Urinary Tract Infections

Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.

In the United States, over 6 million individualsseek medical treatment annuallyfor urinary tract infections (UTIs), andone fifth of those individuals are treatedin the emergency department.¹ UTIs areconsidered to be one of the most commonmedical complaints among womenaged 18 years and older.^2,3 Becausewomen have a shorter urethra thanmen, they are more susceptible to UTIs,due to the retrograde migration of bacteriafrom the skin.³ UTIs affect 20% ofwomen at some point during their lifetime,and acute bacterial cystitis infections,also known as acute lower UTIs,are responsible for 3.6 million annualphysician visits by women between theages of 18 and 75.^1,4

The majority of women have recurrentinfections, and at least 25% of womenwill have another infection within 1year.⁴ The microorganism Escherichiacoli causes 75% to 90% of uncomplicatedUTIs,^3,5 whereas Staphylococcussaprophyticus causes an estimated 5%to 15% of UTIs, frequently in youngerwomen. Enterococci and aerobic gram-negativerods other than E coli, such asKlebsiella species and Proteus mirabilis,are isolated in the remainder ofUTIs.^4,5

Various conditions may make individualsmore susceptible to UTIs, includingpregnancy, diabetes, urinary stones,the presence of urinary catheters, ahistory of recurring UTIs, and urinaryobstructions such as those caused by anenlarged prostate.³

Signs and Symptoms of UTIs

The most prevalent signs and symptomsassociated with UTIs include^3-6:

• Cloudy appearance to urine
• Presence of blood in urine
• Foul or strong odor to urine
• Frequent urination
• Urgency to urinate
• Dysuria (discomfort or burning sensationupon urination)
• Lower abdominal pain or discomfort/pressure in the lower pelvis

Nonprescription Products

Various nonprescription products arecurrently available for providing relieffrom the pain associated with UTIs(Table); OTC tests to detect or confirmthe presence of a UTI also areavailable. Nonprescription productsmarketed as urinary analgesics containthe analgesic phenazopyridinehydrochloride, which is an azo dye thatexerts a local anesthetic or analgesiceffect on the mucosa of the urinarytract. The precise mechanism of actionof phenazopyridine is unknown.⁷ It isindicated for the symptomatic relief ofurinary burning, itching, frequency, andurgency often associated with UTIs.⁷ Itis important for patients to be advisedthat phenazopyridine does not treat aUTI but only acts as an analgesic andthey should consult their primary healthcare provider for further evaluation andtreatment. Common adverse effects ofphenazopyridine include headache, dizziness,and abdominal cramps. Patientsshould be advised to take 2 tablets aftermeals 3 times a day as needed with afull glass of water for no more than 2days without consulting a physician.^7,8Patients should be reminded to takeno more than 12 tablets in a 48-hourperiod.^7,8 These analgesics can be usedin conjunction with the antibiotics prescribedfor the UTI. Patients should beadvised to consult their physician if theyexperience pain or discomfort lastinglonger than 2 days.⁷ Phenazopyridinemay cause discoloration of urine toorange or red color and also may causestaining of clothing.⁷

Only one nonprescription product onthe market contains the antibacterialagent methenamine and the analgesicsodium salicylate.⁹ The recommendeddirections for use of the product are 2tablets with a full glass of water 4 timesa day. This product is not to be used asa replacement for antibiotic therapy.⁹Patients with aspirin allergies, those witha history of gastric ulcers or bleeding disorders,those on anticoagulation therapy,or those with diabetes, gout, or arthritisshould always consult their physicianprior to using this product.⁹

In addition to analgesic products,nutritional supplements are availablethat contain cranberry for preventivetherapy. These products are marketedto assist in maintaining a healthy urinarytract by preventing bacteria from attachingto the bladder wall.¹⁰ The exactmechanism of action is unknown, butsome research suggests that cranberrymay inhibit bacteria, particularly E coli,from adhering to the bladder, kidneys,and urethra.¹¹

OTC Tests for Detecting UTIs

Various tests are available that detectnitrites, and some detect both leukocytesand nitrites. They are used for earlydetection in individuals with a history ofrecurring UTIs and to confirm that a UTIhas been cured after a complete course ofantibiotic therapy.³ A dose of 250 mg vitaminC may result in a false-negative result,because ascorbic acid inhibits the nitritetest reaction.³ Patients should be advisedto wait at least 10 hours after ingestingvitamin C before testing.³ Patients alsoshould be informed that if >500 mg vitaminC are ingested within 24 hours oftesting, they may obtain a false-negativeresult for tests that detect leukocytes.³Patients on strict vegetarian diets alsomay obtain inaccurate results, becausethe diet provides insufficient urinarynitrites, which can cause false-negativenitrite results with UTI tests.³ Tetracyclinealso may produce a false-negative readingfor nitrites.³ Women should be remindednot to use tests strips during their menstrualcycle, because blood may cause afalse-positive result.³

