title: Acetaminophen (paracetamol) oral absorption and clinical influences.
abstract: Acetaminophen (paracetamol) is a widely used nonopioid, non-NSAID analgesic that is effective against a variety of pain types, but the consequences of overdose can be severe. Because acetaminophen is so widely available as a single agent and is increasingly being formulated in fixed-ratio combination analgesic products for the potential additive or synergistic analgesic effect and/or reduced adverse effects, accidental cumulative overdose is an emergent concern. This has rekindled interest in the sites, processes, and pharmacokinetics of acetaminophen oral absorption and the clinical factors that can influence these. The absorption of oral acetaminophen occurs primarily along the small intestine by passive diffusion. Therefore, the rate-limiting step is the rate of gastric emptying into the intestines. Several clinical factors can affect absorption per se or the rate of gastric emptying, such as diet, concomitant medication, surgery, pregnancy, and others. Although acetaminophen does not have the abuse potential of opioids or the gastrointestinal bleeding or organ adverse effects of NSAIDs, excess amounts can produce serious hepatic injury. Thus, an understanding of the sites and features of acetaminophen absorption--and how they might be influenced by factors encountered in clinical practice--is important for pain management using this agent. It can also provide insight for design of formulations that would be less susceptible to clinical variables.
authors.affiliation: Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania, U.S.A.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Raffa
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A.|Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, U.S.A.|Department of Anesthesiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A.
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Pergolizzi
authors.affiliation: NEMA Research Inc., Naples, Florida, U.S.A.
authors.forename: Robert
authors.initials: R
authors.lastname: Taylor
authors.affiliation: Mallinckrodt (Covidien), Hazelwood, Missouri, U.S.A.
authors.forename: John F
authors.initials: JF
authors.lastname: Decker
authors.affiliation: Mallinckrodt (Covidien), Hazelwood, Missouri, U.S.A.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Patrick
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage* / Q000378:metabolism; D000284:Administration, Oral; D000700:Analgesics / Q000008:administration & dosage / Q000378:metabolism; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage* / Q000378:metabolism; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000378:metabolism; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000378:metabolism; D062787:Drug Overdose; D065569:Gastrointestinal Absorption / Q000187:drug effects* / Q000502:physiology; D006801:Humans
chemical_list: D000700:Analgesics; D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000082:Acetaminophen
keywords: absorption; acetaminophen; gastric emptying; paracetamol; review