Canterbury DHB


CDHB Antimicrobial Guidelines




The South Canterbury, Taranaki, and West Coast DHBs endorse the Canterbury DHB Pink Book Antimicrobial Guidelines.

These guidelines are for use in ADULT patients only.

Information contained in these guidelines is provided to assist with medicine therapy and should be used in conjunction with pertinent clinical data. Final responsibility for drug use rests with the prescriber.

These guidelines are usually reviewed every two years using relevant international guidelines and consensus documents, and local susceptibility data and expert opinion.

In This Section

Penicillin Allergy

Intravenous Antimicrobial Therapy

General Antimicrobial Advice

Intravenous (IV) to Oral (PO) Switch

Antimicrobial Intravenous to Oral Switch Protocol

Antimicrobial Susceptibilities


Antimicrobial Dosing Guidelines (Adults) – Gentamicin/Tobramycin and Vancomycin

Bone and Joint

Cardiovascular System

Central Nervous System

Ear, Nose and Throat


Gastrointestinal System

Methicillin Resistant S. aureus (MRSA)

Obstetrics and Gynaecology

Respiratory System


Sexually Transmitted Infections

Skin and Soft Tissue

Urinary Tract Infections


Penicillin Allergy

See Adverse Reactions to Penicillins in Adults on Hospital HealthPathways.

Intravenous Antimicrobial Therapy

Patients should be started on intravenous (IV) antimicrobials if they fulfil any of these indications:

Some antimicrobials have high oral availability and are tolerated at high oral doses.

General Antimicrobial Advice

Intravenous (IV) to Oral (PO) Switch

Antimicrobial Intravenous to Oral Switch Protocol


Box 1: Indications to Continue IV Therapy

  • Continuing serious sepsis (2 or more of the following) – temp > 38ºC or < 36ºC, tachycardia > 90/min, tachypnoea > 20 breaths/min, WCC > 12 or < 4 x 109/L.
  • Febrile with neutropenia (WCC <1 x 109/L).
  • Specific infections which require high dose IV therapy e.g. endocarditis, septic arthritis, osteomyelitis, meningitis, some abscesses, prosthetic device infection (consult Infectious Diseases Registrar on the acute phone via the switch board).
  • Cellulitis – if slow response consult Infectious Diseases Service as above or home IV nurse.
  • Oral route compromised e.g. vomiting, severe diarrhoea, unconscious.
  • Patient post surgery and not tolerating 1 litre of fluid orally.
  • IV antimicrobial not included in Box 2.


Box 2



amoxicillin 500 mg - 1 g tds

amoxicillin* 500 mg - 1 g tds

amoxicillin 1 g tds + metronidazole 500 mg bd + gentamicin as per renal function

amoxicillin/clavulanic acid* 500/125 mg tds

amoxicillin 1 g tds + metronidazole 500 mg bd

amoxicillin* 1 g tds + metronidazole* 600 mg bd

benzylpenicillin 1.2 g qid

phenoxymethylpenicillin 500 mg qid

clarithromycin 500 mg bd

roxithromycin* 300 mg once a day

amoxicillin/clavulanic acid 1 g/200 mg tds

amoxicillin/clavulanic acid* 500/125 mg tds

ciprofloxacin 400 mg bd

ciprofloxacin* 500 mg bd

flucloxacillin 1 g qid

flucloxacillin* 1 g qid

metronidazole 500 mg bd

metronidazole* 600 mg bd

gentamicin as per renal function

seek Infectious Diseases or Clinical Microbiology advice

* these drugs have very high oral availability

Antimicrobial Susceptibilities

Local antimicrobial susceptibility patterns (also known as “antimicrobial sensitivities” or “antibiogram”) are found here:


Probenecid has many drug interactions – check for these before prescribing
(see Clinical Pharmacology bulletin November 2022 on the Christchurch Medicines Information Service).





Tab 500 mg


500 mg with each dose of flucloxacillin 1000 mg PO three times a day.

Give both agents together and with food.



Information about this Canterbury DHB document (90640):

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Topic Code: 90640