1st Line
See ward poster for sequence of drug administration

IV gentamicin - refer to NHS Highland gentamicin guidelines

PLUS IV amoxicillin 1g 3 times daily

PLUS IV metronidazole 500mg 3 times daily - see note about early switch to oral metronidazole

7 to 10 days

For infections arising within 24 hours of surgery where gentamicin has been given as part of surgical prophylaxis substitute.
IV aztreonam 1 gram every 8 hours - dose can increase if severely unwell for gentamicin.

1st line if Penicillin allergy

IV ciprofloxacin 400mg IV every 8 hours (see BNF warnings and MHRA Drug Safety Alert (updated 22 January 2024))

PLUS IV vancomycin - refer to NHS Highland vancomycin guidelines

PLUS IV metronidazole 500mg 3 times daily - see note above about early switch to oral metronidazole

7 to 10 days

Where vancomycin cannot be used, substitute with teicoplanin and follow the doses for use in infections with sepsis.

If no positive Microbiology result, step down to oral.
If a pathogen has been isolated, therapy should be targeted against that organism with advice from Microbiology as necessary.

Oral co-trimoxazole 960mg twice daily

PLUS oral metronidazole 400mg 3 times daily

7 to 10 days

Cautions for co-trimoxazole use: in renal impairment or in combination with other drugs which promote hyperkalaemia, monitor potassium levels if used for longer than 3 days.

In renal impairment (CrCl 30ml/min or less)

Oral co-trimoxazole 480mg twice daily

PLUS oral metronidazole 400mg three times daily

7 to 10 days

Cautions for co-trimoxazole use: in renal impairment or in combination with other drugs which promote hyperkalaemia, monitor potassium levels if used for longer than 3 days.