Class: Interferons

Name: Interferon beta-1b (Betaseron®, Extavia®); interferon beta-1a (Avonex®, Rebif®); peginterferon beta-1a (Plegridy®)

General Dosage: All are injected and differ by dose and frequency of injection.

Mechanism of Action: All work by decreasing ability of lymphocytes to enter the brain.

Effectiveness: Compared to placebo, decrease relapses by about 30%; modestly slows progression of disability; no measurable effect on brain atrophy.

Possible Side Effects: Post-injection flu-like symptoms common (49%), liver toxicity. Rarely, seizures, allergic reactions, congestive heart failure, increased peripheral blood counts, or thrombotic microangiopathy can occur. Depression may be common, but suicide or psychosis are very rare.


Interferons are a class of drugs that were approved for us in treating multiple sclerosis beginning in 1993, making them among the first drugs available that specifically treat MS. They work by decreasing inflammation and preventing nerve damage that may cause symptoms of multiple sclerosis.

Video recorded in 2015.