Botox injections work as well as the oral medications commonly used to treat women with urgency urinary incontinence. That’s according to a study published Thursday in the New England Journal of Medicine.

The research involved 241 women who had suffered from urgency urinary incontinence, a condition affecting nearly a fifth of older women in the U.S., according to the study. As its name implies, this form of incontinence involves “unpredictable” leakage of urine that occurs when the bladder muscles contract at the wrong time, causing a strong urge to urinate.  At the start of the study, participants reported an average of five episodes of urgency incontinence per day.

Researchers gave half the women Botox (botulinum toxin) plus an oral placebo; the other half received placebo injections and the oral drug solifenacin, which is in a class of drugs called anticholinergics. (Some later switched to trospium, another drug in that class.) Anticholinergics rein in bladder muscle contractions via the nervous system. They have long been the most common treatment for urgency incontinence, but side effects such as dry mouth and constipation make them problematic for many patients.

The women kept incontinence diaries and at monthly check-ins reported on how well their incontinence was being managed, rated their quality of life and noted any side effects they experienced.

Both treatments cut the average number of daily episodes of incontinence by about the same amount – 3.4 fewer episodes for the oral treatment and 3.3 for Botox. Only 13 percent of those taking the oral drug experienced complete resolution of their urgency incontinence, compared to 27 percent of those on Botox. Dry mouth affected 46 percent of the oral-drug group and 31 percent of the Botox group, while 28 percent of those using Botox experienced urinary tract infections versus 15 percent of those on the oral drug. Five percent of women in the Botox group experienced incomplete emptying of the bladder and required short-term catheterization; that didn’t happen to any women in the other group. Overall, both groups reported similar improvements in quality of life.

The study concludes that these findings should help physicians and patients make better-informed decisions about options for treating this common form of urinary incontinence.