Intravesical instillation of oxybutynin hydrochloride therapy for patients with a neuropathic bladder

Intravesical oxybutynin hydrochloride was administered to 17 patients with a neuropathic bladder (myelomeningocele in 15 and spinal cord tumour in two) and urinary incontinence refractory to intermittent catheterisation. Therapy consisted of instillation of a 10 ml solution containing 5 mg oxybutynin hydrochloride twice daily. The cystometric bladder capacity before and after 1 hour of intravesical oxybutynin hydrochloride was 132 +/- 45 ml and 193 +/- 71 ml (mean +/- 1 standard deviation, p < 0.01) in all 17 patients. In 13 patients with low compliant bladders, the mean bladder compliance before and after 1 hour of instillation was 4.2 +/- 2.4 ml/cmH2O and 8.5 +/- 6.4 ml/cmH2O respectively (p < 0.01). The period of the intravesical oxybutynin hydrochloride treatment ranged from 2 to 16 months (mean 11.1 months). The improvement rate of 'moderately improved' and better response was 76.5% in all 17 patients. One patient complained of slight lower abdominal pain, which receded as treatment continued. Since the pH value of the solution appeared to be so low as to irritate the vesical mucosa, the value was adjusted to 5.85. No local or systemic side effects were observed thereafter. These encouraging results suggest that intravesical instillation of oxybutynin hydrochloride is an attractive alternative in patients with a neuropathic bladder, who are either unresponsive to or have intolerable side effects from oral medications.