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Overactive Bladder

By Staff


6/20/2012


US Pharm. 2012;37(6):17-18.

Urinary Urgency and Frequency

Overactive bladder (OAB) is a condition characterized by two urinary symptoms: urgency and frequency. Urgency means the sudden need to urinate; frequency is defined as having to urinate more than eight times in 24 hours. OAB also may be accompanied by urge incontinence (urine leakage). These symptoms can cause a number of problems for patients, including interrupted sleep, skin or urinary tract infections, an increased risk of falls, and depression.

The normal bladder stretches until it fills with enough urine to signal the nervous system that it is time to empty through urination. The muscle in the bladder wall contracts, pushing the urine out of the bladder. At the same time, the urinary sphincter muscle relaxes, allowing the urine to flow out of the bladder. If the bladder-wall muscle contracts too often, symptoms of OAB can result.

In many cases, the cause of OAB cannot be determined. Some known causes of the condition are bladder inflammation or infection, bladder stones, and bladder cancer. In men, an enlarged prostate can cause OAB.

There are several tests that can help identify the cause of OAB symptoms. If a cause is determined, treatment centers on eliminating it. If no cause is found, treatment focuses on medications that relax the bladder-wall muscle to decrease the abnormal contractions. Medications used to relieve symptoms include those with anticholinergic and antispasmodic activity. Various exercises may be used to retrain the bladder muscles and the urinary sphincter so that they work together to relieve the symptoms. In OAB patients with severe incontinence who cannot hold large amounts of urine, surgery to enlarge the bladder has been successful.

Symptoms Can Affect Many Aspects of Daily Life

Overactive bladder (OAB), with or without incontinence, afflicts millions of people worldwide. The sudden urge to urinate, frequent urination, and urine leakage are symptoms that negatively affect a person’s quality of life. More common in women and with increasing age, OAB may be due to a variety of conditions, including bladder infection, bladder stones, obstructed urine flow, bladder cancer, and neurologic disorders such as stroke, spinal cord injury, and multiple sclerosis. In men, an enlarged prostate may affect bladder emptying. Often, OAB has no identifiable cause.

Symptoms and Diagnosis

The occurrence of urgency and frequency alone is sometimes called “dry” OAB, whereas these symptoms accompanied by urine leakage are known as “wet” OAB. Many aspects of a person’s everyday life can be affected, including social functioning, work, travel, and sleep. Symptoms of OAB can lead to urinary tract infections, skin irritation, inadequate sleep, and depression. In older people, OAB has been linked to an increase in falls and fractures. Frequent nighttime urination (two or more times during the night) can cause chronic exhaustion that results in problems functioning during the day.

OAB is diagnosed by reviewing symptoms and performing a physical examination. Specific tests for determining bladder function include urinalysis, x-rays, ultrasound, and measurement of the amount of urine left in the bladder after urination. Other tests can determine how easily urine leaks from the bladder when the patient coughs or exercises. Cystoscopy provides a view of the inside of the bladder. Several of these tests may be performed in order to pinpoint the bladder problem and design a treatment plan.

Available Treatments

OAB treatment depends upon the specific symptoms the patient is experiencing and the degree to which these symptoms affect activities of daily living. If an underlying cause (such as infection) is discovered, it will be treated first to determine whether bladder symptoms improve. Most often, OAB does not have a discoverable cause.

Patients with OAB should drink water as instructed by their doctor. Some patients find it beneficial to limit caffeine and to avoid spicy or acidic foods, if they cause bladder irritation. Bubble baths and irritating soaps should not be used.

Anticholinergic drugs (also known as muscarinic antagonists) are used to relax the bladder muscle and relieve abnormal contractions. These agents are available as long-acting oral medications or as patches applied to the skin and changed every 3 or 4 days. Common side effects include dry mouth, blurred vision, and constipation. Flavoxate, an antispasmodic drug approved to treat OAB, works by relaxing spasms in the urinary tract. Certsain tricyclic antidepressants have been useful for OAB because their effects are similar to those of anticholinergic drugs. Tricyclic antidepressants cause dry mouth, blurred vision, and dizziness, so they are best taken at bedtime.

One method of retraining the bladder to improve its function involves scheduling specific times to urinate while holding in the urine the rest of the time. Pelvic-floor exercises such as Kegels also help train the urinary sphincter muscle, which allows urine to flow normally. Greater control of the sphincter will help inhibit urine leakage. In severe cases of OAB not relieved by medication, bladder retraining, or pelvic-floor exercises, surgery to increase bladder capacity may be required.

To comment on this article, contact rdavidson@uspharmacist.com.

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