NEW YORK (Reuters Health) - The results of a small study strongly suggest that botulinum toxin A (BTX-A) has an antinociceptive effect within the visceral pathways innervating the lowering urinary tract.

Although largely viewed as a cholinergic nerve specific toxin and used by urologists to treat disorders of muscle spasticity, "our results provide preliminary evidence that BTX-A may be a useful treatment option in patients with interstitial cystitis," which is characterized by urinary pain, frequency, and urgency, researchers note in the November issue of Urology.

Dr. Michael B. Chancellor, from the University of Pittsburgh school of Medicine and colleagues treated 13 women with recalcitrant interstitial cystitis (six in the United States and seven in Poland) with 100 to 200 units of Dysport (Polish patients) and Botox (US patients).

The medication was injected submucosally into 20 to 30 sites in the trigone and floor of the bladder while the women were under short general anesthesia or sedation.

Overall, 9 of 13 women (69%) saw improvement after treatment. Pain scores on the visual analog scale fell by 79% and symptoms of daytime frequency and nocturia fell by 44% and 45%, respectively.

Mean scores on the Interstitial Cystitis Symptom Index and Interstitial Cystitis Problem Index improved by 71% and 69%, respectively (p < 0.05).

Dr. Jeremy B. Tuttle, from the University of Virginia School of Medicine in Charlottesville, contends in an editorial that "if substantiated, these results imply our understanding of how BTX-A operates and how interstitial cystitis symptoms arise may need revision."

If BTX-A were operating only at cholinergic terminals, he explains, anticholinergic therapy would likely be effective in treating interstitial cystitis symptoms. "It seems likely that BTX-A is having additional effects on bladder innervation and/or has effects on the muscle itself," he writes.

Dr. Tuttle says Dr. Chancellor and colleagues "should be congratulated on producing a concise report of surprising results and for devising a new promising treatment" for interstitial cystitis.

Urology 2004;64:871-875

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