Overdose of extended-release acetaminophen.

To the Editor: A previously healthy 13-year-old girl arrived at the hospital 19 hours after ingesting two handfuls of Tylenol Extended Relief (McNeil Pharmaceuticals), a new extended-release formulation of acetaminophen containing 650 mg per caplet. Vomiting and abdominal pain began six hours after ingestion. Examination revealed tenderness of the epigastrium and right upper quadrant. The serum acetaminophen level was 89 μg per milliliter, with an alanine aminotransferase level of 180 IU per liter, a bilirubin level of 1.7 mg per deciliter, and an international normalized ratio of body weight of 1.5. The patient received an initial oral dose of 140 . . .