Drug General Information (ID: DDISPUCKED)
Drug Name			Dofetilide		Drug Info		Polythiazide		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiarrhythmic Agents				Antihypertensive Agents
Structure

Mechanism of Dofetilide-Polythiazide Interaction (Severity Level: Major)
Increased risk of ventricular arrhythmias Click to Show/Hide Mechanism Graph
Drug Name		Dofetilide				Polythiazide
Mechanism 1		Prolong QT interval				Hypokalemia
Key Mechanism Factor 1
		Factor Name		Ventricular arrhythmias
		Factor Description		Ventricular arrhythmias are abnormal heart rhythms that cause your heart's lower chambers to pump blood instead of pumping it. This can limit or stop your heart from supplying blood to your body. While some of these arrhythmias are harmless and do not cause symptoms, others can have serious, even fatal, effects on your body.
Mechanism Description		Increased risk of ventricular arrhythmias by the combination of Dofetilide and Polythiazide
Mechanism 2		Prolong QT interval				Hypomagnesemia
Key Mechanism Factor 2
		Factor Name		Ventricular arrhythmias
		Factor Description		Ventricular arrhythmias are abnormal heart rhythms that cause your heart's lower chambers to pump blood instead of pumping it. This can limit or stop your heart from supplying blood to your body. While some of these arrhythmias are harmless and do not cause symptoms, others can have serious, even fatal, effects on your body.
Mechanism Description		Increased risk of ventricular arrhythmias by the combination of Dofetilide and Polythiazide

Recommended Action
Management		Caution is advised if dofetilide must be used concomitantly with medications that can cause potassium and/or magnesium disturbances. Serum electrolytes should be evaluated and any abnormalities corrected prior to initiating therapy with dofetilide. During therapy, potassium concentrations should be kept above 4 mEq/dL and magnesium concentrations above 1.8 mg/dL. Patients should also have frequent ECGs and be monitored for serious arrhythmias when QT intervals are prolonged. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, palpitations, or syncope.

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