Class III antiarrhythmic, selective IKr blocker
ATC code: C01BD04 (Dofetilide)
Brand names
Tikosyn
Selectively blocks IKr potassium channels, prolonging repolarisation and effective refractory period in atria and ventricles. Renally excreted with minimal metabolism. REMS – inpatient initiation only with QTc and creatinine titration.
Second line
Dofetilide is a second-line antiarrhythmic for sinus rhythm maintenance in atrial fibrillation when amiodarone failed or is contraindicated. 2024 supports use in patients without heart failure. REMS requires inpatient initiation with continuous ECG monitoring for the first 3 days.
4 pairs found. Sorted from critical to minor.
Mechanism
Hydrochlorothiazide causes hypokalaemia and hypomagnesaemia; combined with dofetilide leads to torsades de pointes. Tikosyn Section 4.3 strict contraindication.
Symptoms
Torsades de pointes, syncope, cardiac arrest.
Management
Combination contraindicated. Use loop diuretic with potassium monitoring.
Mechanism
Ketoconazole inhibits CYP3A4 (dofetilide metabolism) and OCT2. Dofetilide rises 4-fold. Tikosyn Section 4.3.
Symptoms
Torsades de pointes.
Management
Combination contraindicated.
Mechanism
Trimethoprim inhibits renal OCT2 transporter clearing dofetilide. Levels double. Tikosyn Section 4.3 strict contraindication.
Symptoms
Torsades de pointes.
Management
Combination contraindicated.
Mechanism
Verapamil inhibits renal OCT2 transporter that clears dofetilide. Dofetilide doubles, QT prolongs. Tikosyn Section 4.3 strict contraindication.
Symptoms
Torsades de pointes within hours.
Management
Combination contraindicated.
Opens the checker prefilled with this drug. Pick the second one from your regimen.
Limited data. Use only if benefit outweighs risk.
Milk excretion data lacking. Breastfeeding not recommended.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Dofetilide is evaluated for the following indications with varying evidence strength: Atrial fibrillation (evidence tier B). See the full indication matrix with dosing and citations above on this page.
Common side effects of Dofetilide (≥ 1 in 100): Headache, Chest pain, Dizziness, Insomnia. See the Safety section for uncommon and serious reactions.
FDA category C. Limited data. Use only if benefit outweighs risk.
Milk excretion data lacking. Breastfeeding not recommended.
Dofetilide is contraindicated in: Baseline QTc above 440 ms; Creatinine clearance below 20 mL/min; Combination with verapamil, ketoconazole, cimetidine, trimethoprim, prochlorperazine, megestrol, hydrochlorothiazide (FDA REMS); Congenital long QT syndrome. Full list in the Safety section.