Key takeaways
Rebif (interferon beta-1a) and Tysabri (natalizumab) are both used to treat relapsing forms of multiple sclerosis (MS), but they have some key differences. Rebif is an injectable biologic that you administer under the skin three times a week, while Tysabri is given as an IV infusion once a month by a healthcare provider. Rebif can cause flu-like symptoms and injection site reactions, whereas Tysabri can lead to serious infections and liver problems. Tysabri also requires enrollment in the TOUCH Prescribing Program due to its risk of a severe brain infection called progressive multifocal leukoencephalopathy (PML). Additionally, both Rebif and Tysabri are available only as a brand-name medication. Rebif has been around longer and has more research backing its use. Both medications can affect your immune system, but Tysabri's side effects are generally more severe and require closer monitoring.
