title: The impact on health outcome measures of switching to generic medicines consequent to reference pricing: the case of olanzapine in New Zealand.
abstract: BACKGROUND
  New Zealand's Pharmaceutical Management Agency (PHARMAC) manages the list of medicines available for prescribing with government subsidy, within a fixed annual medicines budget. PHARMAC achieves this through a mix of pricing strategies including reference pricing. In 2011, PHARMAC applied generic reference pricing to olanzapine tablets.
  
  
  OBJECTIVE
  This study sought to evaluate change in outcome measures of patients switching from originator to generic olanzapine consequent to the introduction of the policy.
  
  
  METHODS
  A retrospective study using national health data collections was conducted. Outcome measures included medicines indicators (change in dosage, concomitant therapy and treatment cessation), health care service indicators (use of emergency departments, hospitals and specialist services), surveillance reports of adverse events, and mortality.
  
  
  RESULTS
  Subsequent to the removal of funding for originator brand olanzapine tablets, 99.7% of patients meeting the inclusion criteria switched to using generic olanzapine. Limited case reports of suspected therapeutic loss were received in the study time period. No increase in use of additional oral or injectable antipsychotic medication was observed after switching, nor any increase in other unique, non-antipsychotic prescription items. However, a high incidence of multiple switching between available brands was found. No net impact of switching brands on health service utilisation or mortality was found.
  
  
  CONCLUSIONS
  The study shows that a switch can be made safely from originator olanzapine to a generic brand, and suggests that switching to generics should generally be viewed more positively. Generic reference pricing achieves considerable savings and, as a pricing policy, could be applied more widely.
authors.affiliation: Health Systems Section, School of Population Health, The University of Auckland, Auckland, New Zealand. c.lessing@auckland.ac.nz.
authors.forename: Charon
authors.initials: C
authors.lastname: Lessing
authors.affiliation: Health Systems Section, School of Population Health, The University of Auckland, Auckland, New Zealand.
authors.forename: Toni
authors.initials: T
authors.lastname: Ashton
authors.affiliation: Health Systems Section, School of Population Health, and Centre of Methods and Policy Application in the Social Sciences (COMPASS), The University of Auckland, Auckland, New Zealand.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Davis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014150:Antipsychotic Agents / Q000191:economics / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000191:economics / Q000627:therapeutic use*; D017046:Cost Savings; D057915:Drug Substitution / Q000191:economics*; D016568:Drugs, Generic / Q000191:economics*; D005260:Female; D006801:Humans; D008297:Male; D008485:Medical Audit; D009520:New Zealand; D000077152:Olanzapine; D011618:Psychotic Disorders / Q000188:drug therapy*; D012189:Retrospective Studies
chemical_list: D014150:Antipsychotic Agents; D016568:Drugs, Generic; D001569:Benzodiazepines; D000077152:Olanzapine