- CONDITION CENTERS
Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.
In the United States, over 6 million individuals seek medical treatment annually for urinary tract infections (UTIs), and one fifth of those individuals are treated in the emergency department.1 UTIs are considered to be one of the most common medical complaints among women aged 18 years and older.2,3 Because women have a shorter urethra than men, they are more susceptible to UTIs, due to the retrograde migration of bacteria from the skin.3 UTIs affect 20% of women at some point during their lifetime, and acute bacterial cystitis infections, also known as acute lower UTIs, are responsible for 3.6 million annual physician visits by women between the ages of 18 and 75.1,4
The majority of women have recurrent infections, and at least 25% of women will have another infection within 1 year.4 The microorganism Escherichia coli causes 75% to 90% of uncomplicated UTIs,3,5 whereas Staphylococcus saprophyticus causes an estimated 5% to 15% of UTIs, frequently in younger women. Enterococci and aerobic gram-negative rods other than E coli, such as Klebsiella species and Proteus mirabilis, are isolated in the remainder of UTIs.4,5
Various conditions may make individuals more susceptible to UTIs, including pregnancy, diabetes, urinary stones, the presence of urinary catheters, a history of recurring UTIs, and urinary obstructions such as those caused by an enlarged prostate.3
The most prevalent signs and symptoms associated with UTIs include3-6:
Various nonprescription products are currently available for providing relief from the pain associated with UTIs (Table); OTC tests to detect or confirm the presence of a UTI also are available. Nonprescription products marketed as urinary analgesics contain the analgesic phenazopyridine hydrochloride, which is an azo dye that exerts a local anesthetic or analgesic effect on the mucosa of the urinary tract. The precise mechanism of action of phenazopyridine is unknown.7 It is indicated for the symptomatic relief of urinary burning, itching, frequency, and urgency often associated with UTIs.7 It is important for patients to be advised that phenazopyridine does not treat a UTI but only acts as an analgesic and they should consult their primary health care provider for further evaluation and treatment. Common adverse effects of phenazopyridine include headache, dizziness, and abdominal cramps. Patients should be advised to take 2 tablets after meals 3 times a day as needed with a full glass of water for no more than 2 days without consulting a physician.7,8 Patients should be reminded to take no more than 12 tablets in a 48-hour period.7,8 These analgesics can be used in conjunction with the antibiotics prescribed for the UTI. Patients should be advised to consult their physician if they experience pain or discomfort lasting longer than 2 days.7 Phenazopyridine may cause discoloration of urine to orange or red color and also may cause staining of clothing.7
Only one nonprescription product on the market contains the antibacterial agent methenamine and the analgesic sodium salicylate.9 The recommended directions for use of the product are 2 tablets with a full glass of water 4 times a day. This product is not to be used as a replacement for antibiotic therapy.9 Patients with aspirin allergies, those with a history of gastric ulcers or bleeding disorders, those on anticoagulation therapy, or those with diabetes, gout, or arthritis should always consult their physician prior to using this product.9
In addition to analgesic products, nutritional supplements are available that contain cranberry for preventive therapy. These products are marketed to assist in maintaining a healthy urinary tract by preventing bacteria from attaching to the bladder wall.10 The exact mechanism of action is unknown, but some research suggests that cranberry may inhibit bacteria, particularly E coli, from adhering to the bladder, kidneys, and urethra.11
Various tests are available that detect nitrites, and some detect both leukocytes and nitrites. They are used for early detection in individuals with a history of recurring UTIs and to confirm that a UTI has been cured after a complete course of antibiotic therapy.3 A dose of 250 mg vitamin C may result in a false-negative result, because ascorbic acid inhibits the nitrite test reaction.3 Patients should be advised to wait at least 10 hours after ingesting vitamin C before testing.3 Patients also should be informed that if >500 mg vitamin C are ingested within 24 hours of testing, they may obtain a false-negative result for tests that detect leukocytes.3 Patients on strict vegetarian diets also may obtain inaccurate results, because the diet provides insufficient urinary nitrites, which can cause false-negative nitrite results with UTI tests.3 Tetracycline also may produce a false-negative reading for nitrites.3 Women should be reminded not to use tests strips during their menstrual cycle, because blood may cause a false-positive result.3
Pharmacists should ensure that patients clearly understand that urinary tract analgesics are not intended to treat UTIs and that they should always consult their primary health care provider for further medical care. Patients who have never had a UTI or those experiencing severe symptoms also should be referred for further medical evaluation. Those patients susceptible to UTIs may benefit from various nonpharmacologic measures that may prevent or reduce the incidence of UTIs; for example, drinking plenty of water daily, voiding when needed, not resisting the urge to urinate, always wiping from front to back after urination, and taking showers instead of baths.12
Patients electing to use urinary tract analgesics should be counseled on the recommended dosage and duration of use, as well as the possible adverse effects that may occur. Patients using test kits to detect UTIs should be reminded to immediately consult their primary care provider if they obtain a positive test result or if they obtain a negative test result but still experience any urinary discomfort or any of the symptoms commonly associated with UTIs. For more information, please visit health.nih.gov/topic/UrinaryTractInfections.