13th March 2012 - A study has found that injecting botulinum toxin A (Botox) into the wall of the bladder is an effective way of treating a debilitating condition in which people have a sudden urge to pass urine.
Overactive bladder affects up to 20% of people - mainly women - over the age of 40. It is a type of urinary problem whose other symptoms include having to go often (frequency), the need to get up in the night to use the bathroom (nocturia), and wetting accidents before reaching the toilet (incontinence).
As the name suggests, overactive bladder (OAB) is usually caused by the bladder muscle being overactive and contracting inappropriately, rather than only when it is necessary or convenient to empty the bladder. This is called detrusor overactivity, or DO.
Current treatments include 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 little or no relief or have bad side-effects.
In the largest study into the effects of botulinum toxin on urinary incontinence, British researchers recruited 240 women with severe DO who had failed to get better after treatment with two different types of medication. Around half the women were given botulinum injections, while the remainder received a saline placebo - an inactive salt solution.
Those treated with botulinum saw the number of times that they needed to urinate fall from six a day to less than one a day. The researchers say that about a third of women in the botulinum group (31.3%) developed bladder control - or continence - after being treated, compared with 12% in the placebo group.
They also noted that the effects of the treatment started to wear off after about six months or so.
Lead researcher Dr Douglas Tincello, a senior lecturer at the University of Leicester and a consultant gynaecologist, says the treatment is administered via a flexible camera known as a cystoscope and an injection needle. "The camera is passed into the bladder via the urethra - where you urinate from - and the botulinum is injected in 10 to 20 places in the bladder," he tells BootsWebMD. "It can be uncomfortable, but only takes about three minutes, so all my patients have tolerated it."
However, there were also a number of side effects associated with the treatment. Around a third of women injected with botulinum developed urinary tract infection, compared with 10% among those given the saline solution.
Also, those given botulinum reported greater difficulty emptying their bladders. 16% of those in the botulinum group experienced this paralysis of the bladder muscles, compared to 4% of those in the placebo group. "Although the risk of paralysis causing problems emptying the bladder was common, the women in whom it occurred still thought the benefits were worth it," says Dr Tincello. He adds: "Managing emptying problems can be done with disposable catheters which can be done discreetly [by the patients themselves (self-catheterisation)], and the women were still able to enjoy the benefits of reduced symptoms and a return to continence."
The study is published in the journal European Urology with backing from the Moulton Charitable Trust, Wellbeing of Women and the Rosetrees Trust.
To provide even greater transparency and choice, we are working on a number of other cookie-related enhancements. More information