title: Fixed-dose combination and single active ingredient drugs: a comparative cost analysis.
abstract: BACKGROUND
  Fixed-dose combination (FDC) drugs are formulations of two or more active ingredients.
  
  
  OBJECTIVE
  To assess the pricing structure and price difference of all US FDA-approved FDCs and single drugs included in the combination.
  
  
  METHODS
  Data were collected from the FDA Orange Book and Drugs@FDA. Average Wholesale Price (AWP) unit price data were derived from The Red Book.
  
  
  RESULTS
  The FDA approved 117 FDC. The average AWP difference percentage between the FDC and the sum of the single drugs in the FDC is 84.9 ± 26.2%, and varied by therapeutic class (p < 0.001). The FDC AWP averaged 83.3 ± 23.4% of the single drug AWP sum when there are no generics, and 95.1 ± 42.3% (p < 0.01) when there are two generic single active ingredients in the FDC.
  
  
  CONCLUSIONS
  The price difference between FDC and single active ingredients in the combination is correlated with the therapeutic class, the year of FDC approval, and the number of single ingredients in the combination that have generics.
authors.affiliation: a 1 School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Hao
authors.affiliation: a 1 School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA.
authors.forename: Rosa
authors.initials: R
authors.lastname: Rodriguez-Monguio
authors.affiliation: b 2 Massachusetts College of Pharmacy and Health Sciences, Boston, MA, USA.|c 3 Brigham and Women's Hospital, Division of General Medicine and Primary Care, Boston, MA, USA.
authors.forename: Enrique
authors.initials: E
authors.lastname: Seoane-Vazquez
mesh_terms: D017277:Drug Approval; D004338:Drug Combinations; D016527:Drug Costs / Q000145:classification; D004359:Drug Therapy, Combination; D016568:Drugs, Generic / Q000008:administration & dosage / Q000191:economics*; D006801:Humans; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000191:economics*; D014481:United States
chemical_list: D004338:Drug Combinations; D016568:Drugs, Generic; D004364:Pharmaceutical Preparations
keywords: Food and Drug Administration; average wholesale price; drug approvals; fixed-dose combination drugs