Dec. 5, 2005 -- A drug that has the same active ingredient as Botox cuts pain from tennis elbow, according to researchers in Hong Kong.
The usual treatment options for tennis elbow include use of anti-inflammatory medications, physical therapy, and localized steroid injections. For severe or unrelenting cases, surgery may be necessary.
The study was small and mainly included women who had had "tennis elbow" pain for several months. More studies are needed to see if the drug helps other patients, write the researchers.
They included Shiu Man Wong, MBBCh, of the medicine department at Hong Kong's North District Hospital.
The study appears in the Annals of Internal Medicine.
Wong's study included 60 people. Participants got injections near their elbows. They were asked to avoid motions that trigger symptoms of tennis elbow for two days after getting the shots. They were also told not to get any other treatments for tennis elbow during the study.
Some patients got shots of a Botox-like drug called Dysport. For comparison, others got placebo injections of saline solution (salt water) with no medicine.
Botox itself wasn't tested. Dysport, like Botox, contains botulinum toxin.
Dysport was developed in the U.K. in the early 1990s to treat several neurological and eye-related conditions; it's also used to treat facial wrinkles and other conditions, according to Dysport's web site.
Less Pain Reported
Participants rated their pain three times: at the study's start, four weeks later, and 12 weeks later. Their grips were also tested at the same time.
Those in the Dysport group reported a drop in pain by the study's fourth week. After 12 weeks, they still had less pain than those who had gotten the shots of saline.
Patients hadn't been told which drug they'd gotten. Some may have guessed, the researchers note.
Botulinum toxin can weaken muscles in or near the injection area, states a journal editorial.
In Wong's study, the drug didn't weaken patients' grip. However, more patients who got Dysport reported mild weakness in the fingers of their affected arm.
Four weeks after their shot, 10 Dysport patients reported mild finger weakness in the hand at the end of the treated arm. Two still had the problem at the end of the study. Finger weakness interfered with one patient's work, the researchers report.
Six people who got the saline shots reported the same problem in the study's fourth week. One of those cases lasted for the rest of the study.
The frequency, severity, and duration of the drug's side effects need further study, the researchers write.
How Does It Work?
Wong's team doesn't know how botulinum toxin eases pain.
They mention that in another study by other researchers, botulinum toxin shots didn't work better than a placebo in patients with tennis elbow.
Those patients had milder symptoms and their shots were placed a bit farther from the elbow, Wong's team notes.
In an editorial, Seth Pullman, MD, notes an expanding list of uses for drugs containing botulinum toxin. He calls the use of botulinum toxin to treat pain "intriguing."
Pullman works at Columbia University Medical Center. He didn't work on Wong's study.