Intravesical application of oxybutynine: mode of action in controlling detrusor hyperreflexia. Preliminary results

Topical oxybutynine (Oxy) has been used successfully in neurogenic bladder patients who remained wet on oral anticholinergics or could not tolerate oral medication. However, little is known about the pharmacokinetics of intravesical Oxy. The aim of this study was to evaluate the resorption rate of intravesically given Oxy in the bladder in comparison with oral intake, and to find out which pharmacological properties of the drug are responsible for its effect when given intravesically. Our results indicate that peak plasma levels of intravesical Oxy appear later, are lower and stay longer compared to oral intake. Cystometries before, 20 min and 2 h after intravesical application of Oxy indicate that the main effect of intravesical Oxy on the detrusor is systemic due to its resorption. Our findings confirm the clinical experience that intravesical Oxy is well tolerated, very efficacious and better than oral medication.