title: Comparative adherence to oxybutynin or tolterodine among older patients.
abstract: OBJECTIVE
  To compare persistence of oxybutynin or tolterodine therapy among older patients newly prescribed one of these drugs.
  
  
  METHODS
  We conducted a retrospective cohort study of Ontarians aged 66 years and older who were newly prescribed either drug between January 1, 2000 and December 31, 2007. Persistence with treatment was defined on the basis of refills for the drug within a grace period equal to 50% of the prescription duration.
  
  
  RESULTS
  We identified 31,996 patients newly treated with oxybutynin and 24,855 newly treated with tolterodine. After 2 years of follow-up, persistence on oxybutynin (9.4%) was significantly lower than that on tolterodine (13.6%, p < 0.0001). The median time to discontinuation of oxybutynin and tolterodine was 68 and 128 days, respectively.
  
  
  CONCLUSIONS
  Our findings suggest that the tolerability of these drugs differs substantially.
authors.affiliation: The Institute for Clinical Evaluative Sciences, Toronto, ON, Canada. tara.gomes@ices.on.ca
authors.forename: Tara
authors.initials: T
authors.lastname: Gomes
authors.forename: David N
authors.initials: DN
authors.lastname: Juurlink
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Mamdani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001559:Benzhydryl Compounds / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D003408:Cresols / Q000009:adverse effects / Q000627:therapeutic use*; D016208:Databases, Factual; D011307:Drug Prescriptions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008333:Mandelic Acids / Q000009:adverse effects / Q000627:therapeutic use*; D055118:Medication Adherence; D018727:Muscarinic Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D009313:National Health Programs; D009864:Ontario; D010665:Phenylpropanolamine / Q000009:adverse effects / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D000068737:Tolterodine Tartrate; D053202:Urinary Incontinence, Urge / Q000188:drug therapy*
chemical_list: D001559:Benzhydryl Compounds; D003408:Cresols; D008333:Mandelic Acids; D018727:Muscarinic Antagonists; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate; C005419:oxybutynin