Botulinum toxin is an incredibly potent neurotoxin. Popularly sold under the brand name Botox, in 2001 over one million patients were treated in the United States. Sales in the United States exceeded $300 million in 2001. Botox is the most popular medical cosmetic treatment in the UK.¹

Despite its popularity, for most people Botox simply refers to a method of medical cosmetics; removing 'crows feet' and 'frown lines' from properly aged faces. More often used as a punchline than referred to as medical treatment, Botox has a strange place in the public's eye. Even more interesting are the remarkable uses for this deadly neurotoxin.

What is botulinum toxin?

Bacteria of the species Clostridium botulinum produce seven forms of neurotoxin²³. The toxins are among the most potent, most poisonous substances in the world. These neurotoxins (in fact, all neurotoxins) attach themselves to nerve endings. There are many different kinds of nerves, but the botulinum toxin attaches to nerves that control muscles ⁴. In this binding botulinum toxin prevents the nerve from sending its chemical signal to the muscle, preventing the muscle from contracting⁵.

What are the potential uses of botulinum toxin?

If this toxin is so poisonous how could it help? There are three major uses for botulinum toxin:

1. diseases of too much muscle contraction
2. diseases of excessive glandular secretion, specifically drooling and sweating
3. medical cosmetics, also known as 'cosmesis'

Too much muscle contraction can happen after a stroke, brain or spinal cord injury. Similar injuries with excessive muscle spasm can also be the result of cerebral palsy or genetic diseases of nerves. These conditions cause significant physical limitations as well as profound pain. As an example of how contraction may hurt, flex your hand into a fist as hard as you possible can. Now hold it as long as you can, as tight as you can. Keep squeezing harder and harder. After only a few seconds the pain may begin. Moreover, the clenched hand is limited in function compared to the relaxed hand.

Any muscle can be affected by spasm, regardless of muscle size or location. This would include the muscles of the voice box and the eyes. Botulinum toxin treatment is indicated for several voice box and eye disorders, specifically spasmodic dysphonia, strabismus and blepharospasm. Symptoms of these conditions include speech difficulty, poorly coordinated eye movements and eyelid tremor.

Diseases of muscle spasm are surprisingly common. They can be tremendously painful and debilitating. Relaxation of the muscles in spasm can be performed several ways mechanically, chemically or surgically. Botulinum toxin is one of these treatments. However, before chemical or surgical interventions are used, physical therapy is often employed to see if muscle can be stretched into relaxation. In addition, there are many other methods of relaxing these muscles that are not widely used in traditional medical practice⁶.

Excessive sweating and drooling are also conditions that can be addressed by botulinum toxin treatment. Botulinum toxin injections reduce the release and production of secretions from the parotid and axillary glands (which produce saliva and armpit sweat). Because of the risk of the procedure, it is recommended that patients exhaust other options first.

Cosmesis, or medical cosmetic treatment, is popular for reducing lines on the face caused by muscle contraction⁷. The relaxation of frequently used facial muscles (in very focused areas) will reduce the wrinkling of skin. These areas typically include the forehead, the skin near the edge of the eye and the skin near the edge of the mouth. When used in broader areas, the effect will temporarily reduce facial expression. The prinicples behind this form of treatment are the same as those used in larger muscles.

What are the dangers of botulinum toxin?

Contracting our muscles is certainly something we benefit from, especially the muscles of the digestive tract, the heart and the diaphragm (which allows us to breathe). If botulinum toxin were to affect these muscles, they would not contract or contract improperly. Illness of this kind is called botulism. Botulism poisoning can occur from canned foods or poorly smoked meats or fish that have been contaminated with Clostridium botulinum or its spores. Tragically, this can also affect infants (but not older children or adults) who ingest contaminated honey⁸. Botulism can cause terrific gastrointestinal distress, changes in heart rhythm and paralysis of the muscles of respiration.

What are the other concerns regarding botulinum toxin treatment?

As with all medicines that are injected by needle there are several general concerns: allergy to the medicine, infection of the skin where the needle was inserted and bleeding or damage to tissue by the needle. Botulinum toxin has other concerns as well. Injecting this drug into the bloodstream can be deadly. Proper technique is essential to avoid this. Thankfully, proper technique is also very easy. Few, if any, injuries have been reported because of this.

One area of concern is the length of time the medicine will work. The toxin binds to the nerve ending permanently. However, the nerve will generate a new branch to the muscle and eventually start the muscle contraction again. The effect of botulinum toxin can begin in 7 to 10 days and last from 6 weeks to greater than a year, but the generally reported time of benefit is 3 to 4 months. Thus, repeated treatment is typical. There is a risk of the body becoming used to the botulinum toxin and generating antibodies to it, thus prevent it from working. Because of this risk, most doctors recommend distancing botulinum toxin treatments as far apart as possible and using as little medicine as is effective. Drug companies continue to search for the other toxins (Botulinum toxin A and B are used today) in an effort to avoid this antibody formation.

Another area of concern is cost. Pharmaceutical companies use high standards for the safety and purification of botulium toxin. Because of the incredible potency of the drug, its purity is quite important. This process is extremely costly. In the midwestern U.S. a 100 unit supply of BoTox can cost $500 to the physician. 100 units may treat one large muscle in the arm or may treat two facial muscles for ten different patients. The size of the muscle contributes to he dosage required to treat. No more than 400 units should be employed in a single patient in a single treatment (to minimize the risk of antibody formation), although some practitioners are using as much as 800-900 units for patients with extensive muscle spasm.

Another risk to consider concerns Botox's cosmetic applications. Patients may find that they do not like their appearance after Botox injection. Extensive facial relaxation may cause loss of expression. The loss of expression creates a mask-like appearance. This is more likely to occur when larger areas are treated at one time.

Botox, useful in many ways

Despite the popular perception of Botox as a form of medical cosmetics (like face lifts and tummy tucks), there are many practical applications for this medicine: preventing pain from affecting patients, keeping children with cerebral palsy walking, allowing stroke patients to use their hands. Cosmesis helps many feel better about themselves; while the benefits of reduced spasticity may allow patients to live fuller lives.