Drug General Information (ID: DDIOL9WC0K)
Drug Name			Dofetilide		Drug Info		Mexiletine		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiarrhythmic Agents				Antiarrhythmic Agents
Structure

Mechanism of Dofetilide-Mexiletine Interaction (Severity Level: Major)
Increased risk of prolong QT interval Click to Show/Hide Mechanism Graph
Drug Name		Dofetilide				Mexiletine
Mechanism		Prolong QT interval				Prolong QT interval
Key Mechanism Factor 1
		Factor Name		QT interval
		Factor Description		Long QT syndrome is a heart signaling disorder that can cause a fast, chaotic heartbeat (arrhythmia). Many people may not exhibit symptoms, and usually the condition is detected during routine medical tests. In others, the most common symptoms include: sudden fainting, palpitations, dizziness, seizures, sudden death.
Mechanism Description		Increased risk of prolong QT interval by the combination of Dofetilide and Mexiletine

Recommended Action
Management		Class I (e.g., disopyramide, quinidine, procainamide) and class III (e.g., amiodarone, ibutilide, sotalol) antiarrhythmic agents should be withheld for at least 3 half-lives before administering dofetilide. In the case of amiodarone with its unpredictable pharmacokinetics, dofetilide should not be initiated until serum amiodarone levels are below 0.3 mcg/mL or amiodarone has been withdrawn for at least three months.

References
1	Product Information. Tikosyn (dofetilide) Pfizer US Pharmaceuticals, Atlanta, GA.