Effectiveness of early activated charcoal administration in managing single-dose paracetamol overdose: a retrospective review in Hong Kong.

Introduction: This study aimed to assess the effectiveness of early activated charcoal administration for the management of single-dose paracetamol overdoses in Hong Kong.

Methods: We retrospectively analyzed electronic records from 2010 to 2020 to identify patients with paracetamol overdose. The inclusion criteria comprised individuals over the age of 12 years with a known toxic dose (≥7.5 g) of a standard paracetamol preparation, available serum paracetamol concentration, and a known ingestion time within 4 h. Patients were categorized into either an activated charcoal group or a no activated charcoal group. The paracetamol ratio (serum paracetamol concentration divided by the corresponding concentration on the 150 mg/L at 4 h treatment line) and the need for acetylcysteine were compared. The effect of the timing of activated charcoal administration was also investigated.

Results: Of the 1,274 screened cases, 601 met the inclusion criteria. Activated charcoal was administered to 366 patients at a median time of 89 min (IQR: 56-134 min) post-ingestion, including 140 who received pre-hospital activated charcoal at a median time of 55 min (IQR: 56-134 min). Acetylcysteine was required by 18.3% of the activated charcoal group and 35.3% of the no activated charcoal group. Odds ratios for acetylcysteine requirement decreased with earlier administration: 0.23 at 1 h (95% CI: 0.11-0.45; P <0.001), 0.24 at 1-2 h (95% CI: 0.13-0.42; P <0.001) and 0.49 at 2-3 h (95% CI: 0.25-0.94; P = 0.037).

Discussion: Pre-hospital administration of activated charcoal is now feasible in Hong Kong. Although activated charcoal is not a life-saving intervention, it appears to reduce the need for antidote treatment. Early activated charcoal administration is associated with reducing acetylcysteine requirements in paracetamol overdoses up to 3 h post-ingestion. Elderly patients showed higher acetylcysteine needs (adjusted OR: 4.31; 95% CI: 1.53-11.96; P = 0.005).

Conclusion: Early activated charcoal administration, including pre-hospital use, was significantly associated with a reduced acetylcysteine requirement for paracetamol overdose, with benefits observed up to 3 h post-ingestion.