May 13, 2004
Injections of botulinum toxin A (Botox) can be helpful in addressing several types of bladder dysfunction problems, according to findings presented here at the 99th annual meeting of the American Urological Association.
"This is a safe and promising treatment for several types of lower urinary tract dysfunctions," Michael B. Chancellor, MD, said during his presentation. He noted that botulinum toxin A is effective for both skeletal and smooth muscle problems and that men and women respond equally to it. "Injections into the sphincter are associated with little risk of incontinence," he added. Dr. Chancellor is a professor of urology and gynecology at the University of Pittsburgh in Pennsylvania.
Dr. Chancellor and a coinvestigator reviewed the results of 110 patients with a variety of bladder disorders whom he had treated over the past six years with injections of botulinum toxin A into the bladder and urethra. The 35 men and 75 women ranged in age from 19 to 82 years old. Of these patients, 41 received injections into the bladder and 69 patients received injections in the urethra.
The disorders the patients suffered from included neurogenic detrusor hyperflexia, detrusor sphincter dysynergia, overactive bladder, benign prostatic hyperplasia, bladder neck obstruction, and interstitial cystitis. After receiving conscious sedation, the patients received either 100 to 200 units of botulinum toxin A in equal doses, injected into the four quadrants of the external sphincter, or 100 to 300 units of the drug injected into the bladder base. The drug was diluted with 10 to 30 mL of sterile saline. Twenty-seven patients have undergone up to six further injections, with between-treatment intervals of six months or less.
Dr. Chancellor noted that a patient will begin to experience maximal efficacy of the treatment within seven days of receiving treatment, and that he or she will continue to benefit from the injection for approximately six months. He said that he has observed no long-term complications, although one woman with multiple sclerosis who had bladder injection for detrusor hyperflexia experienced an increase in residual urine, from 78 mL to 125 mL. The same patient also had clinical improvement, though, and did not require catheterizations.
All patients who received injections into the bladder had preoperative evidence of involuntary detrusor contractions, which were confirmed by urodynamic testing. After treatment, the mean cystometric capacity increased from 124 mL to 265 mL. Seventy-four patients (67.2%) had either a decrease or absence of incontinence. Voiding diaries showed that they had fewer voiding symptoms in both the daytime and the nighttime, and patients' subjective global quality-of-life symptom scores also improved, Dr. Chancellor said.
Urologists will need to be aware of several issues when considering botulinum toxin A injections for bladder dysfunction, he added. First, repeat injections usually last longer than the first injection, with some patients maintaining efficacy for more than one year. Second, trigone injections have been associated with no clinical signs of vesicoureteral reflex or pyelonephritis. Finally, bladder injections are associated with greater efficacy than are urethral injections.
"The findings in this study are consistent with other reports showing that botulinum toxin injections are effective in treating overactive bladder," said Simon Hall, MD, in a telephone interview seeking outside comment. Dr. Hall chairs the department of urology at Mount Sinai Medical Center in New York City. "This treatment warrants further study in a controlled fashion, with an analysis by the various subgroups of bladder dysfunction."
AUA 99th Annual Meeting: Abstract 517. Presented May 10, 2004.
Reviewed by Gary D. Vogin, MD
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