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Recurrent uncomplicated lower urinary tract infection in a non-pregnant woman — MSRA MCQ

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HardUrinary Tract InfectionsRecurrent uncomplicated lower urinary tract infection in a non-pregnant womanMSRA

A 42-year-old non-pregnant woman seeks prevention of recurrent urinary tract infection (UTI). She has had four culture-confirmed episodes of Escherichia coli lower UTI in the past 10 months. Each caused dysuria and frequency without fever, rigors, loin pain, vomiting or visible haematuria, and resolved with culture-directed treatment. She is currently asymptomatic. There is no relationship to sexual intercourse or another identifiable trigger. She has no symptoms of genitourinary syndrome of menopause, urinary tract abnormality, renal stones, catheter use or diabetes. Increased fluid intake and avoiding delayed voiding have not reduced recurrence. She wishes to avoid continuous antibiotic prophylaxis if possible. Her eGFR is 72 mL/minute/1.73 m², liver function is normal, and she is not taking a sulfonamide. She uses over-the-counter potassium citrate sachets whenever she develops urinary discomfort. What is the most appropriate prophylactic management now?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Stop potassium citrate and start methenamine hippurate 1 g twice daily, with review within 6 months

Explanation lettering: D = shown as A · C = shown as B · E = shown as C · A = shown as D · B = shown as E

This woman has recurrent uncomplicated lower UTI, is currently infection-free, is not pregnant, and has not improved with behavioural measures. Vaginal oestrogen is not indicated because she has no symptoms of genitourinary syndrome of menopause, and single-dose antibiotic prophylaxis is unsuitable because there is no identifiable trigger. NICE therefore supports methenamine hippurate as an alternative to daily antibiotic prophylaxis. The recommended adult prophylactic dose is 1 g twice daily, with review within 6 months. Potassium citrate must be stopped: it alkalinises urine and can reduce methenamine’s effectiveness. Methenamine requires acidic urine to generate its urinary antibacterial activity. Her renal function and absence of sulfonamide treatment do not introduce the key prescribing contraindications described in the SmPC. A is inappropriate because there is no predictable trigger for single-dose prophylaxis. C is a reasonable later option if methenamine is ineffective or unsuitable, but NICE places daily antibiotic prophylaxis after appropriate non-antibiotic and targeted strategies. D fails because concurrent potassium citrate can make methenamine less effective. E is unnecessary: specialist advice is recommended for methenamine in pregnancy, men, children, recurrent upper UTI or complicated lower UTI, none of which applies here.

Reference: NICE NG112: Urinary tract infection (recurrent): antimicrobial prescribing — Recommendations (Last updated 12 December 2024) — https://www.nice.org.uk/guidance/ng112/chapter/recommendations Hiprex 1 g Tablets — Summary of Product Characteristics (Updated 2025) — https://www.medicines.org.uk/emc/product/1530/smpc