Avonex® (
interferon beta-1a) is a prescription medication approved for treating
multiple sclerosis (also known as
MS, for short). It is given as weekly intramuscular injections (injections into a muscle). Avonex belongs to a group of medications known as interferons.
Multiple sclerosis is a central nervous system (brain and spinal cord) disease and is the leading cause of disability among young adults. There are four basic
types of multiple sclerosis. The most common pattern is relapsing-remitting MS, which consists of episodes of symptoms that lasts for days or weeks, followed by a periods of no symptoms for weeks or months. A less common pattern of multiple sclerosis is progressive MS, a steady worsening of symptoms from the first sign of illness. The two other main forms of multiple sclerosis include secondary-progressive and progressive-relapsing. Avonex is approved for the treatment of multiple sclerosis in people with relapsing forms of the disease.
Multiple sclerosis research has shown that during a multiple sclerosis attack, inflammation occurs in random areas of the white matter of the central nervous system. These areas of inflammation are called
plaques. This process is followed by destruction of myelin, the fatty covering that insulates nerve cell fibers in the brain and spinal cord. Myelin facilitates the smooth, high-speed transmission of electrochemical messages between the brain, the spinal cord, and the rest of the body. When myelin is damaged, transmission of messages through that part of the nervous system may be slowed or blocked completely, leading to diminished or lost function. It is not known exactly what causes this damaging process to occur
(see Multiple Sclerosis Causes for more information).
- Muscle weakness
- Tingling or numbness
- Loss of balance
- Blurred or double vision and/or eye pain
- Fatigue (see Multiple Sclerosis Fatigue).