Good practice recommendations for antimicrobial use in frail older people


To provide recommendations for healthcare professionals on the safe, effective and rational use of antimicrobials in frail elderly people in both hospital and community settings, including care homes.


“Frail” in this context refers to people who have a reduced in-built reserve resulting in increased risk of poorer health outcomes [1,2]. Frailty is more common in people aged 65 and older. People over 75 are twice as likely to be prescribed antimicrobials compared to those aged 55 and under. For those aged over 90 this increases to three times more likely [3].

The risks of using antibiotics in frail older people include Clostridioides difficile infection (CDI) and increased risk of antimicrobial resistance. In addition polypharmacy (prescribing or taking of too many medicines) increases the risk of adverse drug events, hospital admissions, health care costs and non-adherence. These risks should be balanced against the risks of potentially under treating an infection if antimicrobials are not given.

Good practice recommendations

A list of recommendations to be considered when prescribing antimicrobials in frail older people is given below.

It is also important to discuss current and future antibiotic prescribing decisions with the patient and their care team as part of anticipatory care planning conversations, and to document these decisions in the clinical notes and in the patient’s Key Information Summary.

Further information on shared decision making can be found via Realistic Medicine website and Shared decision making (NICE guideline NG197) (


  • Current local empirical antimicrobial guidelines should be available in all healthcare settings eg wards, clinics, GP practices, out-of-hours services, community nursing bases, community pharmacies, hospices and adult care homes.
  • User-friendly guidance to support diagnosis of infection should be available in all settings eg urinary tract infection (UTI) decision aid, CURB-65 or CRB-65 scores, sepsis recognition and severity assessment, management of CDI and recommended samples for microbiology investigations.

Initiating therapy

  • The decision to start an antimicrobial should take into account documented prescribing decisions within the anticipatory care plan, an assessment of the nature and severity of the suspected infection and the potential clinical benefit of treatment. Co-morbidities, polypharmacy and other concomitant health issues should also be taken into consideration.
  • The use of severity scoring systems may overestimate the severity of suspected infection in frail elderly people. This can result in unnecessary escalation of care. This should be considered when initiating antibiotic treatment.
  • Consider the potential for infections due to resistant organisms. Confirm details of previous infections and treatment within the last 12 weeks in the patient record and use this to inform antimicrobial therapy.
  • In ‘end of life’ care or when an anticipatory care plan is in place, and before acute clinical deterioration, the clinical benefits and risks of antimicrobial therapy should be carefully considered and discussed with the patient and with their carers when appropriate. The agreed plan should be clearly documented. Local palliative care advice should be sought if required. See Good practice recommendations for use of antibiotics towards the end of life.

Prescribing principles

  • Choice of antimicrobial should follow local policy or advice from a local infection specialist.
  • Avoid antimicrobials with a high risk of CDI (cephalosporins, fluoroquinolones, co-amoxiclav, clindamycin) whenever possible. Proton pump inhibitors (omeprazole, lansoprazole, esomeprazole) are also associated with an increased risk of CDI.
  • Use the oral route wherever possible. If the intravenous route is used due to severity of infection or inability to swallow, switch to oral therapy as soon as possible.
  • Exercise caution when prescribing fluoroquinolones due to higher risks of tendon injury and other adverse events. Refer to MHRA advice for further information. However, potential fluoroquinolone risks should be balanced against the risks of using alternative agents. Scottish Antimicrobial Prescribing Group (SAPG) advises that it is reasonable to prefer oral fluoroquinolones over broader spectrum or intravenous agents, particularly if this supports earlier intravenous to oral switch or hospital discharge.
  • Check potential drug interactions due to polypharmacy in the current British National Formulary (BNF).
  • Monitor for adverse effects of medication. The risk of adverse events caused by altered pharmacokinetics of medicines is increased in older people due to low body weight, impaired absorption, altered drug distribution (increase in body fat, decrease in total body water), and reduced clearance.
  • Dehydration is common in older people, especially when unwell, and should be considered when interpreting estimated Glomerular Filtration Rates (eGFR) or serum creatinine results.
  • Adjust antimicrobial dosage in the presence of chronic kidney disease to avoid adverse effects and follow advice in the current BNF.
  • Specific advice for antimicrobial use in renal impairment include the following:
    • Nitrofurantoin may be used, with caution, as short course therapy to treat uncomplicated UTI if eGFR is 30 to 44 mL/minute. Treatment should be for 3 days in women and 7 days in men.
    • Calculate gentamicin and vancomycin initial doses, adjust doses as necessary and monitor treatment response.

Monitoring treatment response

  • Monitor response to antimicrobial therapy regularly (daily in hospital settings) to assess resolution of symptoms eg temperature returned to normal, increased energy, alertness, mobility and appetite.
  • Identify adverse effects such as nausea and vomiting, diarrhoea, skin rash. Lack of response after 48 hours of treatment and adverse effects should be highlighted to medical staff.
  • Review microbiology results when available to ensure antimicrobial therapy is suitable and de-escalate to narrower spectrum agents as soon as possible.
  • Use the shortest effective duration of antimicrobial therapy to minimise adverse events and antimicrobial resistance. Duration should follow local policy or advice from a local infection specialist.
  • Ensure that the prescription is discontinued once the course is complete.

Specific advice on managing common infections

Urinary tract infections

  • Urine dipstick is not recommended for diagnosis of UTI in women over 65.
  • Urine samples should only be sent for culture if elderly patients present with urinary symptoms or systemic signs of infection. Do not treat elderly female patients for UTI if they have bacteria in their urine but do not have symptoms of UTI.

 Recurrent urinary tract infections

  • Recurrent UTI is defined as two episodes within 6 months or three episodes within 12 months.
  • In elderly females with recurrent UTI, consider non-antibiotic approaches eg topical oestrogen or methenamine (where available and with appropriate follow up and monitoring for toxicity) to reduce risk of recurrent UTIs and need for future antibiotic therapy.
  • Published data support the use of cranberry products to reduce the risk of symptomatic, UTIs which have been confirmed by urine cultures in women with recurrent UTIs however the available evidence does not support its use specifically in the elderly.
  • Alternatively, a 3-to-6-month trial of nightly antimicrobial prophylaxis following local antimicrobial guidelines may be considered. There is no evidence supporting longer term use of prophylactic antimicrobials as it promotes emergence of resistant organisms and increases the risk of infections that may be difficult to treat.

 Respiratory tract infections

  • The majority of respiratory infections are self limiting, including those in older people. Purulent (green or brown) sputum may suggest pneumonia or bacterial infective exacerbation of chronic obstructive pulmonary disease and antibiotics are required for these infections.

Table of abbreviations

BNF British National Formulary
CDI Clostridioides difficile infection
CURB-65 A tool to estimate mortality of community-acquired pneumonia and guide treatment decisions. It uses five criteria: confusion, urea, respiratory rate, blood pressure and if you are age over 65. Where blood levels are not available and it is not possible to obtain urea measurements the abbreviated CRB-65 can be used
eGFR estimated Glomerular Filtration Rates
MHRA Medicines and Healthcare products Regulatory Agency
NICE National Institute for Health and Care Excellence
UTI Urinary tract infection
SAPG Scottish Antimicrobial Prescribing Group


Scottish Antimicrobial Prescribing Group (SAPG) | Feb 2024 for review Feb 2027
Content updated: April 2024