Concomittant antiarrythmias- Disopyramide, quinidine and procainamide and other drugs such as amiodarone and solatol should not be given concomittantly with ibutilide or within 4 hours postinfusion because of their potential to prolong refractriness.

Other drugs that prolong QT intervals- potential for proarrhythmias may increase with administration of ibutilide to patients who are being treated with drugs that prolong QT interval, such as phenothiazines, tricyclic and tetracyclic antidepressants.

Digoxin- supraventricular arrhythmias may mask the cardiotoxicity associated with excessive digoxin levels

Atrial fibrillation/flutter

Antiarrhythmic agents include-

Group I -  Moricizine, Qunidine, Procainamide, Disopyramide, Lidocaine, Phenytoin, Tocainide,
                 Mexiletine, Flecanide,  Propafenone
Group II- Propranolol, Esmolol, Acebutol
Group III- Bretylium, Amiodarone, Solatol
Group IV- Verapramil, Digoxin, Adenosine

Drug well tolererated- important adverse events- non-sustained monomorphic ventricular extrasystoles, tachycardia/supraventricular tachycardia, nausea, palpitation, suptraventricular extrasystoles.

Hypersensitivity to ibutilide

Special precautions:

Heart block- ibutilide treated patients with reports of reversible heart block.

Indications:

Atrial fibrillation/flutter

Dosage:

Patients more than 60kg - one vial (1mg) -initial infusion over 10 minutes less than 60kg- 0.1ml.kg (0.01mg/kg)

Pharmacology:

Ibutilide is an antiarrhythmic drug with predominantly cardiac action potential prolongation. Ibutilide prolongs action potential duration in isolated adult cardiac mycocytes and increases both atrial and ventricular refractoriness in vivo.

Pharmacokinetics:

After IV infusion, ibutilide concentrations rapidly decrease in a multiexpoential fashion. The drug is cleared rapidly and highly distributed in patients being treated for atrial flutter or atrial fibrillation. The elimination half-life averages about 6 hours.

Pregnancy:

Do not administer to pregnant woman unless clinical benefit outweighs potential risks to the fetus.

Lactation:

Discourage breast feeding during therapy

Children:

Safety and efficacy in children have not been established.