Drug General Information (ID: DDIW2NJP0H)
Drug Name			Pyrimethamine		Drug Info		Trimetrexate		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antimalarial Agents				Antifungal Agents
Structure

Mechanism of Pyrimethamine-Trimetrexate Interaction (Severity Level: Moderate)
Additive immunosuppressive effects Click to Show/Hide Mechanism Graph
Drug Name		Pyrimethamine				Trimetrexate
Mechanism		Myelosuppressive effects				Myelosuppressive effects
Key Mechanism Factor 1
		Factor Name		Immunosuppressive effects
		Factor Description		Immunosuppression is when your immune system is not functioning as it should. The immune system is made up of cells, tissues and organs that help the body fight off infections. If the immune system is suppressed, an infection that your body was able to control may become serious or even fatal.
Mechanism Description		Additive immunosuppressive effects by the combination of Pyrimethamine and Trimetrexate

Recommended Action
Management		Caution is advised if pyrimethamine is prescribed in combination with other antifolate or myelosuppressive agents. Complete blood cell counts should be closely monitored. Treatment interruption or dose reduction may be required if toxicities such as mucositis or myelosuppression develop. Patients should be advised to contact their physician if they develop oral ulcers, painful swallowing, vomiting, diarrhea, and/or signs and symptoms of myelosuppression such as pallor, dizziness, fatigue, lethargy, fainting, easy bruising or bleeding, or signs of infection such as fever, chills, sore throat, body aches, and other influenza-like symptoms.

References
1	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
2	Multum Information Services, Inc. Expert Review Panel.