Urge or urinary incontinence -- an embarrassing and often debilitating set of maladies afflicting some 17 million Americans -- can be relieved by newer drugs that are less likely to cause a troubling side effect, says a Stanford University Medical Center urologist who helped compare two drugs used in treating the condition.

A multicenter study shows that a controlled-release version of a commonly used incontinence drug worked most effectively because it reduced the peaks and valleys of treatment throughout the day and night, said Rodney U. Anderson, M.D., professor of urology at Stanford. He is an author of the study published in the April issue of the Mayo Clinical Proceedings journal. The timed-release drug offered the added benefit of working without increasing the incidence of dry mouth, a common side effect that often discourages patients from staying with their medications, Anderson said.

Many patients are too embarrassed to seek help for urinary incontinence, which is characterized by the need to void one's bladder many times during the day. This sudden urge results in accidents if a restroom can't be found immediately and lost sleep because of frequent nighttime trips to the bathroom.

With sufferers missing business appointments, social engagements and other useful activities because of the embarrassment of urge incontinence, the potential economic and social loss is staggering, Anderson said. In 1995, the National Institute on Aging estimated the cost of urinary incontinence among senior citizens at $26.3 billion annually. The condition is a common reason that elderly men and women are moved into nursing homes, Anderson said.

While a number of surgical and minimally invasive treatments, including implantation of a pacemaker-type device, are available from specialists for persistent cases, the primary method of treatment during the past 30 years has been a drug known as oxybutynin chloride. Anderson said the medication works effectively for mild to moderate cases but causes dry mouth in more than 50 percent of users. Then in 1998, a drug known as tolterodine tartrate was introduced and was found to be effective in treating incontinence symptoms while causing dry mouth in about 40 percent of users.

The study indicates that a timed-release version of oxybutynin may be the most effective drug of all, while reducing dry mouth for two-thirds of users. A timed-release version of tolterodine tartrate offers similar promise but wasn't available in time to be included in the study, said Anderson.

Both oxybutynin and tolterodine work by relaxing the muscle spasms that cause voiding and the nerves that send the signals.

The six-month study at 37 medical centers involved 276 women and 56 men. Patients were treated for 12 weeks with a total daily dose of either 10 mg of extended-release oxybutynin or 4 mg of tolterodine.

The study, which compared the two drugs, found that extended-release oxybutynin chloride reduced the number of reported urge-incontinence episodes from 25.6 per week to 6.1 per week. Tolterodine cut the number of episodes from 24.0 per week at baseline to 7.8 per week at the end of the study.

"The bottom line is that this 'head-to-head' study shows us that we have good medications offering minimal side effects that will allow people to expand their range of activities without embarrassment," he said.

"This study was particularly significant in the current health care environment where primary-care physicians, rather than specialists, are writing the majority of prescriptions for 'overactive bladder.' It is really important that they receive appropriate information to help them write the best prescription for each patient," Anderson said.