Oct. 12, 2001 ST. LOUIS - Tension headaches send most people to the medicine cabinet in search of relief, but many of the drugs they grab provide only a brief respite from the pain. A new study by researchers at Saint Louis University School of Medicine, however, suggests that long-term relief is now possible with small doses of botulinum toxin (botox).
The researchers found that small doses of botulinum toxin Type A effectively relaxed the muscles involved in triggering and/or perpetuating tension headache pain. The study found that the injections reduced the frequency of tension headaches for a majority of patients for up to three months and slightly reduced the intensity of the headaches.
Christina Burch, M.D., primary investigator and assistant professor in the division of neurology at Saint Louis University School of Medicine, presented the findings at the Tenth Congress of the International Headache Society in New York.
"Botulinum toxin Type A represents a new approach to the management of frontal tension headaches," Dr. Burch said. "It allows therapy to be targeted to specific problem muscles, which isn't possible with existing medication, such as over-the-counter aspirin or acetaminophen."
More than 78 percent of Americans suffer from chronic or a bout of tension headaches in their lifetime. Tension headaches are distinct from migraine headaches or headaches triggered by lack of food, sleep, head trauma or allergies/sinusitis. Tension headaches are characterized by a sensation of painful tightness around the head, which can be worse in some areas than others. For people whose pain is predominately in the front, furrowing the brow can become habitual and worsen the symptoms. Forty-four percent of those who suffer from tension headaches say the pain can become strong enough to limit their ability to function.
To conduct the study on botox Type A, Dr. Burch and her colleagues treated 41 patients who had at least two frontal tension headaches a week. The study was randomized so that some patients received the botox injections and others received a placebo. Treatment consisted of an office visit during which patients received eight low-dose injections of botox Type A along the frontalis complex-the area of the forehead between the eyebrow and the hairline-in order to relax the muscles. The continuous contraction of these muscles contributes to the pain associated with a tension headache.
After treatment, patients in both the botox and placebo groups reported fewer headaches than before they began the study, but the frequency was even lower for the botox patients. Furthermore, patients in the botox group reported significantly lower headache intensity ratings. In addition, patients in the botox group reported that their headache symptoms were easier to control. Dr. Burch and her colleagues found that one botox Type A treatment lasted three months or more.
Dr. Burch said people with tension headaches tend to overmedicate by swallowing a pill whenever they feel the pain coming on. Mild overdoses over time can result in liver damage, stomach problems and bleeding. "That's why it's good to have an alternative," Dr. Burch said.
Botulinum toxin is a natural substance secreted by the bacterium that causes botulism. Its beneficial aspects were discovered by accident. Researchers working on a vaccine for botulism injected the toxin into muscle tissue and found that the toxin stayed where it was placed. It did not travel into the bloodstream or cause symptoms of botulism and it appeared to relax muscles in the area injected.
Botox has been used successfully to help stroke and cerebral palsy patients regain muscle control. Physicians also are using botox to relax the vocal cords of patients with speech impairments and to ward off facial wrinkles. In western Europe botox is commonly used for treating tension headaches.
Dr. Burch said that one of the drawbacks of using botox, however, is that because it is a natural substance the human body eventually develops immunity to it. Some patients may respond to botox for years while it loses its effectiveness in others more quickly.
"It's still very promising," said Dr. Burch. "The patients in our study felt they had control over something that had been out of their control for years and given science, it won't be long before we figure out a way around the immunity issue."
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first M.D. degree west of the Mississippi River. Saint Louis University School of Medicine is a pioneer in geriatric medicine, organ transplantation, chronic disease prevention, cardiovascular disease, neurosciences and vaccine research, among others. The School of Medicine trains physicians and biomedical scientists, conducts medical research, and provides health services on a local, national and international level.
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