Conclusion

Pharmacists should ensure that patientsclearly understand that urinary tract analgesicsare not intended to treat UTIs andthat they should always consult theirprimary health care provider for furthermedical care. Patients who have neverhad a UTI or those experiencing severesymptoms also should be referred for furthermedical evaluation. Those patientssusceptible to UTIs may benefit fromvarious nonpharmacologic measures thatmay prevent or reduce the incidence ofUTIs; for example, drinking plenty ofwater daily, voiding when needed, notresisting the urge to urinate, always wipingfrom front to back after urination, andtaking showers instead of baths.¹²

Patients electing to use urinary tractanalgesics should be counseled onthe recommended dosage and durationof use, as well as the possible adverseeffects that may occur. Patientsusing test kits to detect UTIs should bereminded to immediately consult theirprimary care provider if they obtaina positive test result or if they obtaina negative test result but still experienceany urinary discomfort or anyof the symptoms commonly associatedwith UTIs. For more information,please visit health.nih.gov/topic/UrinaryTractInfections.

Table

Examples of Nonprescription Products for Urinary Tract Pain

Product

Ingredient

Manufacturer

AZO Standard Urinary Pain Relief Tablets

Phenazopyridine hydrochloride (95 mg)

Amerifit Brands

Azo Standard MaximumStrength Urinary PainRelief, Tablets

Phenazopyridine hydrochloride(97.5 mg)

Amerifit Brands

Azo Cranberry

Talc, vegetable magnesiumstearate, hydroxypropyl methylcellulose,castor oil, titaniumdioxide, carmine

Amerifit Brands

Consumers Choice SystemsUTI Relief Tablets

Phenazopyridine hydrochloride(97.2 mg)

Consumer ChoiceSystems, a division ofJason Enterprises, Inc

Consumers Choice SystemsUTI Cranberry-Plus

Natural cranberry, blueberryconcentrate powder, rice flour,cellulose powder, gelatin, silicon,magnesium stearate

Consumer ChoiceSystems, a division ofJason Enterprises, Inc

Cystex Urinary Pain ReliefTablets

Methenamine (162 mg), sodiumsalicylate (162.5 mg)

DSE Healthcare Solutions

Uricalm Pain Medicine

Phenazopyridine hydrochloride(99.5 mg)

Alva Amco PharmacalCompanies Inc

Uristat

Phenazopyridine hydrochloride(95 mg)

McNeil-PPC Inc

Table UTIs

Examples of UTI Detection Test Kits

Product

Ingredient

Manufacturer

AZO Test Strips

Amerifit Brands

Nitrites and leukocytes

Consumers ChoiceSystems UTI HomeScreening Test Sticks

Consumer Choice Systems

Nitrites and proteins

Early Detect Urinary TractInfection Test

Early Detect

Nitrites

References

• Howes D. Urinary Tract Infection, Female. eMedicine Web site. www.emedicine.com/EMERG/topic626.htm. Accessed December 6, 2008.
• About Urinary Tract Infections. Azo Web site. www.azoproducts.com/uti/about. Accessed December 7, 2008.
• Rosenthal W, Briggs G. Home Testing and Monitoring Devices. In: Berardi RR, Kroon LA, McDermott JH, et al, eds. Handbook of Nonprescription Drugs. 15th ed. Washington, DC: American Pharmacists Association; 2006:1064-1065.
• Fihn SD. Clinical practice. Acute uncomplicated urinary tract infection in women. N Engl J Med. 2003;349(3):259-66
• Urinary Tract Infections. The Merck Manual of Health and Aging [online]. www.merck.com/pubs/mmanual_ha/sec3/ch56/ch56a.html. Accessed December 9, 2008.
• Urinary tract infections - adults. Medline Plus Web site. www.nlm.nih.gov/MEDLINEPLUS/ency/article/000521.htm. Accessed December 8, 2008.
• Lacy CF, Armstrong LL, Goldman MP, Lance LL. Lexi-Comp's Drug Information Handbook. 11th ed. Hudson, Ohio: Lexi-Comp, Inc; 2003:1093-1094.
• Uristat Product Information Web site. www.uristat.com/documents/Uristatinsert.pdf. Accessed December 8, 2008.
• Cystex urinary pain relief tablets stop the pain and progression of urinary tract infections (UTIs). Cystex Product Information Web site. www.cystex.com/Pages/About%20Cystex. Accessed December 9, 2008.
• Azo Cranberry Supplement Product Information Web site. www.azoproducts.com/faq/azo_cranberry. Accessed December 8, 2008.
• Hume A, Strong K. Botanical Medicines. In: Berardi RR, Kroon LA, McDermott JH, et al, eds. Handbook of Nonprescription Drugs. 15th ed. Washington, DC: American Pharmacists Association; 2006:1114.
• Urinary Tract Infections in Adults. National Kidney and Urologic Diseases Information Clearinghouse Web site. kidney.niddk.nih.gov/kudiseases/pubs/utiadult. Accessed December 9, 2008.