Adsorption effects of activated charcoal on metaldehyde toxicity in rats

Metaldehyde has been widely used as a main ingredient of solid fuel for mak ing fire and slug baits in Japan. It is also marketed as a color flame tabl et for party goods (ENGELFIRE). Consequently, children have been poisoned b y eating such tablets which they mistook for candy. As a result, poison inf ormation center calls are increasing. According to POISINDEX, the treatment For metaldehyde poisoning consists in prevention of adsorption by activate d charcoal, seizure control and airway protection. However, the optimum dos e of charcoal is not established. We studied the quantitative adsorption ca pacity of activated charcoal for acute oral toxicity of metaldehyde in rats . In vivo toxicity and absorption tests for metaldehyde in Wister rats were done. The detoxifying effect of activated charcoal on metaldehyde toxicity and inhibition of metaldehyde absorption were investigated. Ratios used of po activated charcoal given 30 min after dosing to 400 mg metaldehyde/kg p o were 5:1, 2:1, 1:1, 0.5:1. Serum metaldehyde was determined by gas chroma tography in the control group (no charcoal) and the various experimental gr oups. Metaldehyde mortality was completely prevented at the ratio of 5:1. G astrointestinal absorption of metaldehyde was reduced significantly by 45.3 % in comparison to the control rats. There was no acetaldehyde detected in the serum of the metaldehyde-dosed rats. Metaldehyde poisoning may be preve nted by early po administration of activated charcoal in a ratio of >5:1 co mpared to metaldehyde. The theory that acetaldehyde is the primary toxic ag ent in metaldehyde poisoning should be re-evaluated.