Discontinuation rates and inter-injection interval for repeated intravesical botulinum toxin type A injections for detrusor overactivity

Objective To report discontinuation rates, inter‐injection interval and complication rates after repeated intravesical botulinum toxin type A for the treatment of detrusor overactivity. Method Patients with urodyamically proven detrusor overactivity who had two or more botulinum toxin type A injections in the period 2004–2011 at Freeman Hospital, Newcastle Upon Tyne, UK, were considered for the present study. Discontinuation rates, complication rates and interval between botulinum toxin type A treatments were retrospectively analyzed. Results Overall, 125 patients (median age 53 years, range 19–83 years) were included in the analysis. The female‐to‐male ratio was 2.4:1 and median follow up was 38 months. A total of 96 patients had idiopathic detrusor overactivity, whereas 29 had neurogenic detrusor overactivity. A total of 667 injections were carried out, with 125 patients receiving two injections, 60 receiving three injections, 28 receiving four injections, 14 receiving five injections, three receiving six injections, three receiving seven injections and two receiving eight injections. The mean interval (±standard deviation) between the first and second injection (n = 125) was 17.6 months (±10.4), between the second and third (n = 60) was 15.7 ± 7.4 months, between the third and fourth (n = 28) was 15.4 ± 8.6 months, and between the fourth and subsequent injections (n = 22) was 11.6 ± 4.5 months. A total of 26% required intermittent catheterization, and 18% developed recurrent urinary tract infections. There was a discontinuation rate of 25% at 60 months. Conclusion Repeated botulinum toxin type A injections represent a safe and effective method for managing patients with idiopathic detrusor overactivity and neurogenic detrusor overactivity. We have shown that the inter‐injection interval remains unchanged up to five injections.