Intra-abdominal sepsis including hepatobiliary (Antimicrobial)
TAM (Treatments and Medicines) NHS Highland
Timely administration in sepsis is vital, ensure agents covering gram negative pathogens (gentamicin or ciprofloxacin) are given first.
In severe illness, unresponsive to first-line therapy, contact Microbiologist for advice.
Note, due to high oral bioavailability, metronidazole can be given orally as soon as the oral route is established.
For glossary of terms see Glossary.
Drug details
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.