Canterbury DHB


September 2016

Central Nervous System


  • zopiclone – added a note about a usual starting dose of 3.75 mg
  • flumazenil (benzodiazepine antagonist) – added a dose
  • clonazepam – added a minimum dosing interval

Antipsychotic Drugs

  • long acting/modified release injections are available for some antipsychotics and must not be confused with the other injectable forms – added a note
  • haloperidol – added a QT prolongation note
  • clozapine – added a note about prescribing a regular laxative and a note about TDM

Antidepressant drugs

  • fluoxetine – changed upper dose in range from 80 mg to 60 mg/day
  • venlafaxine – changed upper dose in range from 150 mg to 225 mg/day
  • mirtazapine – removed PHARMAC restriction comment as no longer restricted.

Central Nervous System Stimulants

  • methylphenidate – added trade names to minimise confusion


  • lacosamide – added
  • levetiracetam – increased upper limit of iv dose

Dopaminergic Drugs used in Parkinsonism

  • different formulations of levodopa combinations have different durations of action – added a note
  • levodopa combinations – changed dose information to initial doses
  • lisuride – removed as delisted by PHARMAC

Drugs used in Neuromuscular Disorders

  • pyridostigmine – added an upper dose comment
  • dantrolene – added a malignant hyperthermia iv dose



  • cefotaxime – deleted
  • cefepime – deleted

Other Beta-lactams – carbapenems

  • imipenem + cilastatin – deleted
  • ertapenem – added

Other antimicrobials

  • fusidate sodium – deleted
  • nitrofurantoin – adjusted the use in renal dysfunction comment
  • rifampicin – added
  • vancomycin – changed lower dose in dose range


  • norfloxacin – deleted

Antifungal Drugs

  • amphotericin B (liposomal) – deleted
  • itraconazole – adjusted the absorption comment

Antiviral Drugs

  • Some antivirals sound very similar – added a note
  • valaciclovir – added
  • Hepatitis treatment – added note for hepatitis B and to consult about Hepatitis C drugs

Endocrine System

  • warfarin – clarified different brands and added an alert


  • Mixed insulins – added note about mixed insulins not being equivalent

Thyroid and Antithyroid Drugs

  • levothyroxine – removed the note about different brands not being interchangeable

Male Sex Hormones and Antagonists

  • cyproterone – increased upper dose in range

Drugs affecting Bone Metabolism

  • zoledronic acid – added clarification around indication for each formulation

Pharmacology Guidelines

Routes of Administration

  • Intravenous (IV) – added clarification around single vs. multiple lumens

Drug-Food Interactions

  • reviewed

Therapeutic Drug Monitoring (TDM)

  • Table – added all included in TDM profiles

Drug-Drug Interactions

  • Drugs commonly involved in interactions – removed

Drug Metabolism and Transport

  • CYP enzymes – throughout re-organised substrates, split inhibitors into strong and moderate (with definitions) and included only significant inducers (with definition)
  • transporters – added comment about the effect of inhibitors and inducers

Information about this Canterbury DHB document (308672):

Document Owner:

Not assigned (see Who's Who)

Last Updated:

Next Review Due:


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

Topic Code: 308672