Botulinum Toxin for Muscle Spasms

If stress or injury has your muscles in a bind, a shot of poison may relieve the stiffness.

Botox, or botulinum toxin, the poison produced from the bacteria that causes food poisoning, is now providing benefits for muscle pain when injected directly into the muscle itself.

Although the potentially paralyzing poison has also been used to smooth wrinkles and crow’s feet, doctors say it can also help relieve muscle stiffness.

The Drug Loosens Muscles

Since a car accident 13 years ago, Debra Smith’s chest, forearm and leg muscles didn’t work quite right. They were stiff and her movements painful and limited.

The answer for the 40-something Dallas woman, her doctor said, was the poison.

“It [the drug] makes the muscle a bit weaker,” says Dr. Susan Garstang, medical director of the inpatient rehabilitation unit at Parkland Hospital in Dallas, Texas. “We inject the botox into those muscles and it relaxes them so they can function.”

Botox works by loosening the muscle that is frozen in stiffness, according to Christine Cassiano, spokeswoman for Allergan, of Irvine Pharmaceuticals, the drug’s manufacturer. The drug acts to prevent the nerve ending connected to the muscle from contracting.

The drug works locally so it does not cause any other symptoms of poisoning.

Toxin First Isolated in 1897

Botulinum toxin was first identified in 1897 from the bacteria Clostridium botulinum, and in 1949 the U.S. federal government started researching it as a biological weapon, but stopped because it didn’t work. Clinical studies in humans began in 1981 to test its effectiveness in muscle disease.

Botox received Food and Drug Administration approval for uncontrollable blinking and crossed eyes in 1989. In December, the agency approved botox for the pain associated with cervical dystonia, a condition that severely affects head and neck shoulder muscles in 50,000 Americans.

Elan Pharmaceuticals, of Dublin, Ireland, has another FDA-approved version of botulinum toxin on the market, called Myobloc, for the treatment of cervical dystonia.

Botox currently is in clinical trials in the United States for pediatric cerebral palsy, spasticity associated with stroke, pain management and excessive sweating, according to Allergan’s Cassiano.

Doctors Use it Off Label

But doctors will often use it in what is called an off-label fashion, says Garstang. Physicians can use their professional discretion to prescribe a medication even if a drug is not approved for a certain condition.

In fact, Garstang used Botox in an off-label fashion for Smith.

Allergan has applied to the FDA for approval on Botox for brow furrows, but has no plans to apply for the treatment of crow’s feet.

Injections typically take effect in three days and last three months. Botox costs between $300 and $500 a shot, when insurance doesn’t cover it. Most people need to get continuous treatments.

Smith is hoping the toxin will help her bring movement back to her arms so she can grip her cane and to control her toe, which makes walking painful.

ABCNEWS’ Janet St. James of WFFA in Dallas and Robin Eisner of contributed to this report.