CHICAGO -- Once-daily tolterodine 4 mg is an effective, well tolerated, and convenient therapy for overactive bladder in women, two investigators said in separate presentations at the annual meeting of the American Urogynecologic Society.
The efficacy and safety of twice-daily tolterodine 2 mg (Detrol) in the treatment of overactive bladder (OAB) is well established. Recently, a 4-mg extended-release (ER) formulation has become available.
The first study showed that efficacy, safety, and tolerability of the ER formulation are maintained over at least 1 year of treatment, while the second study suggested that tolterodine ER 4 mg is more effective and better tolerated than the old immediate-release (IR) 2-mg formulation. Both studies were funded by the Pharmacia Corp., manufacturer of Detrol.
In the first study, Dr. Alan Garely of North Shore-Long Island Jewish Health System, Great Neck, N.Y., reported on 886 women with OAB who chose to continue treatment with tolterodine ER 4 mg after completing a 12-week, double-blind, randomized trial in which that formulation was compared with tolterodine IR 2 mg.
A total of 634 patients completed 12 months of open-label treatment with tolterodine ER 4 mg.
Primary reasons for withdrawal were adverse events (10%) and lack of efficacy (10%).
Efficacy was maintained during 12 months of treatment, and there was no evidence of tolerance. At 12 months, the number of micturition episodes per day was reduced by 21%. The number of urge incontinence episodes per week was 81% lower, compared with baseline, while the volume voided per micturition was 33% greater.
These values were not significantly different from those observed at 12 weeks of treatment in the double-blind study, nor after 3 months in this open-label study, he noted.
At 1 year, 75% of the women perceived an improvement in their bladder condition, and 53% noted an improvement in the sense of urgency, about the same percentages seen at 12 weeks.
No adverse events increased over the 12-month period. Dry mouth was reported by more than 5% of the patients: 25% of patients reported dry mouth in the 12-week randomized study and 12% reported it in the 1-year trial, but most of the dry mouth was of mild intensity, Dr. Garely commented.
In the second study, conducted by Dr. Steven Swift, 1,235 women with OAB were randomized to receive tolterodine ER 4 mg once daily tolterodine IR 2 mg twice daily or placebo for 12 weeks. The ER version was 24% more effective than tolterodine IR 2 mg in reducing incontinence episodes.
The median reduction in incontinence episodes was reduced by 71% with the 4-mg ER formulation vs. 57% with 2-mg IR and 33% with placebo.
Compared with placebo, tolterodine ER 4 mg also produced greater reductions in pad use (37.5% vs. 12%) and micturition frequency (18% vs. 11%). At the same time, increases in voided volume per micturition were greater than with placebo (27% vs. 10%).
These improvements were similar to those seen with tolterodine IR, said Dr. Swift of the Medical University of South Carolina, Charleston, S.C.
Dry mouth was lower with the ER than the IR formulation (25% vs. 31%). The frequency of other adverse events was low and similar between the groups. Withdrawal rates were also similar between the groups, and there were no safety concerns, he said.
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