title: Polypharmacy, adverse drug-related events, and potential adverse drug interactions in elderly patients presenting to an emergency department.
abstract: OBJECTIVE
  We sought to document the degree of polypharmacy, the frequency of adverse drug-related events (ADREs) leading to emergency department presentation that were recognized by emergency physicians, and the frequency of potential adverse drug interactions (PADIs) in medication regimens of elderly patients in the ED.
  
  
  METHODS
  We conducted a retrospective chart review on 300 randomly selected ED visits made by patients 65 years of age and older between January 1 and December 31, 1998. ADREs were defined according to a standardized algorithm. PADIs were identified by using the drug interaction database PharmVigilance.
  
  
  RESULTS
  After excluding 17 patient visits with inadequate documentation, 283 were left for review. Of these, 257 (90.8%) patients were taking 1 or more medications (prescribed or over the counter). The number of medications consumed ranged from 0 to 17 and averaged 4.2 (SD+/-3.1) drugs per patient. ADREs accounted for 10.6% of all ED visits in our patient group. The most frequently implicated classes of medications were nonsteroidal anti-inflammatory drugs, antibiotics, anticoagulants, diuretics, hypoglycemics, beta-blockers, calcium-channel blockers, and chemotherapeutic agents. Thirty-one percent of all patients in our group had at least 1 PADI in their medication list. Among patients who presented because of an ADRE, 50% had at least 1 PADI in their medication list that was unrelated to the ADRE with which they presented.
  
  
  CONCLUSIONS
  ADREs are an important cause of ED presentation in the elderly. PADIs are found in a significant proportion of medication lists. Emergency physicians must be vigilant in monitoring elderly patients for medication-related problems.
authors.affiliation: McGill University Royal College Emergency Medicine Residency Training Program, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada. chohl@hotmail.com
authors.forename: C M
authors.initials: CM
authors.lastname: Hohl
authors.forename: J
authors.initials: J
authors.lastname: Dankoff
authors.forename: A
authors.initials: A
authors.lastname: Colacone
authors.forename: M
authors.initials: M
authors.lastname: Afilalo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006769:Hospitals, General; D006801:Humans; D008297:Male; D011792:Quebec; D012189:Retrospective Studies