title: Pharmaceutical brand substitution in Australia--are there multiple switches per prescription?
abstract: BACKGROUND
  In Australia, brand substitution by pharmacists has been possible since 1994. There is no limit to the number of substitutions per prescription. Doctors have expressed concern that patients may receive a different product each time their prescription repeats are dispensed, which has the potential to confuse patients. It is unknown how often multiple substitutions per prescription occur.
  
  
  OBJECTIVE
  We aimed to identify the number of switches per prescription for a range of medicines and to determine the number of different brand and generic products supplied on each prescription.
  
  
  METHODS
  Repatriation Pharmaceutical Benefits Scheme prescription claims between 1 January 2001 and 28 February 2006 were identified for atenolol, citalopram, enalapril, metformin, omeprazole, ramipril, and simvastatin. Original prescriptions with five repeats and all supplies dispensed were included. Switches were identified if a different product was supplied on consecutive repeat dispensings.
  
  
  RESULTS
  533,279 original prescriptions were included. 488,735 (92%) had no switches on repeats and 37,513 (7%) had only one switch. Only 1% of all prescriptions had more than one switch identified on repeats, and in most cases only two different products were supplied. None of the prescriptions had a different product supplied on each dispensing.
  
  
  CONCLUSIONS
  Multiple switches per prescription are uncommon and multiple different products are rarely supplied on repeats of the same prescription. The rules of the brand substitution policy appear to be adequate in allowing brand choice for patients, without leading to multiple switches per prescription.
authors.affiliation: Quality Use of Medicines and Pharmacy Research Centre, Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia. lisa.kalisch@postgrads.unisa.edu.au
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Kalisch
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Roughead
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Gilbert
mesh_terms: D016568:Drugs, Generic / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D007345:Insurance Claim Review; D013021:South Australia; D013810:Therapeutic Equivalency
chemical_list: D016568:Drugs, Generic