VPT 421: Veterinary Toxicology (2+0)

METALDEHYDE

• This polymer of acetaldehyde is used as a snail or slug bait, to which dogs and livestock may be exposed.
• Toxic effects are due to absorption of limited acetaldehyde from metaldehyde hydrolysis in the stomach, but primarily to the metaldehyde itself.
• Signs range from salivation and vomiting to anxiety and incoordination with muscle tremors, fasciculations, and hyperesthesia leading to continuous muscle spasms, prostration, and death.
• Generally, the muscle spasms are not initiated by external stimuli, but excessive muscular activity is common, often producing high body temperatures.
• Differential diagnoses include strychnine poisoning and anticholinesterase insecticide toxicity.
• The finding of metaldehyde bait or pellets in the vomitus and the possible odor of acetaldehyde from stomach contents or on the animal’s breath may assist in diagnosis.
• Treatment is most effective if initiated early.
• Further toxicant absorption should be prevented by induced emesis, gastric lavage, and oral dosing with activated charcoal.
• Hyperesthesia and muscle activity may be controlled with diazepam or light barbiturate anesthesia and muscle relaxants as needed.
• IV fluid therapy with lactated Ringer’s solution or 5% glucose helps to promote toxin excretion and to combat dehydration and the acidosis induced by the excessive muscle activity.
• Continuous supportive care is important.