Tysabri is approved as single therapy for the treatment of people with relapsing forms of multiple sclerosis (MS) to reduce the frequency of flare-ups and delay progression of physical disability.
After the FDA initially approved Tysabri, the drug's manufacturer took the drug off the U.S. market due to reports of a rare, but serious brain infection called PML (progressive multifocal leukoencephalopathy). But the drug returned to the market after the drugmaker included a risk-minimization program...
Your doctor will decide which type of botulinum toxin is appropriate for you.
Despite the fact that the drugs are used for a variety of medical problems, the FDA, as of this date, has not yet approved the use of these treatments for MS-related spasticity. Botox, Myobloc, Xeomin, and Dysport are approved by the FDA for the treatment of a condition marked by repetitive contraction of the neck muscles (cervical dystonia), chronic migraine headaches, and uncontrollable blinking of the eyelids (blepharospasm). Botox is commonly used to treat wrinkles.
What Is Spasticity?
Spasticity refers to a wide range of involuntary muscle contractions that result in muscle spasms or stiffness. Spasticity interferes with voluntary muscle movement and usually involves the muscles of the legs and/or arms.
Spasticity is the result of an imbalance in the central nervous system, caused by a trauma or disease in the brain and/or spinal cord. This imbalance causes hyperactive muscle stretch reflexes, which result in involuntary contractions and increased muscle tone.
Some doctors believe that an increased sensitivity in the parts of the muscles that are responsible for contracting (tightening), relaxing and stretching the muscles contribute to spasticity.
How Does Botulinum Toxin Work?
Normally, the nerves in the body send electrical messages to the muscles so that they will contract and move. This messages are transmitted from the nerves to the muscles by a substance called acetylcholine. Botulinum toxin works to block the effect of acetylcholine on the muscle, resulting in weakness or paralysis.
How Are Botulinum Toxin Treatments Given?
Botulinum toxin is administered as an intramuscular injection (into the muscle). Your doctor will determine which muscles need to be injected to reduce the degree of spasticity.
If the muscles to be injected are small or difficult to reach, it may be necessary to record electric signals from the muscles, to ensure that the appropriate muscles are receiving the injected medication.
A very fine needle is used for the injection. Although the medication usually does not sting or cause irritation, some people report minor and temporary discomfort from the injection.
The effect of the medication begins to appear from one to two weeks after the injection. The muscles injected should start to relax.