VPT 421: Veterinary Toxicology (2+0)

ANTICOAGULANT RODENTICIEDS
(Warfarin and congeners)

• The anticoagulant rodenticides are a potential hazard for all mammals, birds, and possibly other species.
• The susceptibility varies among animal species and the toxicity of the compounds also varies.
• Dogs and cats are most frequently involved, with occasional problems encountered in swine, ruminants, horses, pet birds, rodents and rabbits.
• Pets and wildlife may be poisoned directly by eating the bait or indirectly by eating the poisoned rodents.
• In domestic animals, intoxication is the result of feed contamination, malicious use and feed mixed in the equipment used to prepare rodent bait.
• Although consumption of warfarin-poisoned rodents or birds by carnivores does not appear to present a likely hazard for the predator, consumption of tissues from diphacinone-poisoned animals has caused secondary poisoning in eagles, rats, dogs and mink.
• Secondary toxicity may rarely occur with other second-generation anticoagulants.
• All anticoagulants have the basic coumarin or indanedione nucleus.
• The 'first-generation' anticoagulants (warfarin, pindone, coumafuryl, coumachlor, isovaleryl indanedione, and others less frequently used) require multiple feedings to result in toxicity.
• The 'intermediate' anticoagulants (chlorophacinone and in particular diphacinone) require fewer feedings than “first-generation” chemicals, and thus are more toxic to nontarget species.
• The 'second-generation' anticoagulants (brodifacoum and bromadiolone) are highly toxic to non target species (dogs, cats and potentially livestock) after a single feeding.