The effects of botulinum toxin A on patients with idiopathic detrusor overactivity. A double-blind, randomised, placebo-controlled trial.

INTERVENTION: Baseline: voiding diary, urodynamics, quality of life (QoL) questionnaires. Flexible cystoscopy and 3 bladder biopsies followed by injection of either 200 u of botulinum toxin A (20 injections at 10 u/ml/site) versus placebo (normal saline 20 injections at 1 ml/site. Follow‐up: At 4 and 12 weeks: urodynamics, voiding diary, flexible cystoscopy and 3 bladder biopsies, QoL questionnaires. At 3 months patients are unblinded. Those that received placebo will be offered Botulinum toxin treatment. Follow‐up will be extended to confirm longevity of treatment. A further follow‐up time point of 6 months will be instigated collecting the same data as at 4 and 12 weeks. CONDITION: Overactive bladder symptoms and idiopathic detrusor overactivity. ; Urological and Genital Diseases ; Other disorders of bladder PRIMARY OUTCOME: 1. Urinary frequency/24 hours; 2. Maximum cystometric capacity SECONDARY OUTCOME: 1. Urinary urgency/24 hours; 2. Urge incontinence/24 hours; 3. QoL: 3 validated QoL questionnaires (KHQ, UDI6, IIQ7); 4. Urodynamic variables:; 4.1. time to first invluntary detrusor contraction; 4.2. maximum detrusor pressure on filling/voiding; 4.3. post void residual INCLUSION CRITERIA: 1. Refractory to traditional anticholinergic therapy either due to poor efficacy or side effects 2. Proven detrusor overactivity on urodynamic studies 3. Detrusor overactivity of non‐neurogenic origin