Prospective Randomized Controlled Trial of Extended-Release Oxybutynin Chloride and Tolterodine Tartate in the Treatment of Overactive Bladder: Results of the OBJECT Study
Appell RA, Sand P, Dmochowski R, et al.
[Mayo Clin Proc. 2001;76:358–363]
One of the primary limitations of anticholinergic agents for the treatment of overactive bladder is problematic side effects, primarily dry mouth. In many cases, the therapeutic advantage is overshadowed by the adverse effects of anticholinergic therapy. Two new medications for the treatment of overactive bladder are being marketed on the basis of improved tolerability. Appell and colleagues1 recently reported the results of a prospective randomized double-blind, placebo-controlled trial comparing the tolerability and effectiveness of extended-release oxybutynin chloride (Detrol XL™) versus tolterodine tartate (Detrol™) in the treatment of overactive bladder.
A total of 378 men and women were randomized to receive extended-release oxybutynin 10 mg/day versus tolteradine tartate 2 mg b.i.d. The incidences of dry mouth or any other adverse event were not significantly different between the two drug regimens. The discontinuation rates for adverse events were also not significantly different between the two different agents. Both drugs significantly improved the incidence of urge incontinence per week, the total number of incontinent events over the 12-week study interval, and the micturition frequency. Extended-release oxybutynin chloride was significantly more effective than tolterodine tartate in improving the incidence of urge incontinence and decreasing micturition frequency.
Both of the new agents evaluated for overactive bladder appear to reduce adverse events relative to historical agents, such as propantheline and immediate-release oxybutynin. The first direct comparison study of these new agents demonstrates a modest, but clinically significant advantage of extended-release oxybutynin.
One criticism of the study is that the long-acting formulation of tolterodine tartate was not utilized. At the time the study was designed, this new formulation of tolterodine tartate was not available. A recent comparative study showed statistically but not clinically significant advantages of the extended-release formulation of tolterodine tartate over the immediate-release formulation.2
Both of the agents have side effects and, in many cases, incontinence and micturition frequency are improved but not eliminated. Thus significant opportunities remain to create a pharmacologic agent that will more effectively relieve overactive bladder with fewer adverse events.
References
- 1.Appell RA, Sand P, Dmochowski R, et al. Prospective randomized controlled trial of extended-release oxybutynin chloride and tolterodine tartate in the treatment of overactive bladder: results of the OBJECT Study. Mayo Clin Proc. 2001;76:358–363. [PubMed] [Google Scholar]
- 2.Van Kerrebroeck P, Kreder K, Jonas U, et al. Tolterodine once-daily: superior efficacy and tolerability in the treatment of the overactive bladder. Urology. 2001;57:414–421. doi: 10.1016/s0090-4295(00)01113-4. [DOI] [PubMed] [Google Scholar]