.png&w=384&q=75)
Maintenance of Normal Sinus Rhythm (Delay in AF/AFL Recurrence): Dofetilide is indicated for the maintenance of normal sinus rhythm (delay in time to recurrence of atrial fibrillation/atrial flutter [AF/AFl]) in patients with atrial fibrillation/atrial flutter of greater than one week duration who have been converted to normal sinus rhythm. Because Dofetilide can cause life-threatening ventricular arrhythmias, it should be reserved for patients in whom atrial fibrillation/atrial flutter is highly symptomatic. In general, antiarrhythmic therapy for atrial fibrillation/atrial flutter aims to prolong the time in normal sinus rhythm. Recurrence is expected in some patients
Conversion of Atrial Fibrillation/Flutter: Dofetilide is indicated for the conversion of atrial fibrillation and atrial flutter to normal sinus rhythm. Dofetilide has not been shown to be effective in patients with paroxysmal atrial fibrillation.
Dofetilide shows Vaughan Williams Class III antiarrhythmic activity. The mechanism of action is blockade of the cardiac ion channel carrying the rapid component of the delayed rectifier potassium current, IKr. At concentrations covering several orders of magnitude, dofetilide blocks only IKr with no relevant block of the other repolarizing potassium currents (e.g., IKs, IK1). At clinically relevant concentrations, dofetilide has no effect on sodium channels (associated with Class I effect), adrenergic alpha-receptors, or adrenergic beta-receptors.
Atrial fibrillation and atrial flutter: Initially, 500 mcg bid. Reduce maintenance dose if QT interval is prolonged after the 1st dose, discontinue if QT interval is >500 milliseconds.
Increased plasma concentration when used with drugs secreted by renal tubular cationic transport (e.g. amiloride, metformin, triamterene). Increased risk of toxicity when used with QT prolonging agents (e.g. class I/III antiarrhythmics, bepridil, cisapride, phenothiazines, TCAs, certain fluoroquinolones and oral macrolides).
Congenital or acquired long QT syndromes, baseline QT or QTc interval >440 millisecond (>500 millisecond in patients w/ ventricular conduction abnormalities). Severe renal impairment (CrCl <20 mL/min). Concurrent use of verapamil, cation transport system inhibitors and hydrochlorothiazide.
Headache, chest pain, dizziness, resp tract infection, dyspnoea, nausea, flu syndrome, insomnia, accidental injury, diarrhoea, rash, back/abdominal pain.
Category catagory C. Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.
Symptoms: Torsade de pointes.
Management: Supportive and symptomatic treatment. Administer charcoal slurry w/in 15 min of dofetilide admin. Admin of isoproterenol infusion and IV Mg sulfate may be useful in managing torsade de pointes.
Store between 20-25°C. Protect from moisture and humidity.
Dofetilide 125mcg