The ingredient in a Botox injection probably won’t help ease neck pain, nor will it help neck pain sufferers do physical activities any better or improve their quality of life, a new review of past studies suggests.

“The available evidence just suggests that it doesn’t work,” study author Dr. Paul Michael Peloso told Reuters Health. If patients have neck pain, “they and their physicians should be discussing other therapies,” Peloso added.

The ingredient in Botox, called botulinum toxin, is used to treat a range of conditions, including wrinkles, migraines, and excessive sweating. Botox is just one of several brand names for the drug, which is given through injections. None of the brands has been approved by the Food and Drug Administration to treat neck pain - but doctors may use the drug “off-label” for that purpose.

A recent report from the Institute of Medicine suggested that chronic pain, including neck pain, costs the United States more than $600 billion each year and affects about four in 10 adults (see Reuters story of June 29, 2011).

Peloso, the head of clinical research at the drug company Merck in Rahway, New Jersey, said doctors might consider using the Botox ingredient for neck pain after other more common treatments, including drugs like Tylenol and aspirin or exercises, haven’t worked.

Each injection typically costs a few hundred dollars, and patients may need repeat injections every few months for the drug to have a continued effect.

The new review analyzed the combined results of nine studies that tested botulinum toxin A - sold as Botox by Allergan - in people with new or chronic neck pain and related headaches.

Those studies compared the effect of botulinum toxin with drug-free sham injections or other pain treatments, using patient reports or doctor observations of pain, physical abilities, and quality of life. Altogether the studies involved 503 patients, including 272 who received injections of the drug.

Peloso and his colleagues noted that some of the studies had limitations - for example, it wasn’t clear how some had split the patients up into Botox and not-Botox groups, or researchers hadn’t kept treatment types hidden from patients or from those who measured their symptoms.

But taken together, the studies suggested Botox had done nothing to help relieve neck pain or related headaches, either alone or when added to exercise programs or other medications, when researchers reassessed patients at four weeks and six months after injections.

In addition, people given botulinum toxin were more likely to have a side effect, including soreness or flu-like symptoms, than those not given the drug.

The researchers concluded that almost all of the studies showed that any possible benefits were not worth the potential harms. Their findings are presented in the Cochrane Library, a publication of the Cochrane Collaboration, an international organization that evaluates medical research.

A company spokesperson told Reuters Health in an email that “Allergan does not have clinical programs evaluating the efficacy and safety of our botulinum toxin products in patients with sub acute or chronic neck pain,” but that Botox is indicated to treat “cervical dystonia,” in which neck muscles contract involuntarily, and neck pain linked to the condition. She also pointed out that the review didn’t focus only on Botox-brand treatments.

Peloso said that while some evidence suggests injections of steroids or anesthetics might help people with neck pain, the best pain-relief choice right now seems to be exercises that strengthen muscles and improve range of motion.

However, he pointed out, “The problem is as you would guess for exercise that it’s just not as simple as a one-time visit” or a daily drug - one reason his team was interested to see if Botox might have some benefit.

He said that companies have little incentive to study treatments for neck pain, which can be caused by anything from overuse of neck muscles to diseases such as arthritis and gets more common with age. Peloso added that his company does not make a Botox competitor, although it does market pain products that could be used for neck pain.

SOURCE: The Cochrane Library, online July 5, 2011.