WASHINGTON, Nov. 13 -- Botox, best known for ironing out aging wrinkles, may also relieve severe pain from osteoarthritis of the knee, a researcher reported here.
In interim data from a randomized placebo-controlled trial, injections of botulinum toxin type A significantly reduced severe pain and improved function, according to Maren Mahowald, M.D., of Minneapolis VA Medical Center.
"We're very excited," Dr. Mahowald said before she presented her data at the American College of Rheumatology meeting here.
The trial, Dr. Mahowald said, grew out of clinical observations in conditions such as painful spasticity, in which investigators noticed that pain often lessened before a decline in muscle contractions.
"This suggested an independent analgesic effect of botulinum toxin," she said. So she and colleagues conducted an open-label study, in which they found 10 of 15 patients had an improvement in pain of 50% or greater.