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Amitraz Toxicosis 49

may result in clinical signs. Mild effects also ○ Botulism inhibitors (SSRIs) may display more severe
have been reported in patients with topical ○ Tick paralysis effects due to compounded effects.
VetBooks.ir inflamed or broken skin are more at risk. Initial Database Possible Complications Diseases and Disorders
exposure to correct dosages. Animals with
Temperature, pulse, respiratory rate, blood
Foreign body obstruction associated with collar
Ingestion of portions of amitraz-impregnated
pressure, and electrocardiogram should be
collars may cause significant toxic effects.
included in initial assessment. Specific clinico- ingestion
GEOGRAPHY AND SEASONALITY pathologic changes definitive for amitraz toxi- Recommended Monitoring
Increased frequency of amitraz toxicosis may cosis have not been identified. Hyperglycemia Ongoing monitoring of temperature, pulse,
correlate with warm seasons and locations may result from inhibition of insulin release. respirations, and blood pressure is recom-
in which the environmental tick burden is Electrolyte alterations may be due to vomiting mended. Monitoring of blood glucose concen-
higher. and/or diarrhea, and azotemia may be present tration may be helpful, but administration of
if the patient is dehydrated (correlate with urine insulin for hyperglycemia is not generally
Clinical Presentation specific gravity before fluid therapy to help recommended.
HISTORY, CHIEF COMPLAINT exclude renal insufficiency/failure, Addisonian
Chief presenting complaint is often significant crisis, etc.). CBC abnormalities are absent or PROGNOSIS & OUTCOME
lethargy, depression, and/or ataxia. Pet owners nonspecific.
may also identify ptyalism, vomiting/diarrhea, For mildly to moderately affected patients,
mydriasis, and hypothermia. Advanced or Confirmatory Testing particularly those with topical exposures,
Radiographic imaging may reveal the collar prognosis is good, with no expected long-term
PHYSICAL EXAM FINDINGS buckle in ingestion cases, but collar fragments ill effects. In patients with high-dose exposures,
Mild cases due to topical exposure may display may not be visible. Upper GI endoscopy may prognosis is guarded, particularly in case of
only mild lethargy and depression. More severe identify ingested collar segments. Laboratory ingestion that may exceed the LD50.
cases can display hypothermia, hypotension, testing for amitraz is inconsistently available
bradycardia, vomiting, diarrhea, ileus, coma, through diagnostic laboratories, and turn- PEARLS & CONSIDERATIONS
and seizures. around time may preclude utility in the
emergency setting. Comments
Etiology and Pathophysiology Although clinical signs can be significant, many
• Amitraz is an alpha-2 adrenergic agonist, TREATMENT cases of amitraz toxicosis have a positive
and clinical signs and physiologic effects outcome.
generally stem from central nervous system Treatment Overview
(CNS) effects, including subsequent effects In topical exposures, removal of the product via Prevention
on the cardiovascular and gastrointestinal bathing with dish soap is an important step in Prevent pet access to loose collars and removed
(GI) systems. resolution of signs. However, this step should collar segments. The use of amitraz-containing
• Amitraz is also a weak inhibitor of be delayed until the patient is clinically stable, products on cats, toy dogs, young or geriatric
monoamine oxidase (MAO) activity in the and care must be taken to ensure adequate animals should be avoided if possible.
CNS. thermoregulation during and after bathing.
In ingestion cases, passage or removal of the Technician Tips
DIAGNOSIS collar segments is important for permanent Due to the reduced ability to thermoregulate,
resolution of clinical signs, but endoscopic or patient body temperature should be monitored.
Diagnostic Overview surgical intervention may be limited by patient Warming or cooling devices should be used
Amitraz toxicosis is suspected due to the clinical status. with care and close supervision. Bathing of
combination of clinical signs and a history patients with topical exposure and compromised
of exposure or potential exposure to amitraz- Acute General Treatment thermoregulation should be done with caution
containing products. Sources report LD50 Reversal of the alpha-2 adrenergic agonist and delayed until the patient is stabilized.
(lethal doses capable of killing 50% of test effects by administration of atipamezole Continued monitoring of the pet’s temperature
animals) of 100 mg/kg in dogs, although mild (preferred) or yohimbine is expected to result after bathing (i.e., during drying period) is
clinical signs have been reported with topical in significant improvement in clinical signs, important.
exposure at therapeutic dosages. although repeated dosing may be necessary.
Signs may persist for several days, particularly Client Education
Differential Diagnosis if waiting for ingested collar segments to pass. Pet owners using amitraz-impregnated collars
• Other toxicants Intravenous fluid support is recommended in for tick prevention should be thoroughly
○ Opioids/narcotics hypotensive patients, but diuresis does not educated about the risk of ingestion to pets
○ Alcohols (ethanol, methanol) speed the elimination of amitraz from the and children.
○ Marijuana body. Amitraz adsorbs to activated charcoal,
○ Muscle relaxants such as baclofen but the alpha-2 agonist effects may result in SUGGESTED READING
○ Benzodiazepines ileus, prolonging passage and elimination of Andrade SF, et al: The comparative efficacy of
○ Barbiturates the activated charcoal. yohimbine and atipamezole to treat amitraz
○ Antidepressant and anxiolytic medications intoxication in dogs. Vet Hum Toxicol 45:124-127,
○ Ivermectin Chronic Treatment 2003.
• Systemic diseases/conditions If the patient survives the topical or ingestion AUTHOR: Amy Schnelle, DVM, MS, DACVP
○ CNS disease or trauma exposure, long-term effects are generally not EDITOR: Tina Wismer DVM, MS, DABVT, DABT
○ Hepatoencephalopathy expected.
○ Sepsis, especially secondary to significant
GI disease/perforation Drug Interactions
○ Myasthenia gravis Patients receiving or concurrently exposed to
○ Addisonian/hypoadrenocortical crisis MAO inhibitors or selective serotonin reuptake

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