Medications and Stress Incontinence

By Barbara C. Bourassa

For people who suffer from stress incontinence (SUI), two of the most common treatments include pelvic floor–muscle exercises and surgery. Unlike with urge incontinence or overactive bladder (OAB), for which medication is an option, there are currently no Food and Drug Administration (FDA)–approved drugs for the treatment of SUI.

Here's a little-known fact, however: Some doctors will treat mild cases of SUI by using medications off-label. Simply put, using a drug off-label means taking it to treat a condition that hasn't been approved by the FDA. This phenomenon raises a number of important questions for anyone suffering from SUI. Why are there no medications for SUI? Which drugs are being used off-label to treat it? How effective are these drugs, and what are the pros and cons of this approach?

The reason that treatments for SUI do not include drugs is the same reason doctors don't use medication to treat a sprained ankle, says Dr. Steven Swift, professor of obstetrics and gynecology at the Medical University of South Carolina in Charleston, South Carolina. "We don't have a medication that can fix a damaged ligament," he says. "The usual treatments are rest, rehabilitation, and surgery. Stress incontinence is a muscular skeletal condition, and there are no medications to treat weak muscles."

Those weak muscles include two types of tissue which control the urethral sphincter: somatic muscles, also known as voluntary muscles or the type of muscles you can control; and smooth muscles, also known as involuntary muscles.

One class of drugs that has been used to treat SUI off-label is called alpha-adrenergic agonists. These drugs, which include nasal decongestants, work by tightening the smooth muscles in the urethral neck, which can, in turn, reduce incontinence.

"Sudafed is often used [to treat SUI], but there's no clinical data to support its efficacy," says Dr. Craig Comiter, chief of urology, director of female urology and urodynamics, and associate professor of surgery at the University of Arizona Health Sciences Center in Tucson, Arizona. "The mechanism of the action makes sense—it contracts the muscles of the [urethral] sphincter."

That's the good news. The bad news is that the drug also tightens blood vessels, which increases the risk of high blood pressure and stroke. "You don't want to take a risky medication for a quality-of-life issue," says Dr. G. Willy Davila, chairman of the department of gynecology at the Cleveland Clinic Florida in Weston.

Surprisingly, there's an alpha adrenergic agonist, a veterinary drug called Proin, for the treatment of incontinence in dogs, says Davila, but no such medication for humans. (The side effects, such as high blood pressure, have not been shown to occur in pets, according to www.vetinfo4dogs.com ).

A second class of drugs, called anticholinergics, is used to treat urge incontinence or OAB. If a person has mixed incontinence, meaning they suffer from both urge and stress incontinence, these medications can bring some relief, but they're actually only treating the symptoms caused by urge incontinence, Swift notes.

Local forms of estrogen, such as a cream or tablet that is used in the vagina, can help with certain cases of SUI, says Davila. "Estrogen works fairly well for menopausal women who are atrophic, as it increases the blood flow to the urethra, and the blood flow to the urethra is responsible for one-third of the urethral pressure," he explains. This form of estrogen should not be confused with oral estrogen, which can precipitate incontinence because it relaxes the urethra sphincter, he says. Also, the local estrogen is most often used as a co-therapy, meaning it is applied two or three nights a week in addition to other treatments, such as Kegel exercises.

Some doctors also prescribe an older type of antidepressants, known as tricyclics, for SUI. Tricyclics, such as imipranine, work in two ways: They act like alpha adrenergic agonists, tightening the smooth muscle of the urethral sphincter, and they function like anticholinergic drugs, relaxing the bladder muscles, says Swift. Results are mixed; Davila says they can be effective in very low doses, especially when combined with estrogen, but Swift says he finds "the drugs are weak at both actions."

The last type of drug that's sometimes used for treating SUI has received the most attention. Duloxetine, a serotonin and norepinrphrine reuptake inhibitor (SNRI) antidepressant, is approved for treating pain and depression in the United States. The mechanism of how this drug helps reduce SUI in cats is well documented, according to both doctors. In theory, constantly stimulating a muscle over time will cause it to strengthen, and duloxetine works by increasing nerve stimulation to the urethral sphincter muscle. The drug was approved for the treatment of SUI in Europe in 2004, and many people thought it would receive FDA approval for SUI use in 2005, but the drug's safety remained questionable. The FDA approval process was halted when Eli Lilly, the drug's manufacturer, pulled the application.

Duloxetine, like the other medications, can be used off-label. However, the experts note, with any unlabeled use, it's extremely important to talk to your doctor or medical practitioner regarding the risks. Always consult a physician or medical practitioner before taking any drug for any other use than its intended purpose.