Treatment of detrusor instability with oxybutynin rectal suppositories

Our aim was to determine whether oxybutynin hydrochloride suppositories can be used as a treatment for detrusor instability in patients who have not been able to tolerate oral pharmacological agents. A retrospective chart review of 25 women diagnosed with detrusor instability and treated with oxybutynin rectal suppositories was conducted. Each suppository contained 5 mg oxybutynin, 15 mg micronized Sila gel, and 1.25 g of a fatty acid base. Patients were started on one suppository twice daily and then dose titrated as tolerated. The range of the total daily dose was 5-20 mg. Nine of 25 women (36%) had greater than a 50% overall subjective improvement and 3 (12%) had some improvement. Seven of the 12 responders (58%) continued to use the suppositories for a prolonged period of time (> 90 days). The most common side effects reported were dry mouth 48% and constipation 14.3%. One patient with polymyositis developed a serious anticholinergic reaction which required hospitalization. It was concluded that patients who are unable to tolerate oral anticholinergic and antispasmodic agents for the treatment of detrusor instability may benefit from oxybutynin rectal suppositories.