Parenteral route of administration for antimicrobials

Parenteral antimicrobial administration (usually intravenous, but occasionally intramuscular or intraosseous if intravenous access is difficult) is required when:

• urgent treatment is required for severe and rapidly progressing infection
• higher doses than can be administered or tolerated orally are required to achieve an effective concentration at the site of infection (eg meningitis, endocarditis)
• oral administration is not tolerated or not possible
• gastrointestinal absorption is likely to be significantly reduced (eg vomiting, gastrointestinal pathology)
• there is no oral antimicrobial with a suitable spectrum of activity.

The use of extended or continuous infusions of antimicrobials may be appropriate in certain circumstances to ensure adequate drug exposure (eg in patients with septic shock, patients requiring intensive care support). Continuous infusions may also be appropriate for Ambulatory antimicrobial therapy.