Detrol

Harvey MA, Baker K, Wells GA. Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis. Am J Obstet Gynecol 2001; 185:56-61

* BACKGROUND Urge urinary incontinence has drawn attention recently, with a number of studies looking at which treatment provides the best results with the fewest side effects. The authors of this study performed a meta-analysis comparing treatment outcomes and side effects for short-acting oxybutynin and tolterodine.

* POPULATION STUDIED The trials included in this meta-analysis studied patients older than 18 years and who were complaining of urge incontinence or an association of frequency (> 8 times per day) and urgency, or had received a diagnosis of detrusor instability. Patients were excluded who had used co-interventions within the 14 days preceding the trial. No further information was available on the populations studied, making it difficult to determine if the patients were similar to those of a primary care practice.

* STUDY DESIGN AND VALIDITY The authors conducted a rigorous literature search without language constraint for published and unpublished studies that were randomized or quasirandomized and double blinded comparing tolterodine with oxybutynin. At least one arm of each study needed to be randomized to 1 to 2 mg tolterodine twice daily and the other arm to 2.5 to 5 mg of oxybutynin 3 times daily. Two independent reviewers decided which trials would be considered in the analysis according to priori eligibility criteria.

Four trials were included in the final analysis. Quality scores for the included studies ranged from 3 to 5 on the Jadad scale (5 being the highest-quality study). All studies were graded B (unclear) regarding the adequacy of allocation concealment, because none reported this information. Pharmaceutical companies sponsored all 4 studies.

One limitation of this meta-analysis is that it did not include long-acting oxybutynin (Ditropan XL) or tolterodine (Detrol LA), which may be better tolerated. Long-acting oxybutynin was compared with short-acting tolterodine in a recent study and was found modestly more effective, with an equal side effect profile and similar cost. (1)

* OUTCOMES MEASURED The primary outcomes included the number of incontinent episodes per 24-hour period, the quantity of pads used per 24 hours, the number of micturitions per 24 hours, and the mean voided volume per micturition. Secondary outcomes included the number of patients with side effects and withdrawals attributed to side effects, the number of patients changing dose, urologic measurements, and quality of life.

* RESULTS Oxybutynin produced a statistically and clinically significant decrease in the number of incontinent episodes per 24-hour period (weighted mean difference = 0.41; 95% confidence interval [CI], 0.04-0.77). Both drags decreased the number of episodes, but the oxybutynin-treated group averaged 0.5 fewer episodes per day. Patients taking tolterodine reported significantly less dry mouth (relative risk [RR] = 0.54; 95% CI, 0.48-0.61) and less moderate to severe dry mouth (RR=0.33; 95% CI, 0.24-0.45). The risk of withdrawing from the study because of side effects was decreased by 37$ in the tolterodine group (RR=0.63; 95% CI, 0.4643.88).

RECOMMENDATIONS FOR CLINICAL PRACTICE

Oxybutynin is superior to tolterodine in efficacy, causing nearly one half fewer episodes of urinary incontinence per day. Tolterodine is better tolerated with less moderate-to-severe dry mouth and fewer dropouts because of medication side effects. For now, oxybutynin should be the first-line choice, since it is available generically and is considerably less expensive (approximately $20 per month for oxybutynin vs $75 per month for tolterodine). Tolterodine or extended-release oxybutynin should be used for those who cannot tolerate this medication because of side effects.

REFERENCE

(1.) Appell RA, Sand P, Dmochowski R, et al, Prospective randomized controlled trial of extended-release oxybutynin chloride and tolterodine tartrate in the treatment of overactive bladder: results of the OBJECT study. Mayo Clin Proc 2001; 76:358-63.

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