Pronunciation: ih-BYOO-tih-lide FEW-muh-rate
Class: Antiarrhythmic agent
- Solution 0.1 mg/mL
Prolongs atrial and ventricular action potential duration and refractoriness by activation of a slow inward current (predominantly sodium).
Vd at steady state is approximately 11 L/kg. Approximately 40% is protein bound.
8 metabolites are formed via oxidation. Only the ω-hydroxy metabolite possesses activity similar to ibutilide.
Cl is 29 mL/min/kg. Approximately 82% is excreted in the urine (7% unchanged) and approximately 19% in feces. The mean t ½ is approximately 6 h (range is 2 to 12 h).
Indications and Usage
Rapid conversion of recent onset atrial fibrillation or atrial flutter to sinus rhythm.
Dosage and AdministrationAdults
IV Initial infusion: At least 60 kg (at least 132 lbs) 1 mg (1 vial) infused over 10 min; less than 60 kg (less than 132 lbs) 0.01 mg/kg (0.1 mL/kg) infused over 10 min. If the arrhythmia does not terminate within 10 min after the end of the initial infusion, a second 10 min infusion of equal strength may be administered 10 min after completion of the first infusion.
- For IV administration only.
- May be administered undiluted or further diluted in 50 mL of either normal saline or D5W.
- Store unopened vials at room temperature (59° to 86°F).
- Diluted medication may be stored for up to 24 h at room temperature (59° to 86°F), or for 48 h refrigerated (36° to 46°F).
Drug InteractionsConcomitant Class Ia and III antiarrhythmic agents (eg, amiodarone, disopyramide, procainamide, quinidine, sotalol)
Do not give concurrently. Withhold for 5 half-lives prior to and for 4 h after ibutilide infusion.Medications that prolong the QT interval (eg, phenothiazines, tricyclic and tetracyclic antidepressants)
Potential for proarrhythmia may be increased.Digoxin
Cardiotoxicity (supraventricular arrhythmia) due to excessive digoxin concentrations may be masked.
Laboratory Test Interactions
None well documented.
Nonsustained monomorphic ventricular extrasystoles and ventricular tachycardia (VT); sinus; supraventricular sustained and nonsustained polymorphic VT; hypotension; postural hypotension; hypertension; bundle branch block; sustained polymorphic VT; AV block; sinus bradycardia; QT segment prolongation; palpitations.
Experienced physician/equipped facility.
Potentially fatal arrhythmias have occurred and require administration in a setting of continuous ECG monitoring and personnel trained in identification and treatment of acute ventricular arrhythmias, particularly polymorphic ventricular tachycardia.Patient selection
Patients with chronic atrial fibrillation have a strong tendency to revert after conversion to sinus rhythm, and treatment to maintain sinus rhythms carry risks. Patients for ibutilide therapy should be carefully selected.
Category C .
Safety and efficacy not established.
No age-related differences in safety and efficacy have been observed.
Correct hypokalemia/hypomagnesemia to reduce potential for proarrhythmia.
Patients with atrial fibrillation more than 2 to 3 days must be adequately anticoagulated, generally for at least 2 wk before attempted conversion.
CNS toxicity, rapid gasping breathing, convulsions, ventricular ectopy, ventricular tachycardia, AV block.
- Advise patient that this is a short-term treatment for arrhythmia, and long-term oral medications will likely be required for control if this therapy is successful.
- Teach patient and family how to take blood pressure and pulse for home management with medications.
- Advise patient to report any chest pain, shortness of breath, palpitations, fluttering in the chest, headache, or faintness immediately to the health care provider while the medication is infusing.
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