Principles of antibacterial treatment

The Formulary aims to provide a simple, effective, economical and empirical approach to the treatment of common infections, and to minimise the emergence of bacterial resistance in the community.

Advice is based on the Public Health England Management of Infection Guidance for Primary Care, adapted with local specialists.

Professional judgement should be used in the management of infections and patients should be involved in the decision.

Non-prescription / delayed prescription forms to help reduce inappropriate antibiotic prescribing are available from a number of websites (see notes below), an example can be found here.

Principles of Treatment

Where a 'best guess' therapy has failed or special circumstances exist, including the suspicion/ confirmation of MRSA, ESBLs and Clostridium difficile infection, microbiological advice should be obtained from:

Prescribe an antibiotic only when there is likely to be a clear clinical benefit.

It is important to initiate antibiotics as soon as possible in severe infection.

The formulary gives dose and duration of treatment for adults unless stated otherwise, these may need modification for age, weight, liver and renal function. Children's doses are provided for some infections. In severe or recurrent cases consider a larger dose, or longer course, or that treatment failure is due to resistance. Please refer to the BNF for further dosing, cautions and interaction information if needed and please check for hypersensitivity.

The GFR supplied by local laboratories relates to an estimated value for 70kg males. In the obese the true creatinine clearance may be very different and in such instances consider using the Cockcroft-Gault calculation for a better estimate of creatinine clearance

Have a lower threshold for antibiotics in immunocompromised or those with multiple morbidities; consider culture and seeking specialist advice.

Do not prescribe an antibiotic for sore throat, simple coughs and colds. Consider a no, or back-up/ delayed, antibiotic strategy for acute self-limiting upper respiratory tract infections and mild UTI symptoms. Patient information leaflets that support a no prescription or delayed prescription strategy are available from the Royal College of General Practitioners website. Limit prescribing over the telephone to exceptional cases.

Use simple generic antibiotics first line whenever possible. Avoid broad spectrum antibiotics (e.g. co-amoxiclav, quinolones and cephalosporins) when narrow spectrum antibiotics remain effective, as broad spectrum antibiotics increase risk of Clostridium difficile, MRSA and resistant UTIs.

Allergic reactions to penicillins occur in 1-10% of patients. Those with a history of severe allergy, for example, immediate hypersensitivity to penicillins, including urticarial rash and Stevens-Johnson syndrome, may also react to cephalosporins and other beta-lactam antibiotics therefore in severe allergy these should also be avoided.

Avoid widespread use of topical antibiotics, especially those agents also available as systemic preparations e.g. fusidic acid.

In pregnancy, take specimens to inform treatment. Where possible, avoid tetracyclines, aminoglycosides, quinolones, azithromycin (except in chlamydial infection), clarithromycin, and high dose metronidazole (2g stat), unless the benefits outweigh the risks. Penicillins, cephalosporins, and erythromycin are safe in pregnancy. Short-term use of nitrofurantoin is not expected to cause foetal problems (theoretical risk of neonatal haemolysis). Trimethoprim is also unlikely to cause problems unless poor dietary folate intake, or taking another folate antagonist.

Women taking combined hormonal contraceptives: Additional precautions are not required to maintain contraceptive efficacy when using antibiotics that are not enzyme inducers (e.g. not rifampicin-like drugs), unless diarrhoea and vomiting occur. See the latest version of the BNF for full details.

NICE NG143: Fever in under 5s: assessment and initial management provides guidance on the assessment and early management of fever with no obvious cause in children aged under 5.

NICE NG51 provides guidance on the recognition, diagnosis and early management of sepsis for all populations.

NHS Choices also has a useful summary page on sepsis, and the UK Sepsis Trust website provides information and resources for patients and healthcare professionals.


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