Estimated risk of hepatotoxicity after an acute acetaminophen overdose in alcoholics

Patterns of acetaminophen toxicity among patients with low-risk serum concentrations

OBJECTIVE

In 2012, the Commission on Human Medicines mandated lowering the acetaminophen toxicity nomogram treatment threshold in the UK to 100 µg/ml at 4 h post-ingestion. The present study aim was to evaluate biochemical and liver toxicity patterns in patients who presented with acetaminophen overdose and had low serum acetaminophen concentrations (<150 µg/ml).

METHODS

Patients admitted to the emergency department with a clear history of acute acetaminophen overdose with or without other medication or ethanol were consecutively enrolled into this retrospective cohort study. Patients with serum acetaminophen concentration >150 µg/ml or an unknown ingestion time were excluded. Data were extracted from electronic medical records and are presented as mean ± SD or median (interquartile range).

RESULTS

A total of 103 patients were included (median age, 17 [4-21] years) and 80 (78%) were female. The median ingested acetaminophen dose was 5000 (2850-7650) mg. At baseline, the median serum acetaminophen concentration was 42 (4.5-64.8) µg/ml, and median alanine aminotransferase and aspartate aminotransferase levels were 22 (17-28) and 27 (16-45) IU/L, respectively. Twenty patients were treated with acetylcysteine, with none developing adverse reactions. No patient developed hepatotoxicity, including patients with initial multiple product ingestion or other risk factors.

CONCLUSIONS

Patients presenting with an acute acetaminophen overdose with acetaminophen level <150 µg/ml, including patients with other risk factors, are at low risk of hepatotoxicity.

Drug-induced liver injury: what was new in 2008?

BACKGROUND

Given the number of publications appearing annually regarding drug-induced liver injury (DILI), there remains a need to concisely summarize each year's new crop of case series and reports as well as the advances in mechanisms of liver injury and in the field of pharmacogenomics relating to DILI.

OBJECTIVE

To present an up-to-date review of the past year's most important clinical studies and reports of DILI, placing them into context of previous publications.

METHODS

A Medline search was conducted of all manuscripts appearing in the fields "hepatotoxicity" and "drug-induced liver injury" during the calendar year 2008. The most clinically relevant English language case reports and studies exploring mechanisms and risk factors for DILI were then chosen for review, and supplemented with older literature where appropriate.

CONCLUSIONS

As in past years, 2008 was replete with publications dealing with virtually all facets of DILI, including updated incidence and prevalence data, as well as the latest information regarding mechanisms of liver injury. Data from the first 300 patients in the National Institute of Health-sponsored DILI Network registry of > 100 non-acetaminophen causes were presented. Antimicrobials and CNS drugs were responsible for > 60% of cases, with herbals and dietary supplements being increasingly reported. Identification of genetic predispositions to DILI is coming of age with the FDA calling for the testing of human leukocyte antigen B(*)5701 before the use of abacavir to reduce the risk of hypersensitivity reactions. Several groups emphasized the pitfalls in utilizing Roussel Uclaf Causality Assessment Method and other causality assessment methodologies, and an updated review appeared on the use of potentially hepatotoxic medications in patients with underlying liver disease.

Acetaminophen-associated hepatic injury: evaluation of acetaminophen protein adducts in children and adolescents with acetaminophen overdose

Acetaminophen protein adducts (APAP adducts) were quantified in 157 adolescents and children presenting at eight pediatric hospitals with the chief complaint of APAP overdose. Two of the patients required liver transplantation, whereas all the others recovered spontaneously. Peak APAP adducts correlated with peak hepatic transaminase values, time-to-treatment with N-acetylcysteine (NAC), and risk determination per the Rumack-Matthews nomogram. A population pharmacokinetic analysis (NONMEM) was performed with post hoc empiric Bayesian estimates determined for the elimination rate constants (k(e)), elimination half-lives (t(1/2)), and maximum concentration of adducts (C(max)) of the subjects. The mean (+/-SD)k(e) and half-life were 0.486 +/- 0.084 days(-1) and 1.47+/- 0.30 days, respectively, and the C(max) was 1.2 (+/-2.92) nmol/ml serum. The model-derived, predicted adduct value at 48 h (Adduct 48) correlated with adductC(max), adduct T(max), Rumack-Matthews risk determination, peak aspartate aminotransferase (AST), and peak alanine aminotransferase (ALT). The pharmacokinetics and clinical correlates of APAP adducts in pediatric and adolescent patients with APAP overdose support the need for a further examination of the role of APAP adducts as clinically relevant and specific biomarkers of APAP toxicity.