The biggest study into the treatment of urinary incontinence with botulinum toxin (trade name Botox) has demonstrated that it is effective in treating overactive bladder (OAB) -- a debilitating common condition which can affect up to 20% of people over the age of 40.
The study from the University of Leicester was led by Dr. Douglas Tincello, Senior Lecturer at the University and Honorary Consultant Gynaecologist at University Hospitals of Leicester NHS Trust.
Dr Tincello, of the University of Leicester's Department of Cancer Studies and Molecular Medicine, has published his research in the journal European Urology. The research was funded by the Moulton Charitable Trust, Wellbeing of Women and the Rosetrees Trust.
OAB is a form of urinary incontinence with symptoms including having to rush to the toilet, nocturia (the need to interrupt sleep at night to urinate) and having wetting accidents before reaching the toilet. In general, urinary incontinence is more common in women and can be an excruciatingly embarrassing condition that can majorly affect a person's daily life.
OAB is usually caused by the bladder muscle being overactive and contracting at random moments, rather than only when it is convenient to empty the bladder. This is called detrusor overactivity or DO. At the moment, treatment is usually started with pelvic floor muscle exercises, advice on fluid intake and one of a range of tablets. While these measures work for some people, a large number of patients gain no relief or have bad side effects.
The four year study involved 240 women with severe DO who had failed to get better after two different drug treatments.
Dr Tincello said: "We found that a single treatment with botulinum toxin was a very effective treatment for the symptoms of DO; patients were able to pass water one or two times less often during the day, and also noticed far fewer times when they had bad feelings of urgency and had to rush to the bathroom.
"In patients treated with botulinum toxin the times of urgency dropped from six a day to less than one a day. Most excitingly, about 4 in 10 women become completely continent again after six weeks and a third were still continent again six months after treatment. The effects to start to wear off after about six months or so.
"The treatment is not without complications; about 1 in 8 women had some difficulty emptying their bladder at some time in the six months after treatment (due to paralysis of the bladder muscle). This was treated by teaching the women to use disposable catheters, but the effect does wear off after about six months on average."
In 2006, when the study started, it was the only clinical trial of botulinum toxin in women with DO, and it is the biggest study of its kind, providing a large body of evidence detailing how effective and safe botulinum toxin treatment is.
Dr Tincello said: "These findings are important because many doctors have been offering this treatment to patients based on the information from previous studies in people with spinal injuries, and now we have accurate information on exactly what benefit is likely to be noticed after treatment and how common the side effects will be. This will allow patients to decide whether they wish to have this treatment, which at the moment is not licensed for treating DO and OAB.
"I am very excited by our work; this bladder condition is very frustrating for me as a doctor, and botulinum toxin works so much better than the drugs we have. My patients have been delighted with how well it works, even with the chance of needing to use a catheter. Our study is the largest one completed without any involvement from the companies who make the drug and it is very satisfying to have contributed to finding out how effective the drug is."
Dr Tincello added that the research shows that botulinum toxin is a very effective treatment which provides a long period of benefit from a single treatment, albeit with some side effects.
The team is currently doing some further work on the data from this study to find out how cost-effective botulinum toxin is likely to be.
"Since the effect of the treatment is so much greater than a six month course of tablets, our work may lead to botulinum toxin being used much more widely for this bladder condition and it may turn out be cheaper too," said Dr Tincello.
- Douglas G. Tincello, Sara Kenyon, Keith R. Abrams, Christopher Mayne, Philip Toozs-Hobson, David Taylor, Mark Slack. Botulinum Toxin A Versus Placebo for Refractory Detrusor Overactivity in Women: A Randomised Blinded Placebo-Controlled Trial of 240 Women (the RELAX Study). European Urology, 2012; DOI: 10.1016/j.eururo.2011.12.056
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