title: A 5-year follow-up study of users of benzodiazepine: starting with diazepam versus oxazepam.
abstract: BACKGROUND
  Drug dependency may develop during long-term benzodiazepine use, indicated, for example, by dose escalation. The first benzodiazepine chosen may affect the risk of dose escalation.
  
  
  OBJECTIVE
  To detect possible differences in benzodiazepine use between new users of diazepam and oxazepam over time.
  
  
  METHODS
  This 5-year prescription database study included 19 747 new benzodiazepine users, inhabitants of Norway, aged 30-60 years, with first redemption for diazepam or oxazepam.
  
  
  METHODS
  Individuals starting on diazepam versus oxazepam were analysed by logistic regression with sex, age, other drug redemptions, prescriber's specialty, household income, education level, type of work, and vocational rehabilitation support as background variables. Time to reach a daily average intake of ≥1 defined daily doses (DDD) over a 3-month period was analysed using a Cox proportional hazard regression model.
  
  
  RESULTS
  New users of oxazepam had a higher risk for dose escalation compared with new users of diazepam. This was true even when accounting for differences in sociodemographic status and previous drug use (hazard ratio [HR] 1.33, 95% confidence interval = 1.17 to 1.51).
  
  
  CONCLUSIONS
  Most doctors prescribed, according to recommendations, oxazepam to individuals they may have regarded as prone to and at risk of dependency. However, these individuals were at higher risk for dose escalation even when accounting for differences in sociodemographic status and previous drug use. Differences between the two user groups could be explained by different preferences for starting drug, DDD for oxazepam being possibly too low, and some unaccounted differences in illness.
authors.affiliation: The Norwegian Computing Center, Oslo, Norway.
authors.forename: Ingunn Fride
authors.initials: IF
authors.lastname: Tvete
authors.affiliation: Department of General Practice, Institute of Health and Society.
authors.forename: Trine
authors.initials: T
authors.lastname: Bjørner
authors.affiliation: Specialty Clinical Pharmacology, Department of Pharmacology, University of Oslo, Oslo, Norway.
authors.forename: Tor
authors.initials: T
authors.lastname: Skomedal
mesh_terms: D000328:Adult; D014151:Anti-Anxiety Agents / Q000627:therapeutic use*; D001007:Anxiety / Q000188:drug therapy* / Q000453:epidemiology; D003863:Depression / Q000188:drug therapy* / Q000453:epidemiology; D003975:Diazepam / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D010076:Oxazepam / Q000627:therapeutic use*; D063487:Prescription Drug Misuse / Q000706:statistics & numerical data*; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology
chemical_list: D014151:Anti-Anxiety Agents; D010076:Oxazepam; D003975:Diazepam
keywords: Cox models; anxiety; benzodiazepines; diazepam; general practice; logistic models; oxazepam