LINKAvonex is a form of interferon beta. Interferons are proteins naturally produced by the body to help fight viral infections and regulate the immune system.

Avonex is made up of the same arrangement of amino acids, the building blocks of proteins, as the interferon beta produced by the body.

MS is thought to be a disease in which the body's immune system responds against myelin, the insulation surrounding nerve fibers, causing its deterioration.

It is believed that Avonex regulates the body's immune response to decrease the attack against myelin.

With Avonex, more medicine gets into the bloodstream and stays in the body longer because injections are given into the muscle. This is part of the reason that Avonex injections are only administered once-a-week.

Other treatments for MS are given by subcutaneous injection - under the skin - and must be taken every day or every other day.

Unlike injections given under the skin, injections into the muscle rarely produce uncomfortable and unsightly injection site reactions.

Most people can adjust well to treatment with Avonex. But as with all MS treatments, side effects can occur.
The most common side effects associated with Avonex treatment are flu-like symptoms, muscle ache, fever, and chills.

Other common side effects seen, but not statistically different between Avonex and control groups in clinical studies were headache (Avonex: 67%, placebo: 57%), pain (Avonex: 24%, placebo: 20%), and asthenia (weakness) (Avonex: 21%, placebo 13%).

These side effects usually go away within a day after the injection.

There are several ways to manage these flu-like symptoms, including taking an analgesic such as Tylenol.

Avonex should be used with caution in people with depression and in people with seizure disorders, and should not be be used by pregnant women.

People with cardiac disease should be closely monitored. Routine periodic blood chemistry and hematology tests are recommended during treatment, as well.