Botulinum Toxin A vs Anticholinergic Treatment of Neurogenic Overactive Bladder in Patients With Multiple Sclerosis

Botulinum toxin type A injections into the detrusor at a dose of 200 units (U) of BOTOX® are a recognized second-line treatment for the treatment of adult neurogenic lower urinary tract disorders. Anticholinergics are established as the usual first-line treatment for neurogenic detrusor hyperactivity, but are oft not sufficiently effective and have significant side effects. In patients with multiple sclerosis (MS) suffering from overactive bladder, the 200 U dose of BOTOX® is very effective but induces a risk of urinary retention in 30% of patients requiring the temporary use of self-catheterization1. At 100 U, a recent study shows the efficacy and very good tolerance of botulinum toxin A in terms of probing risk in MS patients with overactive bladder and failure of anticholinergics. Furthermore, the efficacy of anticholinergics in MS has been little studied and is also disputed. The investigators plan to test the therapeutic alternative as the first line of treatment in two groups of randomized MS patients from a homogeneous population suffering from overactive bladder: * a group testing the effectiveness of low doses of botulinum toxin type A (100 U, BOTOX®), * the other group receiving the standard anticholinergic treatment (solifenacin succinate, Vesicare®). During this pilot study, the efficacy and side effects profile of each treatment will be analyzed in order to determine the amplitudes of effect and the safety profiles in this population and in order to establish the statistical hypotheses for a subsequent randomized multicenter study. The aim of this study will be to establish the benefit of botulinum toxin at a dose of 100 U as a first-line treatment instead of anticholinergics