title: Consumer usage patterns of nonprescription histamine2-receptor antagonists.
abstract: OBJECTIVE
  Prescription to over-the-counter (OTC) drug switches are increasingly common. Yet little is known about how the public uses these reclassified products. Histamine2-receptor antagonists (H2RAs) are popular examples, although they may be supplanted by OTC proton pump inhibitors (PPIs). We examined the extent to which consumers substitute OTC H2RAs for physician care and/or engage in off-label use of these medications.
  
  
  METHODS
  Self-administered anonymous survey of 1,116 adult OTC H2RA consumers in a random sample of 20 Los Angeles pharmacies from a major retail chain. Off-label use was defined by FDA warning label (e.g., bloody stools, dysphagia). Substitution was defined by intent to use H2RA instead of going to a physician.
  
  
  RESULTS
  Forty-six percent engaged in off-label use of OTC H2RAs. Off-label use was independently associated with lower income, substitution for physician care, prior gastrointestinal disease, and past prescription H2RA use. Thirty-four percent substituted OTC H2RA use for physician care, and 54% of these met the criteria for off-label use. Substitution was associated with lack of health insurance, lack of time to see a physician, the belief that OTC H2RA was cheaper than clinic visits, and nonwhite race.
  
  
  CONCLUSIONS
  Almost one-half of adult consumers reported using OTC H2RAs in a manner inconsistent with FDA labeling, and this off-label use was associated with substitution for physician care. Traditionally vulnerable populations were more prone to off-label use and to substituting H2RAs for physician care. Further studies are needed to assess patient outcomes, identify remedies, and explore implications for the reclassification of PPIs.
authors.affiliation: Department of Family and Preventive Medicine, UC San Diego, La Jolla, California 92093, USA.
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Shi
authors.forename: Ian M
authors.initials: IM
authors.lastname: Gralnek
authors.forename: Gareth S
authors.initials: GS
authors.lastname: Dulai
authors.forename: Ali
authors.initials: A
authors.lastname: Towfigh
authors.forename: Steven
authors.initials: S
authors.lastname: Asch
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006635:Histamine H2 Antagonists / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D004366:Nonprescription Drugs / Q000627:therapeutic use*; D012651:Self Medication / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires
chemical_list: D006635:Histamine H2 Antagonists; D004366:Nonprescription Drugs