Drug General Information (ID: DDIUQISO5T)
Drug Name			Interferon beta-1b		Drug Info		Natalizumab		Drug Info
Drug Type		Interferons				Monoclonal antibody
Therapeutic Class		Immunomodulatory Agents				Selective Immunosuppressants

Mechanism of Interferon beta-1b-Natalizumab Interaction (Severity Level: Major)
Additive immunosuppressive effects Click to Show/Hide Mechanism Graph
Drug Name		Interferon beta-1b				Natalizumab
Mechanism		Immunosuppressive effects				Immunosuppressive 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 Interferon beta-1b and Natalizumab

Recommended Action
Management		Although data are limited with respect to the risk of PML, the use of natalizumab in combination with immunomodulatory agents including interferon beta should generally be avoided. All patients treated with natalizumab should be monitored closely and the drug discontinued immediately at the first sign or symptom suggestive of PML. However, it is not known if early detection of PML and discontinuation of natalizumab will mitigate the disease.

References
1	Product Information. Tysabri (natalizumab). Elan Pharmaceutical/Athena Neurosciences Inc, South San Francisco, CA.