Oxybutynin in the treatment of early detrusor instability after transurethral resection of the prostate

Objective To evaluate the symptomatic and urodynamic effects of oxybutynin in the control of irritative micturitional symptoms during the first week after transurethral resection of benign prostatic hyperplasia (BPH). Patients and methods Fifty-three patients (median age 67 years, interquartile range 62-72) were included prospectively in a double-blind placebo-controlled study, Pre-operatively, uroflowmetry and cystometrography (CMG) were performed, and the post-void residual volume (PVR) measured; symptoms were rated according to the Boyarski score. CMG was repeated on the first post-operative day and medication was started on the third day, Before withdrawing the catheter on the fifth day, CMG was repeated. Three days later, symptoms were evaluated according to the Boyarski score and uroflowmetry and the estimate of PVR reassessed. Results In comparison with placebo, oxybutynin significantly decreased frequency, urgency and detrusor pressure at first sensation of filling. However, oxybutynin did not lower the rate of pre-operative detrusor instability and exerted no effect on the maximal capacity of the bladder and corresponding detrusor pressure, Dryness of mouth was reported in 13% and 65% of patients receiving placebo and oxybutynin, respectively. Conclusion Oxybutynin alleviates early irritative symptoms after transurethral resection of BPH, without consistently modifying bladder urodynamics.