Botulinum Toxin—What Urologic Uses Does the Data Support?

Abstract

Botulinum toxin-A (BTX-A) is well established in the management of various aspects of lower urinary tract dysfunction (LUTD). One formulation, OnabotulinumtoxinA has recently been licensed in many parts of the world for use in neurogenic detrusor overactivity (NDO), and in the US for idiopathic overactive bladder (OAB), in patient's refractory to antimuscarinics. This review article looks at recent clinical publications that examine the use of BTX-A for the treatment of LUTD with a focus on OAB, detrusor overactivity (DO), benign prostatic hyperplasia (BPH) and Painful bladder syndrome / interstitial cystitis (PBS / IC). A literature review was conducted using the PubMed database and studies that were published within the time frame of January 2011 to present were included. Large randomised placebo controlled trials and a pooled analysis of patients with multiple sclerosis / spinal cord injury and NDO has suggested that BTX-A improved urinary incontinence (UI) episodes, urodynamic parameters and QoL in these patients. 200U of OnabotulinumtoxinA appeared equivalent to 300U. In patients with OAB, lower doses of 100U OnabotulinumtoxinA, appear efficacious and with an acceptable adverse event profile. In one large phase III trial, de novo clean intermittent catheterisation rates were 6.1%. Repeated injections in DO appear efficacious. Results from BPH studies are mixed, and the largest randomised study in this setting has shown significant improvements in a number of parameters for a variety of OnabotulinumtoxinA doses, but none of the doses were statistically better than placebo. Few studies have been conducted in PBS / IC and larger scale randomised placebo controlled trials are required to validate its use in this setting.