To examine the efficacy and tolerability of tizanidine for the treatment of dysfunctional voiding in children compared with those of doxazosin.

A total of 40 children with dysfunctional voiding were enrolled in a prospective, randomized, 2-parallel group, flexible-dose study. The evaluations were performed in accordance with the International Children's Continence Society guidelines. The children were followed up after 1 week and then monthly for 6 months for the clinical, urine culture, and urodynamic parameters. The degree of improvement was assessed using a satisfaction scale that ranged from 0 (no improvement at all) to 10 (total improvement).

A total of 40 patients with a mean ± SD age of 7 ± 2.6 years were enrolled. The clinical and urodynamic parameters were comparable between both groups. At the last follow-up visit, both groups had had similar improvement in the severity of symptoms, satisfaction scale, and noninvasive flowmetry parameters. In the doxazosin group, urge episodes was the only symptom that showed a significant reduction compared with the baseline values (P = .028). However, the incidence of nocturnal enuresis, urgency attacks, and daytime incontinence were significantly reduced compared with baseline in the tizanidine group (P = .003, P = .008, and P = .017, respectively). Adverse effects were recorded in 6 patients (15%). Epigasteric pain was reported in 2 children (10%) who received doxazosin. In the tizanidine group, a loss of appetite was noted in 2 children (10%), epigastric pain in 1 (5%), and headache in 1 (5%).

Tizanidine could be a safe and effective treatment of children with dysfunctional voiding due to pelvic floor/skeletal sphincter dysfunction. More placebo-controlled trails with larger sample sizes are needed.