Recurrent UTI

Definition: 2 or more infections in 6 months, or 3 or more in 12 months.

Recurrent UTI in men requires urological evaluation — commonly caused by chronic bacterial prostatitis. See uti.md for acute cystitis/pyelonephritis management and vesicoureteral-reflux.md for the paediatric-specific approach.

Behavioural measures

Increase fluid intake (>1.5L/day above baseline) — thought to work by diluting bladder bacterial concentration. Front-to-back wiping and post-coital urination are commonly advised, though evidence is weak — low risk, so reasonable to mention, but shouldn’t be the central focus of counselling, and patients should be reassured hygiene isn’t “to blame.”

Non-antibiotic prevention — evidence by option

Option	Evidence level	Guideline stance	Notes
Vaginal topical oestrogen	1b	Recommended	Reduces rUTI in postmenopausal women by depleting vaginal glycogen/flora; despite common misconceptions, is supported for this use — not associated with the cardiovascular/cancer risks of systemic HRT
Methenamine hippurate (Hiprex)	1b	Recommended	Hydrolysed to formaldehyde in the bladder; non-inferior to daily low-dose antibiotic prophylaxis (2022 ALTAR trial) with a better safety profile and no resistance development over time. Not effective with renal tract abnormalities or neuropathic bladder. Long-term benefit is limited — recurrence rate matches placebo after 1 year
Cranberry	1a	Consider	Efficacious in women and children only; no standardised dose/duration, limited comparison between forms (juice vs supplement)
D-mannose	2	Consider	Contradictory evidence, no standardised dosing, lacks high-quality RCTs
Probiotics (e.g. Lactobacillus)	1b	Not supported	No significant benefit over placebo in adequately conducted studies
Intravesical glycosaminoglycan (hyaluronic acid, chondroitin sulfate)	2	Consider	Two RCTs show promise (reduced recurrence, longer symptom-free interval, better QoL) but more research needed; requires catheterisation
Immunoactive agents/vaccines (OM-89, MV140, StroVac)	1a	Recommended	Bacterial-extract vaccines via oral, vaginal pessary, or injectable routes; more effective than placebo, but availability in Australia is restricted and requires urologist-coordinated access

Antibiotic prophylaxis

• Trimethoprim 150mg nocte, cephalexin 250mg nocte, or nitrofurantoin 50mg nocte
• Alternatively, a single dose of the above taken within 2 hours after sex
• Use for 6 months then cease; seek urology advice if UTIs recur despite prophylaxis
• Long-term nitrofurantoin is associated with pulmonary toxicity, hepatotoxicity and peripheral neuropathy (more common with CKD) — monitor LFTs, UECs, and consider PFTs
• Patient-initiated treatment (started by the patient at symptom onset) reduces overall antibiotic use compared with continuous prophylaxis and may be a suitable alternative
• Advise review if symptoms don’t resolve within 48 hours of starting treatment