Suspected metaldehyde slug bait poisoning in dogs: a retrospective analysis of cases reported to the Veterinary Poisons Information Service.

A retrospective analysis of telephone enquiries to the Veterinary Poisons Information Service found 772 cases with follow-up concerning suspected metaldehyde slug bait ingestion in dogs between 1985 and 2010. Half the enquiries occurred in the summer months. The amount and strength of the slug bait ingested was rarely known. In 56, cases the quantity consumed was estimated and was on average 229.6 grams of bait. Clinical signs developed in 77.3 per cent of dogs; common signs were convulsions, hypersalivation, twitching, hyperaesthesia, tremor, vomiting, hyperthermia and ataxia. Only 4.6 per cent of dogs developed hepatic changes, and only one developed renal impairment. The average time to onset of signs was 2.9 hours post-ingestion, with 50.3 per cent of dogs developing effects within one hour. Increased muscle activity (twitching, convulsions) lasted on average 15.2 hours. Recovery time was reported in 61 cases and occurred on average at 39.3 hours. Common treatments were gut decontamination, anticonvulsants, anaesthetics and intravenous fluids. Of the dogs that were treated with sedatives, 45.8 per cent required more than one sedative or anaesthetic agent. Methocarbamol was rarely used, probably due to unavailability. The outcome was reported in 762 dogs; 21.7 per cent remained asymptomatic, 61.7 per cent recovered and 16 per cent of dogs died or were euthanased. Where known (only six cases), the fatal dose of bait ranged from 4.2 to 26.7 g/kg (average 11.8 g/kg).