Efficacy and safety of oxybutynin in children with detrusor hyperreflexia secondary to neurogenic bladder dysfunction

Purpose: We evaluated the efficacy and safety of oxybutynin in children with detrusor hyperreflexia due to neurological conditions. Materials and Methods: Study 1 - A prospective, open label trial of 3 formulations of oxybutynin (tablets, syrup and extended release tablets) was conducted for 24 weeks in children 6 to 15 years old with detrusor hyperreflexia who used oxybutynin and clean intermittent catheterization. The effect of treatment on average urine volume per catheterization and on secondary urodynamic outcomes was evaluated. Study 2 - The efficacy and safety of oxybutynin syrup were evaluated urodynamically in an open label study of children 1 to 5 years old with detrusor hyperreflexia who used oxybutynin and clean intermittent catheterization. Results: Study 1 - Mean urine volume per catheterization (± SEM) increased by 25.5 ± 5.9 ml (p <0.001). Maximal cystometric capacity increased by 75.4 ± 9.8 ml (p <0.001). Mean detrusor and intravesical pressures were significantly decreased by -9.2 ± 2.3 (p ≤ 0.001) and -7.5 ± 2.5 cm H₂O (p <0.004), respectively, at week 24. Of 61 children with uninhibited detrusor contractions 15 cm H₂O or greater at baseline 34 did not have them at week 24 (p <0.001). Improvements in bladder function were consistent across all oxybutynin formulations. Study 2 - Mean maximal cystometric capacity increased significantly by 71.5 ± 21.99 ml (p = 0.005). At study end only 12.5% of patients had uninhibited detrusor contractions 15 cm H₂O or greater compared with 68.8% at baseline (p = 0.004). Oxybutynin was well tolerated in both studies. There were no serious treatment related adverse events. Conclusions: All 3 formulations of oxybutynin are safe and effective in children with neurogenic bladder dysfunction.