Botulinum Toxin

Botulinum toxin injection therapy (an injection of the neurotoxin clostridium botulinum) is sometimes used to treat dystonia, “a neuromuscular disorder that produces involuntary muscle contractions, or spasms” in the eyes, neck, face, voice box or the smooth muscle in the bladder. The goal of injection therapy is to reduce muscle spasm and pain, allowing patients to return to a more productive, independent lifestyle.

Approved by the FDA in 1989, the treatment originated in the mid-1980s, when a ophthalmologist used it to treat two eye muscle disorders: blepharospasm and strabismus. For more information about blepharospasm, you can visit www.blepharospasm.org.

Botulinum toxin therapy works by interrupting communication between the muscle and the nerve receptors, blocking the release of a chemical called acetylcholine, which carries messages between nerves cells. Small doses of sterilized toxin are injected into the affected muscles blocking the response, which would otherwise signal the muscle to contract. There are 8 different serotypes of botulinum toxin - A, B, C, C1 D, E, F, and G. Types A and B are now in use. Serotype C and F have been used, but have proven not to be of great benefit, since their effects last only approximately 4 weeks.

Simply said, botulinum toxin relaxes the overactive muscles. It does so by interrupting electrical transmissions between the nerve and the muscle at a place where they come together, the neuromuscular junction. This is also called “chemodenervation.”

To learn more about how botulinum toxin works, visit this link:
Botulinum Toxin at How Stuff Works

The injections need to be repeated every three to four months because neurons generate new nerve endings that reactivate the dystonia. Booster injections should be avoided to minimize the risk of antibody formation to the toxin, which then renders the toxin ineffective. Nor should the toxin be mixed with other agents.

Research on the two main types, botulinum toxin type A, (Botox Cosmetic) and botulinum type B (Myobloc) available for use in the U.S. indicate that the treatment is relatively safe when administered by a qualified neurologist. To find a qualified Center providing dystonia care, visit our Find a Doctor webpage today.

Dosing Guidelines

In patients with torticollis, about 100 to 400 U of botulinum toxin is injected into neck muscles. Onset of action takes about 3 to 5 days, and improvement is usually seen in 80% to 90% of patients. The main side effects are mild dysphagia and occasionally some difficulty keeping the head up if posterior muscles are overly weakened. For more information on torticollis, please visit the Spasmodic Torticollis website and Torticollis.org.

Blepharospasm requires injection of botulinum toxin into the orbicularis oculi muscle surrounding the eye, starting with a dose of 5 to 10 U per eye. Benefit usually occurs in at least 85% to 95% of patients within 5 to 7 days, with the main side effects being transient ptosis, difficulty closing the eye, diplopia, blurred vision, and a change in tearing.

Adductor spasmodic dysphonia patients are given botulinum toxin injections (0.5 to 5 U) into the vocal cords. Between 90% and 95% of patients note improvement in 1 to 3 days. Transient side effects include dysphagia and a breathy voice.

For jaw dystonia, botulinum toxin is injected into the masseter and temporalis muscles for jaw-closing dystonia and the digastric and pterygoid muscles for jaw-opening dystonia. Patients with writer’s cramp and limb dystonia require injections tailored to their specific dystonic symptoms.

According to the FDA, possible other side effects include: headache, respiratory infection, flu syndrome and nausea. Also, they recommend that the lowest effective dose should be used. Some patients experience temporary weakness in the group of muscles being treated. For example as mentioned above, ptosis (drooping eyelid) can develop after treating blepharospasm.

Source: PostGraduate Medicine, 2000 (Adler, C)

Some patients develop antibodies to the toxin with time, rendering the treatment ineffective. However, a second form of the toxin, Myobloc, is being used for patients who are resistant to botulinum toxin type A.

For more information on MyoBloc and dosing guidelines, please visit their website at myobloc.com.

Information on Botox can be found at www.medicalbotox.com

Information on Dysport can be found at www.dysport.com

Information about Xeonim ( Nt201 ) can be found at www.merzusa.com

PurTox Information coming from www.mentorcorp.com

Additional Links and Stories:

Is Botox Addictive?
What about Pain and Dystonia?
According to http://www.painmed.com in a study conducted at the Pain Evaluation & Treatment Center in Tulsa, Okla., 70 percent of patients with myofascial pain in the back and extremities who received botulinum injections over a two-year period reported “good” (15.5 percent) to excellent(54.5 percent) pain relief lasting an average of 2.5 to 3.6 months. Ten percent were pain-free after one year.
Pitting Pain with Poison?
Need Help Keeping Track of Your Injections? Download our Tracking Toxin Form listed below.
Need Help Comparing the Side-effects of botulinum toxin ? Download our Toxin Side-Effect Chart listed below.
MyoBloc : http://www.solsticeneuro.com
Botox : http://www.BotoxMedical.com
For information about the new upcoming N201 Neurotoxin Trials, go to our Nt201 webpage. This is the new Xeonim Toxin by Merz, Inc.
New information about the upcoming PurTox by Mentor Corp. is to be released as they plan on branching out from the cosmetic arena to the Cervical dystonia arena in 2008-9. More news to follow.
A new purified form of Botulinum Toxn, made by Allergan , will be undergoing clinical trials in 2010.

Botulinum Toxin Side-effect Chart

Report on toxin side-effects
Toxin Chart (pdf format)

Keeping Track of Botulinum Toxin Injections

A monitoring sheet for toxin injection sessions ( dosing, units, side-effects etc. )
Tracking Toxin Effects (pdf format )

More Detailed Information about Botulinum Toxin :

Clinical Applications for Botulinum Toxin Type A in Pediatric Patients While much attention has been paid to the cosmetic application of botulinum toxin type A recently, there are a number of other valuable uses for this agent. Journal Article, Pediatr Pharm, March 2003
The Botulinum Toxins in the Treatment of Cervical Dystonia The use of botulinum toxin to treat cervical dystonia (CD) has dramatically improved the quality of life of patients with this disabling, often painful disease. Journal Article, Semin Neurol, March 2001.
Unlabeled Uses of Botulinum Toxins: A Review, Part 2 Efficacy and safety data regarding the unlabeled uses of botulinum toxins are reviewed, and the pharmacology, adverse effects, and more. Journal Article, Am J Health-Syst Pharm, February 2006.
Unlabeled Uses of Botulinum Toxins: A Review, Part 1. Although these toxins are generally well tolerated, the risks and benefits should be weighed for each patient before they are used for unlabeled indications. Journal Article, Am J Health-Syst Pharm, January 2005.
Botulinum toxin type A versus botulinum toxin type B for cervical dystonia Botulinum toxin type A versus botulinum toxin type B for cervical dystonia. Cochrane Rev Abstract, April 2007.
Most recent information on ” Pain and Cervical Dystonia ” at www.medscape.com : http://www.medscape.com/viewprogram/7692