Intravesical electromotive administration of oxybutynin in patients with detrusor hyperreflexia unresponsive to standard anticholinergic regimens

Purpose: About 15% to 20% of patients with detrusor hyperreflexia do not be nefit from oral oxybutynin regimens, frequently because of unpleasant side effects. Several reports indicate that intravesical oxybutynin is effective in many of these patients but there are some who still fail to respond. Materials and Methods: A select group of 10 adults with detrusor hyperrefle xia unresponsive to standard oral and intravesical oxybutynin regimens were treated at weekly intervals with 5 mg. oxybutynin orally, or 5 mg. oxybuty nin in 100 ml. intravesically for 60 minutes of passive diffusion and for 3 0 minutes with 5 mA.. electrical current. Each treatment (plus oral placebo and 2 intravesical controls) was associated with an 8-hour, full urodynami c monitoring session, and periodic blood and bladder content sampling. Results: There was no significant objective improvement with oral or intrav esical passive diffusion oxybutynin. Conversely there was significant impro vement in 5 of 6 objective urodynamic measurements with intravesical electr omotive oxybutynin. Plasma profiles were a single peak and decay following oral oxybutynin and 2 distinct peaks with intravesical passive diffusion an d electromotive oxybutynin. Area under the curve for intravesical passive d iffusion were 709 ng. per 8 hours versus oral 1,485 (p <0.05) versus intrav esical electromotive 2,781 (p <0.001). Bladder content samples confirmed ox ybutynin absorption. Oral oxybutynin caused anticholinergic side effects in 7 of 10 patients. There were no side effects with intravesical passive dif fusion or electromotive administrations. Conclusions: Accelerated intravesical administration results in greater bio availability and increased objective benefits without side effects in previ ously unresponsive patients compared with oral and intravesical passive dif fusion oxybutynin administration.