Classifications: antiarrhythmic agent, class iii;
Therapeutic: antiarrhythmic agent, class iii

Prototype: Amiodarone HCl
Pregnancy Category: C


0.1 mg/mL injection


Ibutilide is a Class III antiarrhythmic agent. It prolongs the cardiac action potential and increases both atrial and ventricular refractoriness without affecting conduction (i.e., Class III antiarrhythmic electrophysiologic effects).

Therapeutic Effect

It is used to treat recently occurring atrial arrhythmias. Like other Class III antiarrhythmic drugs it may produce proarrhythmic effects that can be life threatening.


Rapid conversion of atrial fibrillation or atrial flutter of recent onset.


Hypersensitivity to ibutilide, hypokalemia, hypomagnesemia; pregnancy (category C). Safety and effectiveness in children <18 y are not established.

Cautious Use

History of CHF, cardiac ejection fraction of 35% or less, recent MI, prolonged QT intervals, ventricular arrhythmias; renal or liver disease, cardiovascular disorder other than atrial arrhythmias, other drugs that prolong QT interval, lactation.

Route & Dosage

Atrial Fibrillation or Flutter
Adult: IV <60 kg, 0.01 mg/kg, may repeat in 10 min if inadequate response; ≥60 kg, 1 mg, may repeat in 10 min if inadequate response


  • Hypokalemia and hypomagnesemia should be corrected prior to treatment with ibutilide.
  • Class Ia and other class III antiarrhythmic drugs should not be given concurrently or within 4 h of ibutilide.

PREPARE: Direct: Give undiluted.  IV Infusion: Contents of 1 mg vial may be diluted in 50 mL of D5W or NS to yield 0.017 mg/mL.  

ADMINISTER: Direct/IV Infusion: ??Give a single dose by direct injection or infusion over 10 min.??Stop injection/infusion as soon as presenting arrhythmia is terminated or with appearance of ventricular tachycardia or marked prolongation of QT or QTc

  • Store diluted solution up to 24 h at 15°–30° C (59°–86° F) or 48 h refrigerated at 2°–8° C (36°–46° F).

Adverse Effects (≥1%)

CNS: Headache. CV: Proarrhythmic effects (sustained and nonsustained polymorphic ventricular tachycardia), AV block, bundle branch block, ventricular extrasystoles, hypotension, postural hypotension, bradycardia, tachycardia, palpitations, prolonged QT segment. GI: Nausea.


Drug: Increased potential for proarrhythmic effects when administered with phenothiazines, tricyclic antidepressants, amiodarone, disopyramide, quinidine, procainamide, sotalol may cause prolonged refractoriness if given within 4 h of ibutilide.


Onset: 30 min. Metabolism: In liver. Elimination: 82% in urine, 19% in feces. Half-Life: 6 h (range 2–21 h).

Nursing Implications

Assessment & Drug Effects

  • Monitor for therapeutic effectiveness. Conversion to normal sinus rhythm normally occurs within 30 min of initiation of infusion.
  • Observe with continuous ECG, BP, and HR monitoring during and for at least 4 h after infusion or until QTc has returned to baseline. Monitor for longer periods with liver dysfunction or if proarrhythmic activity is observed.

Patient & Family Education

  • Consult physician and understand the potential risks of ibutilide therapy.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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