Drug General Information (ID: DDIB3GYS6K)
Drug Name			Clozapine		Drug Info		Procainamide		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antipsychotic Agents				Antiarrhythmic Agents
Structure

Mechanism of Clozapine-Procainamide Interaction (Severity Level: Major)
Additive myelosuppressive effects Click to Show/Hide Mechanism Graph
Drug Name		Clozapine				Procainamide
Mechanism 1		Hematologic toxicity				Hematologic toxicity
Key Mechanism Factor 1
		Factor Name		Myelosuppressive effects
		Factor Description		Myelosuppression, also known as bone marrow suppression, is a decrease in bone marrow activity that leads to a decrease in the production of blood cells. Some blood cell disorders include: erythrocytopenia (anemia), leukopenia (neutropenia), and thrombocytopenia (thrombocytopenia).
Mechanism Description		Additive myelosuppressive effects by the combination of Clozapine and Procainamide
Increased risk of prolong QT interval Click to Show/Hide Mechanism Graph
Drug Name		Clozapine				Procainamide
Mechanism 2		Prolong QT interval				Prolong QT interval
Key Mechanism Factor 2
		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 Clozapine and Procainamide

Recommended Action
Management		The use of clozapine in combination with other agents having a well-known potential to cause agranulocytosis or otherwise suppress bone marrow function is considered contraindicated. The concurrent use of procainamide with other medications that can prolong the QT interval should preferably be avoided unless benefits are anticipated to outweigh the risks.

References
1	Product Information. Clozaril (clozapine). Novartis Pharmaceuticals, East Hanover, NJ.
2	Product Information. Procan SR (procainamide). Parke-Davis, Morris Plains, NJ.
3	Trujillo TC, Nolan PE "Antiarrhythmic agents - Drug interactions of clinical significance." Drug Safety 23 (2000): 509-32. [PMID: 11144659]
4	Yamreudeewong W, DeBisschop M, Martin L, Lower D "Potentially Significant Drug Interactions of Class III Antiarrhythmic Drugs." Drug Saf 26 (2003): 421-38. [PMID: 12688833]