The news came out at this week's annual meeting of the American Urological Association in Anaheim, Calif.
For years, some urologists have used Botox off-label (meaning used for conditions not approved for by the FDA), says Michael Chancellor, M.D., professor of urology and obstetrics and gynecology at the University of Pittsburgh and one of the researchers involved in this week's presentations. The percentage of U.S. doctors using it currently is small, he says.
"I've used it since 1998 for both bladder problems and prostate problems," Chancellor tells WebMD.
For bladder problems such as overactive bladder, the Botox generally last about six months, he says; for prostate-related bladder problems, about a year.
After a few weeks, Chancellor says, some patients can stop the medications originally prescribed to relieve the bladder symptoms.
Injecting Botox into the prostate gland helped ease urinary symptoms for up to a year, says Yao-Chi Chuang, M.D., a urologist at Chang Gung Memorial Hospital in Taiwan and researcher for the study presented Wednesday at the conference.
Chuang, Chancellor and their team studied 37 men (average age 67) who did not do well on the medications commonly prescribed to help relieve the urinary problems associated with an enlarged prostate, a condition called benign prostatic hyperplasia, or BPH. The prostate gland surrounds the urine-carrying tube or urethra. When it enlarges too much, as it tends to do with age, it can constrict the urethra, and men report trouble emptying the bladder completely.
Common symptoms of BPH include weak urine stream, leaking or dribbling, feeling that the bladder hasn't emptied completely after voiding, and more frequent urination.
Using a needle about six inches long, Chuang's team injected 100 units to 200 units of Botox into each side of the prostate surrounding the urethra. The total amount injected depended on the size of the man's prostate, he says.
When the men were evaluated before and after treatment, Chuang found that 73 percent of the men had more than a 30 percent improvement in symptoms. "Effects lasted six to 12 months," he says. "It's very safe."
Exactly how it works isn't certain, Chuang says. "It probably relieves smooth muscle contractions of the prostate [that can contribute to the bladder problems], and inhibits the inflammatory process [that also plays a role]," Chuang tells WebMD.
The toxin may also help relieve symptoms of overactive bladder, in which the bladder wall muscle inappropriately contracts, causing the urge to urinate, other researchers reported.
Daniel M. Schmid, M.D., of the University Hospital Zurich, and his colleagues injected 100 units of Botox into the bladder wall muscle of 180 men and women with overactive bladder. Within two weeks, he reported, 87 percent had significant improvement in symptoms, with urgency disappearing in 75 percent and incontinence in 84 percent.
Chuang's Botox study was unfunded. Now, he is enrolling subjects in a study that will assign some men with BPH symptoms to a Botox group and others to a control group that will get placebo injections that don't contain Botox.
That study is funded by Allergan, the maker of Botox.
By Kathleen Doheny
Reviewed by Louise Chang, M.D.
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