What is the first‑line therapy for uncomplicated cystitis in an elderly woman presenting with dysuria, no fever, and no costovertebral‑angle tenderness?

Treatment of Uncomplicated Cystitis in an Elderly Woman

For an elderly woman presenting with dysuria, no fever, and no costovertebral angle tenderness, first-line therapy is nitrofurantoin 100 mg orally twice daily for 5 days, provided her estimated glomerular filtration rate (eGFR) is ≥30 mL/min/1.73 m². 1, 2, 3

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Diagnostic Confirmation

• Confirm pyuria before initiating antibiotics. The presence of ≥10 white blood cells per high-power field (WBC/HPF) or a positive leukocyte-esterase test, combined with acute urinary symptoms (dysuria, frequency, urgency), establishes the diagnosis of uncomplicated cystitis. 1, 2

• The absence of fever and costovertebral angle tenderness effectively rules out pyelonephritis, allowing short-course oral therapy rather than extended treatment. 1, 4

• Routine urine culture is not required for otherwise healthy elderly women with typical lower urinary tract symptoms and no history of recurrent infections or resistant organisms. 2, 5, 6

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First-Line Antibiotic Options

Preferred Agent: Nitrofurantoin

• Nitrofurantoin 100 mg orally twice daily for 5 days achieves approximately 93% clinical cure and 88% microbiological eradication, with worldwide resistance rates below 1%. 2, 3, 7

• Nitrofurantoin preserves intestinal microbiota better than fluoroquinolones or broad-spectrum agents, thereby reducing the risk of Clostridioides difficile infection and other collateral antimicrobial damage. 2, 3

• Contraindication: Do not use nitrofurantoin when eGFR is <30 mL/min/1.73 m² because adequate urinary concentrations cannot be achieved. 2, 3

Alternative First-Line Agents

• Fosfomycin trometamol 3 g as a single oral dose provides approximately 91% clinical cure, maintains therapeutic urinary concentrations for 24–48 hours, and offers the convenience of single-dose administration. 2, 3, 8, 6

  • Fosfomycin is not recommended for pyelonephritis or upper urinary tract infections due to insufficient tissue penetration. 2, 3, 8

• Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg orally twice daily for 3 days achieves 93% clinical cure and 94% microbiological eradication when the pathogen is susceptible. 2, 3, 6

  • Use TMP-SMX only when local E. coli resistance is <20% and the patient has not received TMP-SMX in the preceding 3 months. 2, 3, 5, 6

  • Many regions now report TMP-SMX resistance exceeding 20%, necessitating verification of local antibiogram data before selection. 2, 3

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Reserve (Second-Line) Agents

Fluoroquinolones

• Ciprofloxacin 250–500 mg orally twice daily for 3 days or levofloxacin 250–750 mg once daily for 3 days should be reserved exclusively for culture-proven resistant pathogens or documented failure of first-line agents. 2, 3, 5

• Serious adverse effects (tendon rupture, peripheral neuropathy, CNS toxicity) outweigh benefits in uncomplicated cystitis, especially in the elderly. 2, 3

• Global fluoroquinolone resistance exceeds 10% in several regions, reinforcing the need for restriction. 2, 3

Beta-Lactams

• Amoxicillin-clavulanate, cefdinir, or cefpodoxime for 3–7 days achieve only 89% clinical cure and 82% microbiological eradication, which is significantly inferior to first-line agents. 2, 3, 6

• Amoxicillin or ampicillin alone should never be used because global E. coli resistance exceeds 55–67%. 2, 3

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Treatment Duration

• A 5-day course of nitrofurantoin or a 3-day course of TMP-SMX is sufficient for uncomplicated cystitis in elderly patients. 2, 3, 7, 5

• Fosfomycin is given as a single 3 g dose. 2, 3, 8, 6

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When to Obtain Urine Culture

Obtain urine culture and susceptibility testing when any of the following occur:

• Persistent symptoms after completing therapy 2, 5, 6
• Recurrence of symptoms within 2–4 weeks 2, 5, 6
• Fever >38°C, flank pain, or costovertebral angle tenderness suggesting pyelonephritis 2, 4, 5
• Atypical presentation or history of recurrent infections 2, 5, 6

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Management of Treatment Failure

• If symptoms persist at the end of therapy or recur within 2 weeks, obtain a urine culture and susceptibility test immediately. 2, 5, 6

• Switch to a different antibiotic class for a 7-day course (not the original short regimen), assuming resistance to the initial agent. 2, 5

• Consider imaging (ultrasound or CT) if fever persists beyond 72 hours to exclude obstruction or abscess. 2

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Critical Pitfalls to Avoid

• Do not treat asymptomatic bacteriuria in elderly non-catheterized patients, as this promotes resistance without clinical benefit. Asymptomatic bacteriuria occurs in 15–50% of elderly individuals. 1, 2, 5

• Do not prescribe TMP-SMX without confirming that local E. coli resistance is <20%; failure rates rise sharply above this threshold. 2, 3, 5, 6

• Do not use nitrofurantoin for suspected pyelonephritis or when eGFR is <30 mL/min/1.73 m². 2, 3

• Avoid empiric fluoroquinolones as first-line therapy despite high efficacy, because of serious adverse effects and the need to preserve these agents for complicated infections. 2, 3, 5

• Do not use amoxicillin or ampicillin alone due to very high resistance rates. 2, 3

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Patient Education and Follow-Up

• Instruct the patient to complete the full antibiotic course even if symptoms resolve early. 2

• Advise the patient to return if symptoms persist beyond 48–72 hours, if fever develops, or if flank pain occurs. 2, 4

• No routine post-treatment urinalysis or culture is needed for asymptomatic patients who have completed therapy successfully. 2, 5