title: Selegiline shortage: Causes and costs of a generic drug shortage.
abstract: BACKGROUND
  In September 2007, shortages of generic selegiline occurred, forcing patients to either switch to more expensive alternatives or forego treatment. We sought to evaluate prescription trends of generic selegiline and to quantify the economic impact of any resulting drug substitution of more expensive alternatives.
  
  
  METHODS
  We analyzed proprietary data from IMS Health on monthly prescriptions in the United States for selegiline and potential substitutes from February 2002 through December 2007. Linear regression was used to predict the number of expected prescriptions after August 2007 had a shortage not occurred. The main outcome measures were the changes in prescriptions filled and the economic impact of drug substitution.
  
  
  RESULTS
  Prior to the shortage, total prescriptions filled for generic selegiline decreased 42%, and supply consolidated into one company, Apotex Inc., Toronto, Canada, whose market share increased from 41% to 83%. During the first 4 months of the shortage, Apotex Inc. filled 10,500 fewer prescriptions than projected and other selegiline manufacturers filled 7,400 more than projected for a net shortage of 3,100 prescriptions. The number of branded selegiline capsules filled during this period increased by 1,800 above projections, and 1,300 prescriptions for generic selegiline were not refilled or substituted. The societal cost of substituting generic selegiline with branded capsules was $75,000 over the first 4 months of the shortage.
  
  
  CONCLUSIONS
  Generic drug shortages carry economic and health implications. Given ongoing consolidation in the generics drug industry, these shortages may become more common and may require heightened regulatory scrutiny of the generic drug industry.
authors.affiliation: Department of Neurology, University at Buffalo, NY, USA. ray.dorsey@ctcc.rochester.edu
authors.forename: E R
authors.initials: ER
authors.lastname: Dorsey
authors.forename: J P
authors.initials: JP
authors.lastname: Thompson
authors.forename: E J
authors.initials: EJ
authors.lastname: Dayoub
authors.forename: B
authors.initials: B
authors.lastname: George
authors.forename: L A
authors.initials: LA
authors.lastname: Saubermann
authors.forename: R G
authors.initials: RG
authors.lastname: Holloway
mesh_terms: D000978:Antiparkinson Agents / Q000191:economics / Q000627:therapeutic use*; D016527:Drug Costs / Q000706:statistics & numerical data* / Q000639:trends; D004345:Drug Industry / Q000191:economics / Q000331:legislation & jurisprudence / Q000592:standards; D004335:Drug and Narcotic Control / Q000706:statistics & numerical data / Q000639:trends; D016568:Drugs, Generic / Q000191:economics / Q000627:therapeutic use*; D006297:Health Services Accessibility / Q000706:statistics & numerical data* / Q000639:trends; D006801:Humans; D010300:Parkinson Disease / Q000188:drug therapy*; D055656:Prescriptions / Q000191:economics / Q000706:statistics & numerical data; D012642:Selegiline / Q000191:economics / Q000627:therapeutic use*
chemical_list: D000978:Antiparkinson Agents; D016568:Drugs, Generic; D012642:Selegiline