NICE urinary tract infection (lower): antimicrobial prescribing

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Urinary tract infection (lower): antimicrobial prescribing. Download a PDF of this algorithm.

Table 1 Antibiotics for non-pregnant women aged 16 years and over
Antibiotic*	Dosage and course length^†
First choice^‡
Nitrofurantoin – if eGFR ≥45 ml/minute^§	100 mg modified-release twice a day for 3 days
Trimethoprim – if low risk of resistance^\|	200 mg twice a day for 3 days
Second-choice (no improvement in lower UTI symptoms on first-choice taken for at least 48 hours, or when first-choice not suitable)^‡,¶
Nitrofurantoin—if eGFR ≥45 ml/minute^§ and not used as first-choice	100 mg modified-release twice a day for 3 days
Pivmecillinam (a penicillin)	400 mg initial dose, then 200 mg three times a day for a total of 3 days
Fosfomycin	3 g single dose sachet
* See BNF for appropriate use and dosing in specific populations, for example, hepatic impairment, renal impairment and breastfeeding ^† Doses given are by mouth using immediate-release medicines, unless otherwise stated ^‡ Check any previous urine culture and susceptibility results and antibiotic prescribing and choose antibiotics accordingly ^§ May be used with caution if eGFR 30–44 ml/minute to treat uncomplicated lower UTI caused by suspected or proven multidrug resistant bacteria and only if potential benefit outweighs risk (BNF, August 2018) ^\| A lower risk of resistance may be more likely if not used in the past 3 months, previous urine culture suggests susceptibility (but this was not used), and in younger people in areas where local epidemiology data suggest resistance is low. A higher risk of resistance may be more likely with recent use and in older people in residential facilities ^¶ If there are symptoms of pyelonephritis or the person has a complicated UTI (associated with a structural or functional abnormality, or underlying disease, which increases the risk of a more serious outcome or treatment failure), see the recommendations on choice of antibiotic in the NICE guideline on pyelonephritis (acute): antimicrobial prescribing.
eGFR=estimated glomerular filtration rate.

Table 2 Antibiotics for pregnant women aged 12 years and over
Antibiotic*	Dosage and course length^†
Treatment of lower UTI
First choice^‡
Nitrofurantoin (avoid at term)—if eGFR ≥45 ml/minute^§,\|	100 mg modified-release twice a day for 7 days
Second-choice (no improvement in lower UTI symptoms on first-choice taken for at least 48 hours or when first-choice not suitable)^‡,¶
Amoxicillin (only if culture results available and susceptible)	500 mg three times a day for 7 days
Cefalexin	500 mg twice a day for 7 days
Alternative second-choices	Consult local microbiologist, choose antibiotics based on culture and susceptibility results
Treatment of asymptomatic bacteriuria
Choose from nitrofurantoin^§,\|, amoxicillin or cefalexin based on recent culture and susceptibility results
* See BNF for appropriate use and dosing in specific populations, for example, hepatic impairment and renal impairment † Doses given are by mouth using immediate-release medicines, unless otherwise stated ‡ Check any previous urine culture and susceptibility results and antibiotic prescribing and choose antibiotics accordingly § Avoid at term in pregnancy; may produce neonatal haemolysis (BNF, August 2018) \| May be used with caution if eGFR 30–44 ml/minute to treat uncomplicated lower UTI caused by suspected or proven multidrug resistant bacteria and only if potential benefit outweighs risk (BNF, August 2018) ¶ If there are symptoms of pyelonephritis or the person has a complicated UTI (associated with a structural or functional abnormality, or underlying disease, which increases the risk of a more serious outcome or treatment failure), see the recommendations on choice of antibiotic in the NICE guideline on pyelonephritis (acute): antimicrobial prescribing.
eGFR=estimated glomerular filtration rate.

Table 3 Antibiotics for men aged 16 years and over
Antibiotic^*	Dosage and course length^†
First choice^‡
Trimethoprim	200 mg twice a day for 7 days
Nitrofurantoin – if eGFR ≥45 ml/minute^§,\|	100 mg modified-release twice a day for 7 days
Second-choice (no improvement in UTI symptoms on first-choice taken for at least 48 hours or when first-choice not suitable)^‡
Consider alternative diagnoses and follow recommendations in the NICE guidelines on pyelonephritis (acute): antimicrobial prescribing or prostatitis (acute): antimicrobial prescribing, basing antibiotic choice on recent culture and susceptibility results.
* See BNF for appropriate use and dosing in specific populations, for example, hepatic impairment and renal impairment † Doses given are by mouth using immediate-release medicines, unless otherwise stated ‡ Check any previous urine culture and susceptibility results and antibiotic prescribing and choose antibiotics accordingly § Nitrofurantoin is not recommended for men with suspected prostate involvement because it is unlikely to reach therapeutic levels in the prostate \| May be used with caution if eGFR 30–44 ml/minute to treat uncomplicated lower UTI caused by suspected or proven multidrug resistant bacteria and only if potential benefit outweighs risk (BNF, August 2018).
eGFR=estimated glomerular filtration rate.

