Dofetilide

Dofetilide is a prescription medicine used to treat an irregular heartbeat (atrial fibrillation or atrial flutter).

• Dofetilide is available under the following different brand names: Tikosyn

Adult dosage

Capsule

• 125mcg
• 250mcg
• 500mcg

Conversion of Atrial Fibrillation/Flutter to Normal Sinus Rhythm

Adult dosage

• QTc must be less than 440 msec (or less than 500 msec with ventricular conduction abnormalities) before initiating the first dose; contraindicated if more than 440 msec (or more than 500 msec with ventricular conduction abnormalities)
• Initial dose
  • CrCl above 60 mL/min: 500 mcg orally every 12 hours
  • CrCl 40-60 mL/min: 250 mcg orally every 12 hours
  • CrCl 20-40 mL/min: 125 mcg orally every 12 hours
  • CrCl below 20 mL/min: Contraindicated
• Sinus Rhythm Maintenance after Conversion
  • Post initial dose adjustment based on QTc (2-3 hours after initial dose)
  • If QTc increases less than 15% of baseline, continue current dose
  • If QTc increases more than 15% or more than 500 msec (550 msec with ventricular conduction abnormalities) decrease dose as follows:
  • If the initial dose is 500 mcg every 12 hours, decrease to 250 mcg every 12 hours
  • If the initial dose is 250 mcg every 12 hours, decrease to 125 mcg every 12 hours
  • If the initial dose is 125 mcg every 12 hours, decrease to 125 mcg once daily

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

Common side effects of Dofetilide include:

• headache,
• chest pain,
• dizziness,
• nausea,
• diarrhea,
• stomach pain,
• sleep problems (insomnia),
• back pain,
• skin rash,  and
• cold symptoms such as stuffy nose, sneezing, or sore throat.

Serious side effects of Dofetilide include:

• chest pain,
• fainting,
• faster or more irregular heartbeat, 
• severe dizziness, and
• signs of electrolyte imbalance: severe diarrhea, unusual sweating, vomiting, not hungry (loss of appetite), and increased thirst (drinking more than normal).

Rare side effects of Dofetilide include:

• Torsade de pointes.

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Dofetilide has severe interactions with at least 29 other drugs.
• Dofetilide has serious interactions with at least 113 other drugs.
• Dofetilide has moderate interactions with at least 86 other drugs.
• Dofetilide has minor interactions with the following drug:
  • isavuconazonium sulfate

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

Contraindications

• Hypersensitivity
• Congenital or acquired long QT syndromes; do not use with baseline QTc more than 440 msec (500 msec with ventricular conduction abnormalities)
• Concomitant use of cation transport system inhibitors (eg, verapamil, cimetidine, trimethoprim, ketoconazole, prochlorperazine, dolutegravir, and megestrol); each of these drugs cause a substantial increase in dofetilide plasma concentrations
• Severe renal impairment: CrCl less than 20 mL/min

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Dofetilide?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Dofetilide?”

Cautions

• Atrioventricular block, bradycardia, electrolyte imbalance, patients taking potassium-depleting diuretics, moderate QT interval prolongation before treatment, proarrhythmic events, liver disease, renal impairment
• Coadministration of drugs that prolong QT interval and other antiarrhythmic agents: phenothiazines, cisapride, bepridil, TCAs, oral macrolides, class I or class III antiarrhythmics & amiodarone
• Grapefruit juice may increase levels; avoid concurrent use
• Magnesium and potassium serum levels should be maintained within the normal range to avoid QTc prolongation

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy.
• Lactation
  • Excretion in milk unknown/not recommended