This guidance is intended to assist medical staff to make a rational choice of an antimicrobial before drug sensitivities are known.

It takes into account national and local guidelines and local sensitivities. Reference should also be made to guidelines for specialist areas.

The guidance refers to the treatment of adult patients.

Doses quoted are for patients with normal renal function unless otherwise stated.

Prudent Antimicrobial Prescribing

When choosing Antimicrobials consider:

1. Choice

• The likely organisms causing the infection
• Allergies and contra-indications
• Interactions with other drugs. The current BNF and the drug manufacturer’s Summary of Product Characteristics (www.medicines.org.uk) provide details of interactions and their significance. Specialist advice on alternatives may need to be sought if a particular drug combination is contra-indicated.
• Previous antimicrobial therapy
• Antimicrobial likely to achieve adequate concentrations at site of infection?
• Change according to culture and sensitivities
• Site of infection
• Severity
• Age, weight, renal and hepatic function of the patient
• Consider oral route if appropriate for the patient
• Reassess IV route within 48 hours. Choose oral antibiotic according to guideline or according to sensitivities.

2. Duration

• According to guidelines.  Otherwise keep to 5 days and then review
• Always indicate a stop date or course length in the drug kardex and patient case notes
• Remember antimicrobials must be given regularly, e.g. every 6 hours or 8 hours

The most current version of the British National Formulary provides general guidance on prescribing and prescription writing.