Treatment of first episode of CDI

Antimicrobial prescribing: NHS Lothian
NHS Lothian
See Overview for overall care and management.
Treatment may not be required if the patient has an equivocal C. difficile result (see Equivocal result). If ongoing symptoms (e.g. diarrhoea), consider repeat testing and seek infection specialist advice as appropriate.

Review severity markers (see Severity of Infection).

Vancomycin 125 mg every 6 hours orally

Duration = 10 days

If oral route not available give via alternative enteral route.

Review and document severity of disease daily.

Diarrhoea can take one to two weeks to resolve and it is not usually possible to determine whether antibiotic treatment is ineffective until day 7.

For patients who fail to improve after 7 days or worsen with oral vancomycin, discuss with infection specialist and review options for treatment failure below.

Treatment failure

For patients who fail to improve after 7 days or worsen with oral vancomycin discuss with an infection specialist (see How to get advice). Treatment will be dependent on clinical setting/severity of disease. 

Antimicrobial recommendations:

Fidaxomicin 200mg every 12 hours orally

Duration = 10 days

OR

Vancomycin 500 mg every 6 hours orally

Duration = 10 days

Editorial Information

Last reviewed: 01/06/2026

Next review date: 01/06/2029

Version: 3.0

Approved By: Antimicrobial Management Committee