title: Patterns of acetaminophen medication use associated with exceeding the recommended maximum daily dose.
abstract: BACKGROUND
  Acetaminophen overuse has been linked to liver injury.
  
  
  OBJECTIVE
  To identify patterns of medication use associated with exceeding the recommended daily maximum dose of 4 g acetaminophen.
  
  
  METHODS
  Respondents from a national panel completed a detailed daily medication diary online for 7 days (n = 5649), identifying medications taken from a comprehensive list of over-the-counter (OTC) and prescription (Rx) acetaminophen medications. Respondents were not told the study concerned acetaminophen. Total daily intake was calculated from diary data. Generalized estimating equations assessed the association of medication patterns with exceeding 4 g per day among 3618 respondents who used acetaminophen medications (on 13,852 days) during the diary period.
  
  
  RESULTS
  Acetaminophen intake exceeded 4 g on 3.1% of usage days; median intake on those days was 5.5 g. As expected, days when intake exceeded 4 g were almost always (92%) marked by deviations from label directions-exceeding the one-time dose, re-dosing too soon, and concomitant use of multiple acetaminophen medications. Re-dosing too soon was the most frequent deviation, and concomitant use was most strongly tied to exceeding the daily limit. Use of both an Rx and an OTC medication on the same day also increased the odds of exceeding 4 g on days when concomitant use occurred.
  
  
  CONCLUSIONS
  Excess dosing of acetaminophen is associated with deviations from label directions and by use of both OTC and Rx medications containing acetaminophen within a single concomitant use day.
authors.affiliation: Pinney Associates, Pittsburgh, PA, USA.|Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Saul
authors.initials: S
authors.lastname: Shiffman
authors.affiliation: Pinney Associates, Pittsburgh, PA, USA.|School of Nursing, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Rohay
authors.affiliation: Pinney Associates, Pittsburgh, PA, USA.
authors.forename: Deena
authors.initials: D
authors.lastname: Battista
authors.affiliation: Slone Epidemiology Center at Boston University, Boston, MA, USA.
authors.forename: Judith P
authors.initials: JP
authors.lastname: Kelly
authors.affiliation: Appleseed Consumer Insight, Arlington, MA, USA.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Malone
authors.affiliation: Janssen Research & Development, LLC, Titusville, NJ, USA.
authors.forename: Rachel B
authors.initials: RB
authors.lastname: Weinstein
authors.affiliation: Slone Epidemiology Center at Boston University, Boston, MA, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Kaufman
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage*; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D020407:Internet; D008297:Male; D004366:Nonprescription Drugs / Q000008:administration & dosage*; D011795:Surveys and Questionnaires
chemical_list: D018712:Analgesics, Non-Narcotic; D004366:Nonprescription Drugs; D000082:Acetaminophen
keywords: acetaminophen; dosing behavior; drug safety; epidemiology; pharmacoepidemiology; survey research