Canis ISSN: 2398-2942

Amitraz toxicity

Synonym(s): Insecticide, flea collar toxicity

Contributor(s): Dawn Ruben, Patricia Talcott

Introduction

  • Amitraz Amitraz is a formamidine acaricide available as a topical preparation (dips, shampoos, lotions, sprays) for demodicosis Skin: demodectic mange and impregnated in a neck collar for tick control in dogs.
  • Amitraz toxicity occurs when the topical formulation is improperly mixed or applied or the dog ingests the tick collar.
  • Many products with amitraz also contain xylene. Some of the clinical signs associated with amitraz toxicity may be due to xylene toxicity.
  • Amitraz is not approved for use in cats.

Pathogenesis

Etiology

  • Amitraz toxicity occurs after ingestion of amitraz impregnated tick collars or following topical administration of amitraz for demodicosis, or accidental oral exposure to topical products.

Predisposing factors

General
  • Sick, elderly or debilitated animals may be more predisposed and may take longer to recover.

Pathophysiology

  • Amitraz is an a adrenergic agonist that has primary activity in the central nervous system resulting in sedation. It also is thought to have some peripheral alpha-1 and alpha-2 adrenergic activity. Amitraz is also thought to be a weak monoamine oxidase inhibitor.
  • The bradycardia associated with amitraz toxicosis is due to an alteration of autonomic function, not a direct effect of the amitraz. Death is thought to occur to due profound bradycardia and hypotension.
  • Stimulation of the postsynaptic alpha-2 receptors leads to mydriasis.
  • Smooth muscle contractility is inhibited, leading to decreased intestinal motility.
  • Insulin release is suppressed resulting in hyperglycemia.
  • LD50 is 100 mg/kg for dogs.
  • Acute oral exposure dose of 20 mg/kg in dogs has been associated with clinical signs of illness; acute oral exposure dose of 4.0 mg/kg in dogs has been associated with hypothermia.

Timecourse

  • Signs of toxicity generally develop within 2 to 6 hours of exposure or ingestion. The half-life of amitraz is about 24 hours.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Gwaltney-Brant S (2004) Insecticides and Molluscicides.I n:Clinical Veterinary Toxicology.(ed) Plumlee KH. Mosby. St. Louis, pp177-178.
  • Gfeller R W & Messonnier S P (1998) Handbook of Small Animal Toxicology & Poisonings. Mosby. St. Louis. pp 77-79.
  • Osweiler G D (1996) Toxicology. Lippincott Williams & Wilkins. Philadelphia. pp 245-246.

 

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