Veterinary Drug Handbook (VDH) is the reference veterinarians turn to when they want an independent source of information on the drugs that are used in veterinary medicine today.


Chemistry - A diamide topical antiparasitic agent, amitraz is pale yellow with a melting point of86°-87°C. It is sparingly soluble in water, but soluble in most organic solvents. It is non-hygroscopic and relatively stable to heat.

Storage, Stability, Compatibility

Compatibility with other agents have apparently not been determined. Do not mix with other antiparasiticides.

Pharmacology - AMITRAZ

The pharmacologic action of amitraz is not well understood. It may have effectson the CNS of susceptible organisms. It apparently also possess alpha-2 adrenergic activity.
Amitraz can cause a significant increase in plasma glucose levels, presumably by inhibiting insulinrelease via its alpha 2-adrenergic activity. Yohimbine (alpha 2 blocker) can antagonize this effect).

Uses, Indications

In dogs, amitraz is used topically primarily in the treatment of generalizeddemodicosis. It is also used as a general insecticidal/miticidal agent in several other species (seelabel information).

Pharmacokinetics - AMITRAZ

No information located.

Contraindications, Precautions, Reproductive Safety

Safety has not been demonstrated indogs less than 4 months of age. The manufacturer of Mitaban® does not recommend use in theseanimals. Toy breeds may be more susceptible to CNS effects (transient sedation); lower dose rates(1/2 of recommended) has been recommended in these breeds. Because of the drug's effects onplasma glucose, use with caution in brittle diabetic patients.
Reproductive safety has not been established. Use only when benefits outweigh potential risks oftherapy.

Adverse Effects, Warnings

The most commonly reported adverse effect after amitraz topicaladministration is transient sedation that may persist for up to 72 hours (24 hours is usual). Iftreating around eyes, use an ophthalmic protectant (e.g., petrolatum ophthalmic ointment) beforetreating. Do not use if dog has deep pyodermas with drainage tracts; postpone application untillesions improve after treating with antibiotic and shampoo therapy.
Amitraz can be toxic to cats and rabbits and it is probably best to avoid its use in these species.

Overdosage, Acute Toxicity

Amitraz may be toxic if swallowed (by either animals or humans).
Beagles receiving 4 mg/kg PO daily for 90 days, demonstrated transient ataxia, CNS depression, hyperglycemia, decreased pulse rates and lowered body temperature. No animals died.
Amitraz toxicity can be significant if amitraz-containing insecticide collars are ingested. Treatmentshould consist of emesis, retrieval of the collar using endoscopy if possible and administration ofactivated charcoal and a cathartic to remove any remaining collar fragments. Because of the risk ofan increased chance of gastric dilatation, gastrotomy may not be a viable option. Yohimbine at adose of 0.11- 0.2 mg/kg IV (start with low dosage) may be of benefit for overdose effects. Becauseyohimbine has a short half-life it may need to be repeated, particularly if the animal has ingested anamitraz-containing collar that has not been retrieved from the GI tract. Atipamezole has also beenused to treat amitraz toxicity; refer to that monograph for more information. Contact a poison centerfor more information, if necessary.

Drug Interactions

Because of their immunosuppressive effects, corticosteroids and otherimmunosuppressant drugs (e.g., azathioprine, cyclophosphamide, etc) should not be used inanimals with demodicosis.

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