Multiple sclerosis is an autoimmune disorder that affects the myelin sheath in the central nervous system. A patient's immune system damages the myelin sheath, which covers the neuron's axon; this damage affects how signals are transmitted in the brain and spinal cord. The inflammation with multiple sclerosis targets oligodendrocytes, the glial cell that makes up the myelin sheath in the central nervous system. Multiple sclerosis does not affect the peripheral nervous system, as the myelin on the nerves outside of the brain and spinal cord are made from a different type of glial cell: Schwann cells. The onset of symptoms occurs most frequently between ages 20 and 40, with
No cure exists for multiple sclerosis, though several treatment options exist. Multiple sclerosis patients may take disease-modifying medications, which lower how often they have relapses of the disease and how severe these relapses are. The U.S. Food and Drug Administration has approved eight disease-modifying medications for multiple sclerosis, which include Tysabri (natalizumab), Rebif and Avonex (interferon beta-1a), Betaseron and Extavia (interferon beta-1b), Novantrone (mitoxantrone), Copaxone (glatiramer acetate) and Gilenya (fingolimod). These disease-modifying medications have different methods of delivery. Anonex is an injection done into the muscle, while Extavia, Copaxone, Betaseron and Rebif are injections done under the skin. Patients taking Novantrone and Tysabri receive an IV: Novantrone is administered four times a year, while Tysabri is administered every four weeks, according to the National MS Society's booklet on disease-modifying medication. The last FDA approved disease-modifying medication for multiple sclerosis, Gilenya, is taken orally.
Multiple sclerosis patients may take other medications,