[Medical treatment of bladder instability. Our experience]

To identify the factors that influence response to treatment of vesical instability.

A retrospective study was conducted to assess the efficacy of drug therapy with oxybutinin and imipramine in 89 patients with urodynamically demonstrated detrusor hyperreactivity. Control evaluations were performed at 2, 5 and 8 months. Evaluation of the results took into account the etiology, pressure and volume at which the wave of instability appeared.

The results were evaluated according to patient subjective criteria. We observed a positive response (cure and improvement) to treatment with oxybutinin alone or oxybutinin+imipramine in 66.25% of the cases; side effects were observed in 44%. There was a 20% improvement in the positive response rate when the wave intensity was greater than 55 cm H2O and the bladder volume at which this occurred was greater than 150 ml. No patient treated with second line drug therapy (flavoxate, nifedipine and trospium chloride) cured.

The etiology of vesical instability did not influence response to therapy. Waves with a greater intensity and those that appeared at higher volumes responded better to treatment. Nearly half of the patients with side effects required a reduction of the dosage or withdrawal of the drug. Our results and those reported elsewhere indicate that non-responders to treatment with oxybutinin alone or in combination with imipramine are unlikely to improve with currently available drug therapy.