Neurotoxicity of Rodenticides

Rodenticides are a heterogeneous group of compounds that exhibit markedly different toxicities to humans and rodents. Table 23.1 lists the effects and neurological presentations for different examples. According to the Toxic

304 N.B. Katz, O. Katz, and S. Mandel Table 23.1. Effects of specific rodenticides.

Chemical (brand name) Sodium monofluoroacetate A-3-pyridylmethyl-Np-nitrophenyl urea [PNU] (Vacor) Strychnine

Barium compounds

Yellow phosphorus Arsenic compounds

Zinc phosphide Bromethalin


Warfarin-like anticoagulants and brodifacoum

Effects Poisons the Krebs cycle Destroys the pancreatic beta cell

Antagonist of glycine at the postsynaptic spinal cord motor neuron Causes potassium redistribution (intracellular influx), may lead to hypotonia Causes chemical burns, hemolysis React with sulfhydryl groups of multiple enzymes Causes hemolysis Identified as a mitochondrion poison (uncouples oxidation) Causes ischemia (via vasoconstriction) Cause hemorrhages

Possible neurological presentation Dizziness, weakness, nausea Dizziness, weakness, nausea

Seizure-like, extensor posturing with risus sardonicus

Headache, weakness, nausea, shortness of breath, brain anoxia

Agitation, weakness

Nausea, vomiting, weakness

Nausea, vomiting, weakness

Nausea, vomiting, weakness

Dizziness, seizure-like presentation possible

Multiple dose- and organ-dependent complaints

Source: Data from Feldman (1), Carod Artal (6), and Van Sittert and Tuinman (9).

Exposure Surveillance System (TESS) of the American Association of Poison Control Centers (AAPCC), 20,300 human exposures to rodenticides were reported in 1 year (1998) (9,10).

Management of toxicity induced by rodenticides is toxin-specific and usually involves emergency care for acute exposure. Strychnine may be of special interest to a physician, due to its unique and well-studied mechanism of toxicity. This plant alkaloid is no longer widely used in the United States but is more widely used in the developing countries. Consider strychnine toxicity if an individual presents with generalized seizure-like appearance, with or without loss of consciousness. Of note is the fact that strychnine may be used as an adulterant in street drugs, especially those sold as lysergic acid diethylamide (LSD) (9).

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