Adult Uncomplicated UTI i.e. no fever or flank pain

Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Board website or the printed Irish Medicines Formulary for drug SPCs, dosage, contraindications, interactions, or IMF/BNF/BNFC/MIMS. See guidance on dosing in children for quick reference dosage/weight guide.

Letters indicate strength of evidence range from A+ (systematic review) to D (informal opinion). Statins can interact with some antibiotics and increase the risk of rhabdomyolysis. Amiodarone and drugs which prolong the QT interval can interact with many antibiotics. Many antibiotics increase the risk of bleeding with anticoagulants. Please refer to our Drug Interactions Table for further information.

Comments from Expert Advisory Committee

  • Use urine dipstick to exclude UTI: negative nitrite and negative leucocyte has a 95% negative predictive value. Always send pre-treatment MSU in males.
  • Choice of empirical therapy should be governed by local resistance rates where available. Patterns can vary substantially across the country. For first presentations, with low risk of resistant organisms in uncomplicated UTI consider narrow-spectrum antibiotics that concentrate in the bladder such as fosfomycin or nitrofurantoin or trimethoprim .
  • Community multi-resistant E. coli with extended-spectrum Betalactamase enzymes are increasing so perform culture in all treatment failures. ESBLs are multi-resistant but often remain sensitive to nitrofurantoin and fosfomycin. There is less relapse with trimethoprim than cephalosporins.
  • Fosfomycin has been introduced as a first line choice for treatment of Uncomplicated UTI in women only.  To preserve the efficacy of this drug, its use should be limited where possible to the recommendation in these guidelines , i.e Uncomplicated UTI in women, or in specific situations on advice of an infection specialist.  This antibiotic should be avoided in the elderly and in patients with renal impairment due to diminished urinary concentrations.  Recommendation for use in pregnancy remains under review pending further evidence and safety data.
  • Fosfomycin is not recommended for use for treatment of UTI in Patients > 65 years in Long Term Care Facilities except in specific situations on advice of an infection specialist. Please refer to the relevant section in these guidelines for treatment of UTI in Patients > 65 years in Long Term Care Facilities

  • Both fosfomycin and nitrofurantoin should be avoided in renal impairment due to diminished urinary concentrations and increased risk of toxicity.


Treatment Dose TX Duration
nitrofurantoin A- 50mg QDS 3 days, (7 days in men)
OR trimethoprim A- 200mg BD 3 days, (7 days in men)

OR fosfomycin*

3g STAT (Females only)
*please see above for where to avoid unless microbiologist advised
Consider the following agents for empiric therapy where appropriate - based on local resistance rates: cephalexin or co-amoxiclav. Amoxicillin resistance is common – only use if susceptibility data available . For uncomplicated UTI reserve quinolones for resistant infections with limited options and confirmed by results of culture and sensitivity.

Patient Information

The HSE Health A-Z website provides patient information on many hundreds of conditions and treatments.

We recommend patients use the website developed by HSE/ICGP/IPU partnership for tips on how to get better from common infections without using antibiotics, what you can do for yourself or a loved one and when to seek help.

Reviewed December 2017

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