How to Choose an Antibiotic
Before deciding whether to prescribe an antibiotic there are a number of
things to consider and questions to ask. Firstly:
• Make sure you know normal flora and the causes of common infections
• Know your specialities serious and common infections, the micro-organisms that cause these and the usual treatments for them
• Use the British National Formulary (BNF) for interactions, cautions and contraindications as well as dosing information
• Discuss patients with your own senior team members and Consultant
• Know your own hospital’s empirical antibiotic guidelines for your specialty
Empirical antibiotic guidelines are established by answering many of the
questions below. It is essential to understand the relevance of these questions
and the effect of the answers. Relying on empirical antibiotic guidelines
without knowing why or how these guidelines are produced can be dangerous and is
poor practice.
things to consider and questions to ask. Firstly:
• Make sure you know normal flora and the causes of common infections
• Know your specialities serious and common infections, the micro-organisms that cause these and the usual treatments for them
• Use the British National Formulary (BNF) for interactions, cautions and contraindications as well as dosing information
• Discuss patients with your own senior team members and Consultant
• Know your own hospital’s empirical antibiotic guidelines for your specialty
Empirical antibiotic guidelines are established by answering many of the
questions below. It is essential to understand the relevance of these questions
and the effect of the answers. Relying on empirical antibiotic guidelines
without knowing why or how these guidelines are produced can be dangerous and is
poor practice.
Prophylaxis vs. Treatment
Prophylaxis is the use of antibiotics to prevent infection of a previously uninfected site.
Primary Prophylaxis
• Aims to prevent initial infection e.g. surgical prophylaxis
• Duration – prophylactic antibiotics usually required for <24 hours
• Only required whilst ongoing entry of bacteria into sterile body sites e.g. at the time of surgery
Secondary Prophylaxis
• Aims to prevent recurrent episodes of infection
• Duration – usually long courses of antibiotics at reduced doses e.g. post-splenectomy, rheumatic fever, recurrent UTIs in children
Treatment
Treatment is the use of antibiotics to eliminate infection from an already infected site. Treatment and duration of treatment varies between clinical conditions (see section - Clinical Scenarios for individual conditions).
Primary Prophylaxis
• Aims to prevent initial infection e.g. surgical prophylaxis
• Duration – prophylactic antibiotics usually required for <24 hours
• Only required whilst ongoing entry of bacteria into sterile body sites e.g. at the time of surgery
Secondary Prophylaxis
• Aims to prevent recurrent episodes of infection
• Duration – usually long courses of antibiotics at reduced doses e.g. post-splenectomy, rheumatic fever, recurrent UTIs in children
Treatment
Treatment is the use of antibiotics to eliminate infection from an already infected site. Treatment and duration of treatment varies between clinical conditions (see section - Clinical Scenarios for individual conditions).
Antibiotic Spectrum of activity
Click for larger image
How to Prescribe an Antibiotic
• Name of Antibiotic
- This should be the generic name, not a specific product name
• Indication
- In order to know if the stop date is correct, you need to know why the antibiotic has been prescribed
• Start Date
- This is the date the antibiotic was first prescribed NOT the date the prescription was re-written
• Frequency of Dosing
- Antibiotics need to be spaced out evenly in order to maintain therapeutic levels in a patient
• Stop or Review Date
- Should be set at the time of prescribing based on the original diagnosis, e.g. CAP is
diagnosed and treated for 7 days
• Signature
• Name
• GMC number
- This should be the generic name, not a specific product name
• Indication
- In order to know if the stop date is correct, you need to know why the antibiotic has been prescribed
• Start Date
- This is the date the antibiotic was first prescribed NOT the date the prescription was re-written
• Frequency of Dosing
- Antibiotics need to be spaced out evenly in order to maintain therapeutic levels in a patient
• Stop or Review Date
- Should be set at the time of prescribing based on the original diagnosis, e.g. CAP is
diagnosed and treated for 7 days
• Signature
• Name
• GMC number
