ibutilide fumarate
Pharmacologic class: Ibutilide derivative
Therapeutic class: Antiarrhythmic (class III)
Pregnancy risk category C
FDA Box Warning
• Drug can cause potentially fatal arrhythmias-particularly sustained polymorphic ventricular tachycardia, usually in association with QT prolongation (torsades de pointes). In studies, these arrhythmias arose within several hours of administration. They can be reversed if treated promptly. Drug must be given in setting of continuous ECG monitoring and by personnel trained in identifying and treating acute ventricular arrhythmias. Patients with atrial fibrillation of more than 2 to 3 days' duration must be adequately anticoagulated, generally for at least 2 weeks.
• Patients with chronic atrial fibrillation tend to revert after conversion to sinus rhythm, and treatments to maintain sinus rhythm carry risks. Therefore, patients to be treated with drug should be selected carefully, with expected benefits of maintaining sinus rhythm outweighing drug's immediate risks and risks of maintenance therapy, and with drug offering benefits over alternative management.
Action
Prolongs myocardial action potential by slowing repolarization and atrioventricular (AV) conduction
Availability
Solution: 0.1 mg/ml in 10-ml vials
Indications and dosages
➣ To convert atrial fibrillation or flutter to sinus rhythm
Adults weighing more than 60 kg (132 lb): 1 vial (1 mg) by I.V. infusion over 10 minutes. May repeat after 10 minutes if arrhythmia persists.
Adults weighing less than 60 kg (132 lb): 0.1 ml/kg (0.01 mg/kg) by I.V. infusion over 10 minutes. May repeat after 10 minutes if arrhythmia persists.
Contraindications
• Hypersensitivity to drug or its components
Precautions
Use cautiously in:
• ventricular and AV arrhythmias
• pregnant or breastfeeding patients.
Administration
☞ Monitor ECG continuously during and after infusion. Stop infusion immediately if ventricular tachycardia occurs.
• As appropriate, administer diluted or undiluted. To dilute, add 10-ml vial to 50 ml of normal saline solution or dextrose 5% in water, to yield a concentration of 0.017 mg/ml.
• Infuse over 10 minutes.
☞ Don't give with amiodarone, disopyramide, quinidine, procainamide, or sotalol, because of increased risk of dangerous arrhythmias.
Adverse reactions
CNS: headache, light-headedness, dizziness, numbness or tingling in arms
CV: hypotension, hypertension, bradycardia, bundle-branch block, ventricular extrasystoles, ventricular arrhythmias, ventricular tachycardia, AV heart block, heart failure
GI: nausea
GU: renal failure
Interactions
Drug-drug. Amiodarone, disopyramide, quinidine, procainamide, sotalol: increased risk of dangerous arrhythmias
Antihistamines, phenothiazines, tricyclic antidepressants: increased proarrhythmic effect (prolonged QT interval)
Patient monitoring
• Before giving, assess electrolyte levels and correct abnormalities (especially involving potassium and magnesium), because hypokalemia and hypomagnesemia can lead to arrhythmias.
☞ Watch for premature ventricular contractions, sinus tachycardia, sinus bradycardia, and heart block.
• Monitor ECG during and for at least 4 hours after infusion.
☞ Keep emergency equipment (defibrillator, emergency cart and drug box, oxygen, suction, and intubation equipment) at hand during and for at least 4 hours after infusion.
• Monitor prothrombin time, International Normalized Ratio, and activated partial thromboplastin time if patient is receiving anticoagulant therapy.
Patient teaching
☞ Instruct patient to immediately report chest pain, dizziness, numbness, palpitations, headache, or difficulty breathing.
• Tell patient he'll be monitored closely for at least 4 hours after drug administration.