Double-blind crossover comparison of flavoxate and oxybutynin in women affected by urinary urge syndrome

Abstract

This double-blind multiclinic crossover study was performed in order to compare the efficacy and tolerance of a 4-week treatment course with flavoxate, given orally at 1200 mg/day, with that of oxybutynin, 15 mg/day orally, in women with idiopathic motor or sensory urgency. Fifty patients were included in the study: 41 (20 affected by sensory urgency and 21 by motor urgency) completed both courses of treatment and were evaluated for efficacy utilizing clinical and urodynamic criteria. Diurnal and nocturnal frequency, diurnal incontinence, urgency, dysuria, and daily utilization of pads were comparably reduced by both treatments. A statistically significant improvement in all urodynamic parameters was present at the end of both treatment courses. The effect on the urodynamic parameters of the two treatments was comparable. According to the patients, flavoxate cured or greatly improved the syndrome in 81.6% of cases, while oxybutynin produced the same effects in 78.9%. The difference in efficacy between the two treatments was not statistically significant. Of the 41 patients who received both treatment courses, 11 (26.8%) experienced adverse reactions with flavoxate, and 37 (90.2%) with oxybutynin treatment. Moreover, 5 patients, not included in the efficacy evaluation, interrupted the treatment because of side effects while taking oxybutynin, whereas no patients stopped while taking flavoxate. The severity of the side effects recorded during oxybutynin treatment was significantly greater than during treatment with flavoxate. Flavoxate showed comparable efficacy to oxybutynin in relieving the urge syndrome, but was associated with fewer and milder side effects.