Fatalities involving acetaminophen combination products reported to United States poison centers

Context. Deaths from overdose of acetaminophen (APAP) combination medications are reported, yet the individual ingredients are not well examined as individual putative causes of death. Objective. To examine the individual contribution of APAP or other ingredient(s) to fatalities resulting from ingestion of APAP combination products reported to poison centers. Materials and methods. A search in the United States (US) National Poison Data System between 1 January 2000 and 31 December 2009 (10 years) was conducted. Only fatal cases determined by American Association of Poison Control Centers Fatality Review team to be caused by ingestion of one or more APAP combination products were included. The fatality abstract narrative for each case was obtained. Each narrative abstract was rated independently by four reviewers and putative cause of death was determined to be APAP, 'other ingredient' or 'unable to determine'. Fleiss' Kappa test was utilized to assess interrater agreement. Results. Three hundred and thirty-seven deaths met inclusion criteria: 204 were due to suicides, 96 were the result of nonmedical use, 3 were from a therapeutic error, 1 resulted from an unsupervised pediatric ingestion, and 33 were due to unknown reason for exposure. The overall putative cause of death was APAP in 60.8%, other ingredients in 29.7%, and unable to determine in 9.5% of fatalities. APAP was responsible for the fatality in 79.2% of deaths resulting from nonmedical use of APAP combination products. Fleiss Kappa was 0.74, indicating substantial interrater agreement. Discussion and conclusion. The most common putative cause of death in fatal overdoses involving APAP combination products reported to US poison centers is the APAP component.