Table 4 Antibiotics for children and young people under 16 years
Antibiotic^*	Dosage and course length^†
Children under 3 months
Refer to paediatric specialist and treat with intravenous antibiotics in line with the NICE guideline on fever in under 5s.
Children aged 3 months and over
First choice^‡,§
Trimethoprim—if low risk of resistance^\|	3 to 5 months, 4 mg/kg (maximum 200 mg per dose) or 25 mg twice a day for 3 days 6 months to 5 years, 4 mg/kg (maximum 200 mg per dose) or 50 mg twice a day for 3 days 6 to 11 years, 4 mg/kg (maximum 200 mg per dose) or 100 mg twice a day for 3 days 12 to 15 years, 200 mg twice a day for 3 days
Nitrofurantoin—if eGFR ≥45 ml/ minute^¶	3 months to 11 years, 750 micrograms/kg four times a day for 3 days 12 to 15 years, 50 mg four times a day or 100 mg modified-release twice a day for 3 days
Second-choice (no improvement in lower UTI symptoms on first-choice taken for at least 48 hours or when first-choice not suitable)^{‡, §, }**
Nitrofurantoin – if eGFR ≥45 ml/ minute^¶ and not used as first-choice	3 months to 11 years, 750 micrograms/kg four times a day for 3 days 12 to 15 years, 50 mg four times a day or 100 mg modified-release twice a day for 3 days
Amoxicillin (only if culture results available and susceptible)	1 to 11 months, 125 mg three times a day for 3 days 1 to 4 years, 250 mg three times a day for 3 days 5 to 15 years, 500 mg three times a day for 3 days
Cefalexin	3 to 11 months, 12.5 mg/kg or 125 mg twice a day for 3 days 1 to 4 years, 12.5 mg/kg twice a day or 125 mg three times a day for 3 days 5 to 11 years, 12.5 mg/kg twice a day or 250 mg three times a day for 3 days 12 to 15 years, 500 mg twice a day for 3 days
* See BNF for children (BNFC) for appropriate use and dosing in specific populations, for example, hepatic and renal impairment. See table 2 if a young woman is pregnant † The age bands apply to children of average size and, in practice, the prescriber will use the age bands in conjunction with other factors such as the severity of the condition being treated and the child’s size in relation to the average size of children of the same age. Doses given are by mouth using immediate-release medicines, unless otherwise stated ‡ Check any previous urine culture and susceptibility results and antibiotic prescribing and choose antibiotics accordingly. Where a child or young person is receiving prophylactic antibiotics, treatment should be with a different antibiotic, not a higher dose of the same antibiotic § If 2 or more antibiotics are appropriate, choose the antibiotic with the lowest acquisition cost. Some children may also be able to take a tablet or part-tablet, rather than a liquid formulation, if the dose is appropriate \| A lower risk of resistance may be more likely if not used in the past 3 months, previous urine culture suggests susceptibility (but this was not used), and in younger people in areas where local epidemiology data suggest resistance is low. A higher risk of resistance may be more likely with recent use and in older people in residential facilities ¶ May be used with caution if eGFR 30–44 ml/minute to treat uncomplicated lower UTI caused by suspected or proven multidrug resistant bacteria and only if potential benefit outweighs risk (BNFC, August 2018) ** If there are symptoms of pyelonephritis or the person has a complicated UTI (associated with a structural or functional abnormality, or underlying disease, which increases the risk of a more serious outcome or treatment failure), see the recommendations on choice of antibiotic in the NICE guideline on pyelonephritis (acute): antimicrobial prescribing.
eGFR=estimated glomerular filtration rate.

Managing lower urinary tract infection

Be aware that lower urinary tract infection (UTI) is an infection of the bladder usually caused by bacteria from the gastrointestinal tract entering the urethra and travelling up to the bladder
Give advice about managing symptoms with self-care (see the recommendations on self-care) to all people with lower UTI

Treatment for women with lower UTI who are not pregnant

Consider a back-up antibiotic prescription (to use if symptoms do not start to improve within 48 hours or worsen at any time) or an immediate antibiotic prescription (see the recommendations on choice of antibiotic) for women with lower UTI who are not pregnant. Take account of:
- the severity of symptoms
- the risk of developing complications, which is higher in people with known or suspected structural or functional abnormality of the genitourinary tract or immunosuppression
- the evidence for back-up antibiotic prescriptions, which was only in non-pregnant women with lower UTI where immediate antibiotic treatment was not considered necessary
- previous urine culture and susceptibility results
- previous antibiotic use, which may have led to resistant bacteria
- preferences of the woman for antibiotic use
If a urine sample has been sent for culture and susceptibility testing and an antibiotic prescription has been given:
- review the choice of antibiotic when microbiological results are available, and
- change the antibiotic according to susceptibility results if bacteria are resistant and symptoms are not already improving, using a narrow-spectrum antibiotic wherever possible

