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While the total incidence of adverse drug events (ADEs) caused by high-risk medicines in NZ is unknown, recently published trigger tool data found that opioids (32.9 percent) and anticoagulants (10 percent) were most commonly implicated for causing an ADE. Of the 19 ADEs identified in the study as contributing to severe harm or death, 50 percent were related to opioids and anticoagulant use.[1] These results align with international literature.

60 percent of adverse drug events are thought to be preventable.In New Zealand, between July 2007 and June 2013 there were 2159 reported serious adverse events. 132 were medication-related events. Of these 23 related to opioids, 19 related to anticoagulants and seven related to insulin.[3] This is only the tip of the iceberg as not all medication-related events are recognised or reported.

Factors that increase high-risk medicines’ potential for harm include:


  • having a narrow therapeutic index – too little or too much has the potential to cause harm
  • complex or unusual dosing – for example, weekly rather than daily
  • high monitoring requirements
  • significant interactions with other medicines, herbal products and food
  • availability in multiple strengths and forms
  • look-alike sound-alike naming and packaging.

See the publications and resources section for the high-risk medicines infographic, high-risk medicines factsheet and the frequently asked questions for more information on the case for change.


  1. Seddon, ME, Jackson A, Cameron C et al. The Adverse Drug Event Collaborative: a joint venture to measure medication-related patient harm. NZMJ 25 January 2013, Vol 126.
  2. Bates DW, Cullen DJ, Laird N et al. Incidence of adverse drug events and potential adverse drug events: implications for prevention. JAMA 1995; 274:29–34. 
  3. Health Quality & Safety Commission Reportable Events