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Urinary incontinence (UI), a disorder that involves an involuntary loss of urine, has both medical and psychological consequences.1,2 Worldwide, it is estimated that >200 million people suffer from UI, with more than 12 million people affected in the United States.3,4 Women are twice as likely as men to experience the condition, and the prevalence of UI increases with age.4 In the United States, the annual expenditure on direct costs alone was estimated at $16 billion in 1995.5 UI is socially limiting and potentially embarrassing for patients, so it is underreported to health care providers.6
Types of UI
UI is classified as either acute or chronic. Acute UI can be caused by acute medical problems such as infections (cystitis), delirium, diabetes, or congestive heart failure.7 It also can be caused by prescription medications such as diuretics or neuroleptics.7 Nonprescription drugs, herbal supplements, and dietary components (eg, caffeine, artificial sweeteners) can increase diuresis and exacerbate UI. Once the cause of the acute UI has been treated or removed, normal continence generally is restored.
There are several types of chronic UI: stress, urge, mixed, overflow, or functional incontinence.
•Stress incontinence is the loss of urine following an increase in abdominal pressure or stress, such as increased physical activity, coughing, or sneezing; this type is characterized by the loss of small amounts of urine, with little or no nocturia8
•Urge incontinence occurs when the urge to urinate precedes the involuntary loss of urine by a relatively short time (a few seconds to minutes); the sudden urge to urinate does not allow the patient to reach the bathroom in time, and large amounts of urine may be lost9
•Mixed incontinence is a combination of stress and urge incontinence
•Overflow incontinence occurs when the bladder becomes distended to the point where it can no longer resist urine outflow; patients may complain of urinary hesitancy and experience the loss of small amounts of urine constantly throughout the day7
•Functional incontinence occurs in patients who are unable to reach the commode to void; they may be physically restrained, sedated by medications, or cognitively impaired so that they are unaware that they need to urinate7
Nonpharmacologic Management of UI
A full medical history and physical examination should be conducted before starting treatment so as to fully elucidate the type of UI. Nonpharmacologic therapies should be attempted as first-line treatment options in all patients, because these therapies have been shown to be as effective or more effective than pharmacologic options.8 Kegel exercises and bladder training allow patients to manage their incontinence and to reduce the number of voiding accidents.8 It is also very useful to explain the common symptoms of UI and how to manage them with behavior modifications (frequent toileting) and personal care hygiene products.
Pharmacologic Management of UI
Normal micturition occurs when the muscular layer surrounding the bladder, the detrusor muscle, contracts in coordination with relaxation of the sphincters of the bladder neck. Detrusor muscle contraction is primarily mediated by cholinergic stimulation of muscarinic receptors on the bladder smooth muscle. Anticholinergic agents antagonize muscarinic receptors, resulting in a relaxation of the bladder smooth muscle, and are therefore useful for urge incontinence.1
Oxybutynin chloride is a commonly used anticholinergic agent that targets the M2 and M3 receptors. It is available in immediate-release (Ditropan), extended- release (Ditropan XL), and transdermal (Oxytrol) formulations. The side effects are dose-related and include dry mouth, constipation, and blurred vision. Patients may favor the XL formulation because it is associated with less dry mouth.
The transdermal formulation of oxybutynin is applied twice weekly (every 3-4 days) to dry, intact skin on the abdomen, hip, or buttock. It is important to rotate sites and to avoid using the same application site within 7 days. The patch is more expensive but also is associated with less dry mouth than the immediate-release formulation.10 Common adverse reactions with the patch include pruritis and application site erythema, as well as dry mouth.
Tolterodine tartrate (Detrol) is another anticholinergic agent used to treat UI. It has a greater affinity for M2 receptors in the bladder versus the salivary glands, resulting in lower rates of dry mouth. Tolterodine has both immediate-and extendedrelease formulations, with the latter preferred because of lower rates of anticholinergic side effects. When comparing oxybutynin with tolterodine, oxybutynin has been shown to be more effective but to produce more side effects.11
Tricyclic antidepressants such as amitriptyline or nortriptyline also may be used to treat UI due to their anticholinergic side effects. They are, however, not first-line agents because they produce central nervous system (CNS) and cardiovascular side effects.
A number of new agents are available for UI. Trospium chloride (Sanctura) is a muscarinic receptor antagonist that is dosed once daily on an empty stomach. Trospium does not have CNS side effects due to its quaternary amine structure, which does not permit it to cross the bloodbrain barrier.12 This attribute makes it favorable for elderly patients who are at risk for cognitive impairment secondary to anticholinergic medications.
Solifenacin succinate (VESIcare) is another newly approved drug for UI. It is a nonselective muscarinic antagonist that is selective for the bladder.9,12 Solifenacin is dosed once daily and may be given with or without food.12
Darifenacin (Enablex) is a selective M3 receptor antagonist that came on the market in 2004. Although it has a higher affinity for the bladder than for the salivary glands, the clinical implications of the dry-mouth effect are not yet fully understood.9,12 Darifenacin is dosed once daily and should not be crushed or chewed.12
When patients start medication therapy, it is essential to explain how each medication is administered and to inform them of the common side effects they may experience such as dry mouth, constipation, or drowsiness. Information regarding crushing of medications and cost is also valuable to patients because it may influence which product would suit them better. Caregivers for elderly patients also should be reminded to watch for signs of altered mental status when starting anticholinergic agents.
In addition, it is important to encourage nonpharmacologic options such as Kegel exercises and bladder training along with adherence to medication therapy. Finally, follow-up with patients is necessary to monitor their response to drug therapy. If medical therapy is not providing any benefit or if side effects are dose-limiting, the patient should be referred to a urology specialist for a more extensive workup.
Dr. Hajjar is an assistant professor of clinical pharmacy at the University of the Sciences in Philadelphia, Philadelphia College of Pharmacy.
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