Hospital acquired pneumonia (Antimicrobial)


For pneumonia presenting more than 3 days into hospital admission, it is important to give broad-spectrum antibiotics which are active against Gram-negative organisms in the first instance. In more severe infection, consider cover for Legionella, Staph aureus, both MSSA and MRSA. Use SIRS criteria for severity assessment.

For glossary of terms see Glossary.

Drug details

Non severe

Co-trimoxazole (oral) 960mg twice daily (reduce dose to 480mg twice daily in renal impairment CrCl 30ml/min or less)
OR Doxycycline (oral) 100mg twice daily

Total IV/oral up to 8 days for clinical responders


Severe - infection with an atypical pathogen is uncommon. If suspected, discuss with Microbiology.

IV aztreonam 1 gram every 8 hours in level 1 and 2 care, 2 gram every 8 hours in level 3 care (ICU) PLUS IV vancomycin refer to NHS Highland vancomycin dosing guidelines

Total IV/oral up to 8 days for clinical responders

Editorial Information

Last reviewed: 25/08/2022

Next review date: 25/08/2025

Author(s): Antimicrobial Management Team.

Version: 2.1

Approved By: TAM Subgroup of ADTC

Reviewer name(s): Alison Macdonald, Area Antimicrobial Pharmacist.

Document Id: AMT160