NEW YORK (Reuters Health) – While oxybutynin is often used prophylactically to reduce irritative urinary symptoms related to intravesical bacillus Calmette-Guerin (BCG) therapy for bladder cancer, it actually seems to make symptoms worse, according to the results of a randomized controlled trial.
“These unanticipated results may be a result of anticholinergic medications causing an element of incomplete bladder emptying and allowing an increased BCG dwell time,” the study’s authors suggest in their paper in the Journal of Urology online November 2.
Dr. Adam S. Kibel, at Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues point out that intolerable side effects of intravesical BCG treatment lead one in five patients to stop treatment. Oxybutynin extended release is approved for treating overactive bladder and is often prescribed for BCG-induced lower urinary tract symptoms – but its efficacy in this setting “is entirely anecdotal.”
The team therefore conducted a double-blind trial in which 50 patients with noninvasive bladder cancer were randomly assigned to receive extended-release oxybutynin 10 mg daily or placebo on the night before starting 6 weekly BCG treatments and continuing throughout the 6 weeks.
The investigators found that the oxybutynin group had significantly greater increases in urinary frequency scores (p=0.004) and in burning sensation on urination (p=0.04). Furthermore, other symptoms such fever, dry mouth and constipation were also more common in the treatment group than the control group.
Overall, the findings may explain why fewer patients in the oxybutynin arm completed BCG treatment, the authors suggest.
“This trial provides level-one evidence against the prophylactic use of anticholinergic therapy during BCG intravesical treatment,” Dr. Kibel and colleagues conclude.
“The other options for management of BCG-induced symptoms,” they continue, “include BCG dose reduction, antibiotics, steroid therapy, or treatment cessation, but these approaches have limited evidence and are also based largely on anecdotal experience.”
