Why is AVONEX given by an Intramuscular (IM) Injection?
To work effectively, some medications must be given intramuscularly, that is, in muscle tissue. The active ingredient in AVONEX is interferon beta-1a. Interferons are proteins that must be injected into the body. If taken in pill form, an interferon would be digested in the stomach and lose its active properties before it could provide any treatment benefits. Another advantage of an IM injection is that it can reduce the chance of having painful and unsightly injection-site reactions such as redness, swelling, and tissue death (necrosis) that may appear at SC injection sites. In the two phase III clinical studies, only 3% of those receiving AVONEX (n = 351) had skin reactions at the injection site.
