title: Pharmacy study of natural health product adverse reactions (SONAR): a cross-sectional study using active surveillance in community pharmacies to detect adverse events associated with natural health products and assess causality.
abstract: OBJECTIVE
  To investigate the rates and causality of adverse event(s) (AE) associated with natural health product (NHP) use, prescription drug use and concurrent NHP-drug use through active surveillance in community pharmacies.
  
  
  METHODS
  Cross-sectional study of screened patients.
  
  
  METHODS
  10 community pharmacies across Alberta and British Columbia, Canada from 14 January to 30 July 2011.
  
  
  METHODS
  The participating pharmacy staff screened consecutive patients, or agents of patients, who were dropping or picking up prescription medications.
  
  
  METHODS
  Patients were screened to determine the proportions of them using prescription drugs and/or NHPs, as well as their respective AE rates. All AEs reported by the screened patients who took a NHP, consented to, and were available for, a detailed telephone interview (14%) were adjudicated fully to assess for causality.
  
  
  RESULTS
  Over a total of 105 pharmacy weeks and 1118 patients screened, 410 patients reported taking prescription drugs only (36.7%; 95% CI 33.9% to 39.5%), 37 reported taking NHPs only (3.3%; 95% CI 2.4% to 4.5%) and 657 reported taking prescription drugs and NHPs concurrently (58.8%; 95% CI 55.9% to 61.6%). In total, 54 patients reported an AE, representing 1.2% (95% CI 0.51% to 2.9%), 2.7% (95% CI 0.4% to 16.9%) and 7.3% (95% CI 5.6% to 9.6%) of each population, respectively. Compared with patients who reported using prescription drugs, the patients who reported using prescription drugs and NHPs concurrently were 6.4 times more likely to experience an AE (OR; 95% CI 2.52 to 16.17; p<0.001). Combined with data from Ontario, Canada, a national proportion was calculated, which found that 45.4% (95% CI 43.8% to 47.0%) of Canadians who visit community pharmacies take NHPs and prescription drugs concurrently, and of those, 7.4% (95% CI 6.3% to 8.8%) report an AE.
  
  
  CONCLUSIONS
  A substantial proportion of community pharmacy patients use prescription drugs and NHPs concurrently; these patients are at a greater risk of experiencing an AE. Active surveillance provides a means of detecting such AEs and collecting high-quality data on which causality assessment can be based.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Candace
authors.initials: C
authors.lastname: Necyk
authors.forename: Ross T
authors.initials: RT
authors.lastname: Tsuyuki
authors.forename: Heather
authors.initials: H
authors.lastname: Boon
authors.forename: Brian C
authors.initials: BC
authors.lastname: Foster
authors.forename: Don
authors.initials: D
authors.lastname: Legatt
authors.forename: George
authors.initials: G
authors.lastname: Cembrowski
authors.forename: Mano
authors.initials: M
authors.lastname: Murty
authors.forename: Joanne
authors.initials: J
authors.lastname: Barnes
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Charrois
authors.forename: John T
authors.initials: JT
authors.lastname: Arnason
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ware
authors.forename: Rhonda J
authors.initials: RJ
authors.lastname: Rosychuk
authors.forename: Sunita
authors.initials: S
authors.lastname: Vohra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001688:Biological Products / Q000009:adverse effects* / Q000627:therapeutic use; D001955:British Columbia; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D010594:Pharmacies; D010595:Pharmacists; D055553:Prescription Drugs / Q000009:adverse effects* / Q000627:therapeutic use; D012111:Residence Characteristics; D011795:Surveys and Questionnaires
chemical_list: D001688:Biological Products; D055553:Prescription Drugs
keywords: Complementary Medicine; Toxicology