Patient selection: children aged 1 to 5 years of age
Formulation of acetaminophen: elixir
Observations:
(1) The acetaminophen in the elixir is absorbed more rapidly than acetaminophen in tablets or capsules, with the peak concentration at 2 hours after ingestion.
(2) Children usually show a rapid clearance (short half-life) of acetaminophen.
(3) Acetaminophen only rarely causes toxicity in small children. An important risk factor is a delayed clearance of the drug, with a half-life >= 4 hours.
Recommendations:
(1) To determine serum concentrations on children who ingested more than 250 mg per kg.
(2) To make serum measurements at 1-2 hours after ingestion which should coincide with the peak concentration.
(3) Administration of enteral charcoal will only enhance elimination if it is given within an hour of the ingestion.
(4) Most children had low serum concentrations at 2 hours and could be safely discharged.
(5) A concentration at 4 hours > 200 mg/L at 4 hours may be associated with hepatotoxicity. A lower threshhold of > 150 mg/L at 4 hours may be used in adults to compensate for uncertainties in the ingestion time.
(6) Aggressive therapy with N-acetylcysteine can be instituted if there is a risk of hepatotoxicity.
where:
• On page 295 the authors mention use of 225 mg/L at 4 hours as the cutoff for possible toxicity.
