Botulinum Toxin Health Article

Definition

Botulinum toxin is the purified form of a poison created by the bacterium Clostridium botulinum. These bacteria grow in improperly canned food and cause botulism poisoning. Minute amounts of the purified form can be injected into muscles to prevent them from contracting; it is used in this way to treat a wide variety of disorders and cosmetic conditions.

Purpose

Botulinum toxin was developed to treat strabismus (cross-eye or lazy eye), and was shortly thereafter discovered to be highly effective for many forms of dystonia. Spasticity can also be effectively treated with botulinum toxin. Injected into selected small muscles of the face, it can reduce wrinkling. Other conditions treated with botulinum toxin include:

• achalasia
• anismus
• back pain
• bruxism
• excess saliva production
• eyelid spasm
• headache
• hemifacial spasm
• hyperhidrosis
• migraine
• palatal myoclonus
• spastic bladder
• stuttering
• tics
• tremor
• uncontrollable eye blinking
• vaginismus

It is important to note that as of early 2004, the only Food and Drug Administration-approved uses for botulinum toxin are for certain forms of dystonia, hemifacial spasm, strabismus, blepharospasm (eyelid spasms), and certain types of facial wrinkles. While there is general recognition that certain other conditions can be effectively treated with botulinum toxin, other uses, including for headache or migraine, are considered experimental.

Description

A solution of botulinum toxin is injected into the overactive muscle. The toxin is taken up by nerve endings at the junction between nerve and muscle. Once inside the cell, the toxin divides a protein. The normal job of this protein is to help the nerve release a chemical, a neurotransmitter, which stimulates the muscle to contract. When botulinum toxin divides the protein, the nerve cannot release the neurotransmitter, and the muscle cannot contract as forcefully.

The effects of botulinum toxin begin to be felt several days after the injection. They reach their peak usually within two weeks, and then gradually fade over the next 2–3 months. Since the effects of the toxin disappear after several months, reinjection is necessary for continued muscle relaxation.