Treatment

Treatment of the Disease Process 

Exacerbations (also known as relapses or attacks)
Significant relapses are often treated with oral or intravenous steroids.  Dexamethasone (Decadron) and prednisone are the two most commonly used oral steroids, while methylprednisolone (Solumedrol) is the most frequently used intravenous steroid.  These medications are thought to decrease inflammation of multiple sclerosis lesions and restore the integrity to the barrier that separates the blood from the brain and spinal cord.  Steroid treatment has been shown to decrease the severity and duration of relapses, but it is not known whether this treatment has an effect on long-term outcome. 

Disease Course
In the past 15 years, there have been remarkable advances in developing medications that can alter the course of multiple sclerosis.  These drugs are known as disease-modifying medications.

There are currently six medications that are FDA-approved for use in multiple sclerosis.  Four of these medications are used most frequently.  These commonly used medications, which are given by injection, are two types of interferon beta-1a (Avonex, Rebif), interferon beta-1b (Betaseron), and glatiramer acetate (Copaxone).  The two less frequently used medications are natalizumab (Tysabri) and mitoxantrone (Novantrone).

Among the four commonly used medications, three are known as interferons and the other is a non-interferon known as glatiramer acetate (Copaxone).  Interferons are proteins that are produced by the body's immune system to help fight viruses, bacteria, parasites, and even tumors.  In multiple sclerosis, interferons exert therapeutic effects by decreasing the activity of the immune cells that are involved in inflammation and by blocking the movement of immune cells from the blood to the brain and spinal cord.  Glatiramer acetate (Copaxone) appears to produce its effects by activating immune cells in the blood.  These cells then travel to the brain and spinal cord where they inhibit harmful immune cells.

With regard to effectiveness, side effects, route of administration, and frequency of injections, there are important similarities and differences between these four medications:

• Interferon beta-1a (Avonex)
Avonex decreases the frequency of attacks, slows disability, and decreases MRI activity in people with multiple sclerosis.  It also delays the onset of multiple sclerosis in those who have clinically isolated syndrome (CIS), a condition in which people have a single attack and are at high risk for developing multiple sclerosis.  
Frequency:  once weekly
Route of administration:  intramuscular (into muscle)
Side effects:  flu-like symptoms; rarely, may cause depression, mild liver inflammation, and decreased white blood cell count

• Interferon beta-1b (Betaseron)
Betaseron decreases the frequency of attacks and decreases MRI activity in people with multiple sclerosis.  In addition, it delays the onset of multiple sclerosis in those with CIS.
Frequency:  every other day
Route of administration:  subcutaneous (under the skin)
Side effects:  flu-like symptoms, redness and swelling at injection sites; rarely, may cause depression, mild liver inflammation, and decreased white blood cell count

• Interferon beta-1a (Rebif)
Rebif reduces the frequency of attacks, slows disability, and decreases MRI activity in people with multiple sclerosis.  In people with CIS, it delays the onset of multiple sclerosis.
Frequency:  three times weekly
Route of administration:  subcutaneous (under the skin)
Side effects:  flu-like symptoms, redness and swelling at injection sites; rarely, may cause mild liver inflammation and decreased white blood cell count

• Glatiramer acetate (Copaxone)
Copaxone decreases the frequency of attacks and reduces MRI activity in people with multiple sclerosis. 
Frequency:  once daily
Route of administration:  subcutaneous (under the skin)
Side effects:  injection site reactions; rarely, may cause a brief reaction characterized by anxiety, flushing, and chest tightness

The less commonly used disease-modifying medications, which are given intravenously, are natalizumab (Tysabri) and mitoxantrone (Novantrone).  Both of these drugs have clear therapeutic effects, however they also have more serious side effects than interferons and glatiramer acetate (Copaxone).  Tysabri is an antibody which binds to immune cells and prevents them from crossing from the blood to the brain and spinal cord, while Novantrone acts by inhibiting the activity of several different types of immune cells.  When considering these drugs it is important to weight the potential risks and benefits:

• Natalizumab (Tysabri)
Tysabri produces prominent decreases in attack frequency and MRI activity in people with multiple sclerosis.  It also slows disability progression.  Importantly, it has rare but very serious side effects (see below).
Frequency:  every 28 days
Route of administration:  intravenous
Side effects:  mild reactions during infusion; rarely, may cause severe allergic reaction or, very rarely (estimated to be a risk of one in one thousand) may cause a serious brain infection (progressive multifocal leukoencephalopathy or PML) that is usually fatal

• Mitoxantrone (Novantrone)
Novantrone decreases attack frequency, slows disability, and reduces MRI activity in people with multiple sclerosis.  As with Tysabri, Novantrone has potentially serious side effects (see below). 
Frequency:  every three months
Route of administration:  intravenous
Side effects:  may decrease fertility; rarely may cause leukemia or serious injury to the heart muscle

There are several other medications that are used for a possible disease-modifying effect.  These medications are not FDA-approved for use in multiple sclerosis, but limited studies indicate that they may have therapeutic effects.  These medications include:
• azathioprine (Imuran)
• cyclophosphamide (Cytoxan)
• methotrexate
• mycophenolate (Cellcept)