Short‑term effects of oxybutynin dosage in individuals with neurogenic bladder following spinal cord injury: A retrospective cohort study.

The aim of the present study was to determine the relationship between dose of oxybutynin and reduction in detrusor pressure in individuals with neurogenic bladder (NGB) secondary to spinal cord injury (SCI). The hospital-based data were examined for all individuals with NGB and SCI who were admitted for urological evaluation between January 1999 and December 2016. Patient characteristics, urodynamics and bladder management details were collected at pre-treatment and post-treatment. The primary outcome used to assess oxybutynin treatment was the change in detrusor pressure (P). Analysis of covariance (ANCOVA) was used to investigate the relationship between dosage of oxybutynin and decrease in P. A total of 245 participants (112 who received no medication and 133 treated with oxybutynin) were included. After controlling for confounding factors, each 1 mg increase in oxybutynin was associated with a mean decrease of 0.9 cmHO in P (95% CI, -1.4 to -0.3). Stratifying bladder management by indwelling catheter, oxybutynin at a dose of 1 mg was associated with a mean decrease in P of 0.5 cmHO (95% CI, -1.4 to 0.4) in patients with indwelling catheters and 1.0 cmHO (95% CI, -1.7 to -0.3) in patients with clean intermittent catheterization and balanced bladder. This study provided guidance for setting the starting dose of drugs associated with response variability in NGB with SCI. Oxybutynin is deemed to be clinically effective for managing NGB in patients with SCI.