title: Delayed toxic acetaminophen level after initial four hour nontoxic level.
abstract: Antidotal therapy for acetaminophen poisoning is routinely based on a single acetaminophen level obtained four or more hours after ingestion. Some experts recommend additional acetaminophen levels if there are coingestants. This case report describes a 20-year-old woman who ingested acetaminophen 13 g, propoxyphene napsylate 2 g and naproxen sodium 3.75 g. A 4.5 h acetaminophen level was 83.5 mg/L (nontoxic). A 6.75 h acetaminophen level was 124.6 mg/L (toxic). The patient was treated with N-acetylcysteine and recovered without sequelae. This is the first published report of a delayed toxic acetaminophen level occurring after an initial nontoxic level. Although rare, the possibility of a delayed peak acetaminophen level merits consideration, particularly with coingestions that delay gastric emptying.
authors.affiliation: Valley Medical Center, University of California, San Francisco, School of Medicine, Department of Emergency Medicine, Fresno 93702.
authors.forename: T V
authors.initials: TV
authors.lastname: Tighe
authors.forename: F G
authors.initials: FG
authors.lastname: Walter
mesh_terms: D000082:Acetaminophen / Q000097:blood* / Q000506:poisoning*; D000111:Acetylcysteine / Q000627:therapeutic use; D000328:Adult; D011431:Dextropropoxyphene / Q000506:poisoning; D062787:Drug Overdose / Q000097:blood / Q000628:therapy; D005260:Female; D006801:Humans; D009288:Naproxen / Q000506:poisoning; D013997:Time Factors
chemical_list: D000082:Acetaminophen; D009288:Naproxen; D011431:Dextropropoxyphene; D000111:Acetylcysteine