title: Drug switching patterns among patients taking non-steroidal anti-inflammatory drugs: a retrospective cohort study of a general practitioners database in the United Kingdom.
abstract: OBJECTIVE
  To examine the frequency and determinants of switching between different non-steroidal anti-inflammatory drugs (NSAIDs) and the relationship with co-prescription of gastro-protective drugs (GPDs).
  
  
  METHODS
  This was an analysis of 30,654 patients receiving a total of 209,140 NSAID prescriptions in the UK from 1 January 1997 to 31 December 1998 identified through the MediPlus database. Analyses examined switching, repeat, termination and GPD co-prescription rates in new and continuing takers according to age and sex.
  
  
  RESULTS
  Each patient received an average of 6.8 prescriptions in the year of study. Of the prescriptions 72.2% were for one of three NSAIDs, ibuprofen, diclofenac, or naproxen, and 7.2% of prescriptions were for fixed combination products of an NSAID plus a gastroprotective drug. At least 16.0% of continuing takers, and 28.5% of new takers switched to another NSAID in the review period. On average, new patients switched more frequently than continuing patients (0.39 switches/patient/year versus 0.23 switches/patient/year, p < 0.001). Switching between NSAIDs decreased with age and was less common in women (p < 0.05). Switching was associated with a 24% and 33% increased probability of GPD prescription in new and continuing takers, respectively.
  
  
  CONCLUSIONS
  The frequency of switching, and of GPD co-prescription at switching, suggest that dissatisfaction with NSAIDs is frequent, and that gastrointestinal intolerance is a common feature of this dissatisfaction.
authors.forename: M
authors.initials: M
authors.lastname: Langman
authors.forename: K H
authors.initials: KH
authors.lastname: Kahler
authors.forename: S X
authors.initials: SX
authors.lastname: Kong
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: E
authors.initials: E
authors.lastname: Finch
authors.forename: J D
authors.initials: JD
authors.lastname: Bentkover
authors.forename: E J
authors.initials: EJ
authors.lastname: Stewart
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D003625:Data Collection; D016208:Databases, Factual; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004363:Drug Utilization; D005194:Family Practice; D005260:Female; D005765:Gastrointestinal Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D005765:Gastrointestinal Agents