Multiple sclerosis (MS) is an autoimmune disease caused by the body's own immune system attacking the protective covering (called myelin) around the nerves. MS affects over 400,000 Americans and women are 2 to 3 times more likely to develop the disease than men according to statistics provided by the National Multiple Sclerosis Society. The disease can have a variety of symptoms depending upon which nerves are affected and the extent of the damage, ranging from mild numbness and tingling in parts of the body to total paralysis. If the nerves themselves are damaged they cannot be repaired therefore treatment with drugs aims to slow down the disease and treat the symptoms.
Corticosteroids
Corticosteroids, a classification of drugs used to reduce inflammation, are the most common treatment prescribed for MS. Diagnosing MS, especially in the beginning stages, can be difficult because symptoms can come and go often subsiding for months at a time. Symptoms can then reappear, known as an attack, flare-up or exacerbation of the disease, presenting new symptoms or an increase in intensity of the old symptoms. These exacerbations are caused by inflammation in the central nervous system resulting in more damage to the myelin.
Symptoms during a flare-up can be severe, including loss of vision, severe weakness and poor balance that can interfere with daily activities. Corticosteroids such as prednisone, methylprednisolone and dexamethasone, are prescribed to decrease the inflammation and resolve the flare-up episode more quickly.
Interferons
Interferon drugs are medications that mimic the actions of natural interferons, a specific type of protein that works as part of the body's immune response to attack invaders of the body. Interferon medications are known as disease modifying drugs because they can decrease the number of attacks on the myelin therefore slowing the course of the disease.
There are currently three different interferon drugs approved by the Food and Drug Administration (FDA) to treat MS. These include two forms of interferon B1a and interferon B1b. Although these drugs are effective in slowing the progression of MS, they cause abnormal liver function in nearly one-third (36 percent) of all patients according to information provided by the American Academy of Neurology.
Monoclonal Antibodies
Monoclonal antibodies are drugs that are produced by injecting mice with the human immune cells which in this case are those that are thought to attack the myelin. The mice then produce antibodies against this specific antigen that are combined with human antibodies (so they are not considered as a foreign substance in the body) and purified into an injectible medication.
Natalizumab is a monoclonal antibody drug approved by the FDA to treat MS. Natalizumab prevents the immune cells from crossing the blood-brain barrier into the spinal cord and brain, therefore reducing the flare-ups. This medication is only used on patients who have not responded to other therapies because it can cause progressive multifocal leukoencephalopathy (PML), a potentially deadly brain infection.
