Botulinum toxin therapy is the leading method in treatment of patients with neurogenic and non-neurogenic overactive bladder (OAB) that is refractory to anticholinergic drug therapy. A significant number of studies have been devoted to assessing the efficacy and safety of botulinum toxin therapy, but many questions about the use of onabototulinum toxin type A (BoNTA) remain unclear. One of such insufficiently studied questions is the long-term efficacy and tolerability of repetitive BoNTA injections in patients with non-neurogenic OAB. The aim of the study was to evaluate the results of repetitive BoNTA injections in the patients with non-neurogenic OAB.

The study included 117 women (an average age was 47.4±15.8 years) with refractory to anticholinergic drug therapy OAB syndrome. All patients underwent intravesical botulinum toxin therapy, the dose of BoNTA in all patients was 100 Units. The present study included women who had been suffering from OAB syndrome for at least 5 years and who received at least 2 intravesical BoNTA therapy courses. The maximum follow – up time was 56 months. The maximum and average number of intravesical injection courses performed was 7 and 4.1±1.4, respectively. The effectiveness of treatment was evaluated according to the data of voiding diaries, which patients had been filling in for 3 days monthly. Taking into account the possibility of developing urinary retention after BoNTA therapy, all patients were trained to perform bladder sterile self-catheterization prior the start of the treatment.

Among all observed patients, the efficacy of treatment was regarded as satisfactory in 109 (93.2%) patients and unsatisfactory in 8 (6.8%) patients. The duration of the botulinum therapy effect was estimated by the time interval between the BoNTA injection and OAB symptoms recurrence, which was deemed to be the reason for the next BoNTA injection. Average intervals between 2nd and 3rd, 3rd and 4th, 4th and 5th, 5th and 6th, 6th and 7th injections was 6.2±0.7 months, 6.5±0.5 months, 7.6±0.4 months, 7.9±0.4 months, 8.2±0.5 months, respectively.

A tendency to increase the duration of the effect from intravesical BoNTA injections with an increase in the number of procedures performed was observed. There were no cases of urinary retention after intravesical injections of BoNTA and not in a single case did the volume of residual urine exceed 200 ml.

The efficacy and safety of intravesical botulinum toxin therapy with its long-term repetitive use is not reduced. Quite the opposite, the duration of the treatment effect increases with each subsequent course of BoNTA injections.