Comparison of Outcomes Following a Switch From a Brand to an Authorized Versus Independent Generic Drug

Clin Pharmacol Ther. 2018 Feb;103(2):310-317. doi: 10.1002/cpt.591. Epub 2017 Oct 10.


Authorized generics are identical in formulation to brand drugs, manufactured by the brand company but marketed as a generic. Generics, marketed by generic manufacturers, are required to demonstrate pharmaceutical and bioequivalence to the brand drug, but repetition of clinical trials is not required. This retrospective cohort study compared outcomes for generics and authorized generics, which serves as a generic vs. brand proxy that minimizes bias against generics. For the seven drugs studied between 1999 and 2014, 5,234 unique patients were on brand drugs prior to generic entry and 4,900 (93.6%) switched to a generic. During the 12 months following the brand-to-generic switch, patients using generics vs. authorized generics were similar in terms of outpatient visits, urgent care visits, hospitalizations, and medication discontinuation. The likelihood of emergency department (ED) visits was slightly higher for authorized generics compared with generics. These data suggest that generics were clinically no worse than their proxy brand comparators.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Administrative Claims, Healthcare
  • Adult
  • Aged
  • Ambulatory Care
  • Data Mining / methods
  • Drug Substitution* / adverse effects
  • Drug-Related Side Effects and Adverse Reactions / diagnosis
  • Drug-Related Side Effects and Adverse Reactions / etiology*
  • Drug-Related Side Effects and Adverse Reactions / therapy
  • Drugs, Generic / adverse effects
  • Drugs, Generic / therapeutic use*
  • Electronic Health Records
  • Emergency Service, Hospital
  • Evidence-Based Medicine / methods
  • Female
  • Hospitalization
  • Humans
  • Male
  • Middle Aged
  • Patient Safety
  • Product Surveillance, Postmarketing
  • Retrospective Studies
  • Risk Assessment
  • Risk Factors
  • Time Factors


  • Drugs, Generic