Drug General Information (ID: DDIKW38RTU)
Drug Name			Ibutilide		Drug Info		Propafenone		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiarrhythmic Agents				Antiarrhythmic Agents
Structure

Mechanism of Ibutilide-Propafenone Interaction (Severity Level: Major)
Increased risk of prolong QT interval Click to Show/Hide Mechanism Graph
Drug Name		Ibutilide				Propafenone
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 Ibutilide and Propafenone

Recommended Action
Management		Propafenone product labeling recommends that concomitant use with Class IA and III antiarrhythmic agents be avoided. In addition, these agents should be withheld for at least 5 half-lives prior to dosing with propafenone. Close monitoring of clinical response, ECG, and drug levels is recommended if concomitant use is required. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

References
1	Buss J, Neuss H, Bilgin Y, Schlepper M "Malignant ventricular tachyarrhythmias in association with propafenone treatment." Eur Heart J 6 (1985): 424-8. [PMID: 4043097]
2	Hii JT, Wyse DG, Gillis AM, et al "Propafenone-induced torsade de pointes: cross-reactivity with quinidine." Pacing Clin Electrophysiol 14 (1991): 1568-70. [PMID: 1721143]
3	Klein RC, Huang SK, Marcus FI, et al "Enhanced antiarrhythmic efficacy of propafenone when used in combination with procainamide or quinidine." Am Heart J 114 (1987): 551-8. [PMID: 3630896]
4	Product Information. Rhythmol (propafenone). Knoll Pharmaceutical Company, Whippany, NJ.
5	Product Information. Rythmol SR (propafenone). GlaxoSmithKline, Research Triangle Park, NC.
6	Zehender M, Hohnloser S, Geibel A, et al "Short-term and long-term treatment with propafenone: determinants of arrhythmia suppression, persistence of efficacy, arrhythmogenesis, and side effects in patients." Br Heart J 67 (1992): 491-7. [PMID: 1622701]