Treatment for pregnant women and men with lower UTI

Offer an immediate antibiotic prescription (see the recommendations on choice of antibiotic) to pregnant women and men with lower UTI. Take account of:
- previous urine culture and susceptibility results
- previous antibiotic use, which may have led to resistant bacteria
Obtain a midstream urine sample from pregnant women and men before antibiotics are taken, and send for culture and susceptibility testing
For pregnant women with lower UTI:
- review the choice of antibiotic when microbiological results are available, and
- change the antibiotic according to susceptibility results if the bacteria are resistant, using a narrow-spectrum antibiotic wherever possible
For men with lower UTI:
- review the choice of antibiotic when microbiological results are available, and
- change the antibiotic according to susceptibility results if the bacteria are resistant and symptoms are not already improving, using a narrow-spectrum antibiotic wherever possible

Treatment for children and young people under 16 years with lower UTI

Obtain a urine sample from children and young people with lower UTI before antibiotics are taken, and dipstick test or send for culture and susceptibility testing in line with the NICE guideline on urinary tract infection in under 16s
Assess and manage children under 5 with lower UTI who present with fever as outlined in the NICE guideline on fever in under 5s
Offer an immediate antibiotic prescription (see the recommendations on choice of antibiotic) for children and young people under 16 years with lower UTI. Take account of:
- previous urine culture and susceptibility results
- previous antibiotic use, which may have led to resistant bacteria
If a urine sample has been sent for culture and sensitivity testing when an antibiotic prescription has been given:
- review the choice of antibiotic when microbiological results are available, and
- change the antibiotic according to susceptibility results if the bacteria are resistant and symptoms are not already improving, using a narrow-spectrum antibiotic wherever possible

Advice for all people with lower UTI when an antibiotic prescription is given

When a back-up antibiotic prescription is given, as well as the general advice on self-care, give advice about:
- an antibiotic not being needed immediately
- using the back-up prescription if symptoms do not start to improve within 48 hours or if they worsen at any time
- possible adverse effects of antibiotics, particularly diarrhoea and nausea
- seeking medical help if antibiotics are taken and:
  - symptoms worsen rapidly or significantly at any time, or
  - symptoms do not start to improve within 48 hours of taking the antibiotic, or
  - the person becomes systemically very unwell
When an immediate antibiotic prescription is given, as well as the general advice on self-care, give advice about:
- possible adverse effects of the antibiotic, particularly diarrhoea and nausea
- seeking medical help if symptoms worsen rapidly or significantly at any time, do not start to improve within 48 hours of taking the antibiotic, or the person becomes systemically very unwell

Reassessment

Reassess if symptoms worsen rapidly or significantly at any time, or do not start to improve within 48 hours of taking the antibiotic, taking account of:
- other possible diagnoses
- any symptoms or signs suggesting a more serious illness or condition, such as pyelonephritis
- previous antibiotic use, which may have led to resistant bacteria
  
  Send a urine sample for culture and susceptibility testing if this has not already been done and review treatment when results are available

Referral

Refer people aged 16 years and over with lower UTI to hospital if they have any symptoms or signs suggesting a more serious illness or condition (for example, sepsis)
Refer children or young people with lower UTI to hospital in line with the NICE guideline on urinary tract infection in under 16s

Managing asymptomatic bacteriuria

Be aware that asymptomatic bacteriuria:
- is significant levels of bacteria (greater than 10⁵ colony forming units/ml) in the urine with no symptoms of UTI
- is not routinely screened for, or treated, in women who are not pregnant, men, young people and children
- is routinely screened for, and treated with antibiotics, in pregnant women because it is a risk factor for pyelonephritis and premature delivery (see the recommendations on choice of antibiotic)
Offer an immediate antibiotic prescription to pregnant women with asymptomatic bacteriuria, taking account of:
- recent urine culture and susceptibility results
- previous antibiotic use, which may have led to resistant bacteria

Self-care

Advise people with lower UTI about using paracetamol for pain, or if preferred and suitable ibuprofen
Advise people with lower UTI about drinking enough fluids to avoid dehydration
Be aware that no evidence was found on cranberry products or urine alkalinising agents to treat lower UTI

Choice of antibiotic

When prescribing antibiotic treatment for lower UTI, take account of local antimicrobial resistance data and follow:
- table 1 for non-pregnant women aged 16 years and over
- table 2 for pregnant women aged 12 years and over
- table 3 for men aged 16 years and over
- table 4 for children and young people under 16 years

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NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication.

Published date: October 2018.