic blocking agents did not have any effect on either the safety or efficacy of ibutilide in the clinical trials.
Overdosage
Acute Experience in Animals Acute overdose in animals results in CNS toxicity; notably, CNS depression, rapid gasping breathing, and convulsions. The intravenous median lethal dose in the rat was more than 50 mg/kg which is, on a mg/m2 basis, at least 250 times the maximum recommended human dose. Human Experience In the registration trials with ibutilide fumarate injection, four patients were unintentionally overdosed. The largest dose was 3.4 mg administered over 15 minutes. One patient (0.025 mg/kg) developed increased ventricular ectopy and monomorphic ventricular tachycardia, another patient (0.032 mg/kg) developed AV block—3rd degree and nonsustained polymorphic VT, and two patients (0.038 and 0.020 mg/kg) had no medical event reports. Based on known pharmacology, the clinical effects of an overdosage with ibutilide could exaggerate the expected prolongation of repolarization seen at usual clinical doses. Medical events (eg, proarrhythmia, AV block) that occur after the overdosage should be treated with measures appropriate for that condition.