title: A prescribing cascade involving cholinesterase inhibitors and anticholinergic drugs.
abstract: BACKGROUND
  The prescribing cascade model involves the misinterpretation of an adverse reaction to 1 drug and the subsequent, potentially inappropriate prescription of a second drug. We present a new example of the prescribing cascade involving cholinesterase inhibitors and anticholinergic drugs used to manage urinary incontinence.
  
  
  METHODS
  A population-based retrospective cohort study was carried out in Ontario, Canada. Participants included 44,884 older adults with dementia (20,491 were dispensed a cholinesterase inhibitor and 24,393 were not), enrolled between June 1, 1999, and March 31, 2002. Subjects were observed until they received an anticholinergic drug, stopped the cholinesterase inhibitor treatment, died, or the study period ended (March 31, 2003). The main outcome measure was receipt of an anticholinergic drug to manage urinary incontinence.
  
  
  RESULTS
  After adjusting for potential confounding factors, we observed that older adults with dementia who were dispensed cholinesterase inhibitors had an increased risk of subsequently receiving an anticholinergic drug (4.5% vs 3.1%; P<.001; adjusted hazard ratio, 1.55; 95% confidence interval, 1.39-1.72), relative to those not receiving cholinesterase inhibitors. This finding was consistent in a series of subgroup analyses.
  
  
  CONCLUSIONS
  Use of cholinesterase inhibitors is associated with an increased risk of receiving an anticholinergic drug to manage urinary incontinence. The use of an anticholinergic drug in this setting may represent a clinically important prescribing cascade. Clinicians should consider the possible contributing role of cholinesterase inhibitors in new-onset or worsening urinary incontinence and the potential risk of coprescribing cholinesterase inhibitors and anticholinergic drugs to patients with dementia.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario. gills@pccchealth.org
authors.forename: Sudeep S
authors.initials: SS
authors.lastname: Gill
authors.forename: Muhammad
authors.initials: M
authors.lastname: Mamdani
authors.forename: Gary
authors.initials: G
authors.lastname: Naglie
authors.forename: David L
authors.initials: DL
authors.lastname: Streiner
authors.forename: Susan E
authors.initials: SE
authors.lastname: Bronskill
authors.forename: Alexander
authors.initials: A
authors.lastname: Kopp
authors.forename: Kenneth I
authors.initials: KI
authors.lastname: Shulman
authors.forename: Philip E
authors.initials: PE
authors.lastname: Lee
authors.forename: Paula A
authors.initials: PA
authors.lastname: Rochon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018680:Cholinergic Antagonists / Q000627:therapeutic use*; D002800:Cholinesterase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D003704:Dementia / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008508:Medication Errors; D019338:Polypharmacy; D012189:Retrospective Studies; D014549:Urinary Incontinence / Q000188:drug therapy* / Q000209:etiology
chemical_list: D018680:Cholinergic Antagonists; D002800:Cholinesterase Inhibitors