Canterbury DHB


October 2020

Pink Book General Advice and Introduction

Prescribing Instructions for Medicines

  • A new section has been added to these instructions titled Use of Medicines Outside PHARMAC Hospital Medicines List (HML) Restrictions. The content describes the CDHB process for Named Patient Pharmaceutical Assessment (NPPA) applications.

Prescribing Guidelines

Thiopurine Dosing Guideline in Immunosuppressive Therapy

  • New title (previously titled Azathioprine/6-mercaptopurine Dosing Guideline in Immunosuppressive Therapy)
  • Added definitions for TMPT, 6TGM and 6MMP.
  • Added: TPMT polymorphisms result in large differences in 6-TGN and 6-MMP concentrations, so it is important to measure TPMT enzyme activity (i.e. phenotype) before initiating thiopurine therapy.
  • Added detail about addition of allopurinol to thiopurines: only with a dose reduction of the thiopurine to one-third (e.g. 150 mg down to 50 mg).

Pharmacokinetic Table


  • Reviewed


  • Added


  • Deleted

Bioavailability Column

  • This column has been amended, removing the annotation for giving the medicine either with or without food.
  • Going forward, instructions regarding food will be provided only where considered clinically important.



Information about this Canterbury DHB document (808050):

Document Owner:

Not assigned (see Who's Who)

Last Updated:

October 2020

Next Review Due:


Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document.

Topic Code: 808050