Dofetilide


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Atrial fibrillation; Atrial flutter Initial: 500 mcg bid. Reduce dose if QT interval is prolonged after 1st dose, discontinue if QT interval is >500 milliseconds.
Dosage Details
Oral
Atrial fibrillation, Atrial flutter
Adult: Initially, 500 mcg bid. Reduce maintenance dose if QT interval is prolonged after the 1st dose, discontinue if QT interval is >500 milliseconds.
Renal Impairment
CrCl (mL/min) Dosage
<20 Contraindicated
20-39 Initially, 125 mcg bid.
40-60 250 mcg bid.
Administration
May be taken with or without food.
Contraindications
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.
Special Precautions
Patient w/ 2nd- or 3rd-degree heart block and/or sick sinus syndrome (unless w/ a functional pacemaker), electrolyte imbalance. Severe hepatic and renal impairment.
Adverse Reactions
Headache, chest pain, dizziness, resp tract infection, dyspnoea, nausea, flu syndrome, insomnia, accidental injury, diarrhoea, rash, back/abdominal pain.
Potentially Fatal: Serious ventricular arrhythmias, primarily torsade de pointes.
MonitoringParameters
Determine CrCl and QTc interval (or QT interval if heart rate is <60 beats/min) prior to initiation of therapy. Closely monitor ECG (determine QTc interval w/in 2-3 hr after the 1st dose and after each subsequent doses) for at least 3 days or 12 hr after electrical or pharmacologic conversion to normal sinus rhythm). Re-evaluate renal function and QTc interval every 3 mth thereafter. Monitor K and Mg levels at baseline and during therapy.
Overdosage
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.
Drug Interactions
Increased plasma concentration when used w/ drugs secreted by renal tubular cationic transport (e.g. amiloride, metformin, triamterene). Increased risk of toxicity when used w/ QT prolonging agents (e.g. class I/III antiarrhythmics, bepridil, cisapride, phenothiazines, TCAs, certain fluoroquinolones and oral macrolides).
Potentially Fatal: Increased risk of torsade de pointes when used w/ hydrochlorothiazide (w/ or w/o triamterene), verapamil, and renal cation transport inhibitors (e.g. cimetidine, dolutegravir, trimethoprim, ketoconazole, prochlorperazine, megestrol).
Food Interaction
Increased plasma concentration when taken w/ grapefruit juice.
Action
Description: Dofetilide selectively inhibits the rapidly activating component of the K channel involved in repolarisation of cardiac cells, thereby prolonging the action potential duration and effective refractory period in both atrial and ventricular cardiac tissue.
Pharmacokinetics:
Absorption: Well absorbed. Bioavailability: >90%. Time to peak plasma concentration: 2-3 hr.
Distribution: Volume of distribution: 3 L/kg. Plasma protein binding: 60-70%.
Metabolism: Undergoes limited metabolism; mediated to some extent by CYP3A4 isoenzyme to form metabolites via N-dealkylation and N-oxidation.
Excretion: Via urine (80%, mainly as unchanged drug and the remaining as inactive or minimally active metabolites). Terminal half-life: Approx 10 hr.
Chemical Structure

Click on icon to see table/diagram/image
Storage
Store between 20-25°C. Protect from moisture and humidity.
MIMS Class
ATC Classification
C01BD04 - dofetilide ; Belongs to class III antiarrhythmics.
Disclaimer: This information is independently developed by MIMS based on Dofetilide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign up for free
Already a member? Sign in