Early effect on the overactive bladder symptoms following botulinum neurotoxin type A injections for detrusor overactivity

OBJECTIVES: Limited studies to date have reported on the onset of effect of intradetrusor botulinum neurotoxin type A (BoNTA) injections when used to treat the symptoms of the overactive bladder (OAB). Furthermore, few studies have examined the effect of BoNTA on urgency and nocturia, now recognised as the most bothersome symptoms of the OAB syndrome. We studied the immediate effect of BoNTA on the OAB symptoms by recording the daily changes during the week after treatment of patients with neurogenic or idiopathic detrusor overactivity (NDO/IDO). METHODS: Twenty-four patients (16 NDO, 8 IDO) treated with 300mu BOTOX((R)) (NDO) or 200mu (IDO) completed a 4-d voiding diary before and 4 wk after treatment and a 7-d diary starting the day immediately after injections. Data were analysed for intragroup daily changes during the first week and for further changes at 4 wk. Parametric t tests were used for statistical analysis (significance at p<0.05). RESULTS: The two groups were comparable at baseline for all studied variables. In NDO, significant improvements in urgency, frequency, and nocturia were seen at day 2 post injection and in incontinence at day 3, and were sustained at 4 wk. In IDO, the first significant change in urgency, frequency, and incontinence was seen at day 4, with urgency showing the most consistent changes thereafter. All parameters significantly improved at 4 wk. CONCLUSIONS: Intradetrusor BoNTA ameliorates all OAB symptoms within the first week after treatment, but urgency is most rapidly and consistently affected, suggesting an early effect on bladder afferent pathways. Differences in the toxin dose or possibly underlying pathophysiology may account for an earlier trend for symptomatic improvement in the NDO patients.