Products
Amitraz is available in the form of a collar for dogs (Preventic) and as a spray/bath solution or emulsion (Taktic). It is marketed exclusively as a veterinary drug in many countries and has been approved since 1992.
Structure and properties
Amitraz (C19H23N3, Mr = 293.4 g/mol) is a formamidine derivative and belongs to the benzamidine group. It exists as a crystalline substance and exhibits a white to yellowish color. Since it is not stable in water, aqueous suspensions can decompose and become toxic during prolonged storage.
Effects
Amitraz (ATCvet QP53AD01) is insecticidal and acaricidal. It is effective against ectoparasites, including mites (especially ), lice, flies, and all developmental stages of ticks. Against fleas, amitraz is effective only in combination with other active ingredients.
Mechanism of action
Amitraz is an antagonist at the octopamine receptors in the nervous system of parasites. Its action is based on blockade of these receptors, leading to death by hyperexcitation, paralysis, and interruption of the blood meal. In warm-blooded animals, it has an agonistic effect at the α2-adrenoreceptors and also has a weak antiserotoninergic effect. This is also the basis for the possible adverse effects. Resistance has been reported.
Indications
Amitraz is approved in dogs for the prevention and treatment of tick infestation. In cattle, cows, pigs, sheep, and goats, it is used to treat and prevent infestations of mites, lice, flies, and ticks. It is applied externally. In other countries, amitraz in the form of an emulsion is often used to treat demodicosis in dogs (and also cats). This is an excessive infestation of hair follicle mites.
Dosage
According to the SmPC. Amitraz shows a dose-dependent effect. In dogs, amitraz is used in the form of a collar. This can be worn either only during the tick season from the end of winter to the end of fall or preventively throughout the year. Cattle and pigs are sprayed with a freshly prepared spray solution until they are dripping wet all over their bodies. For sheep and goats, a bath treatment with a bath solution freshly prepared for this purpose is suitable. Animals should remain in the bathing solution for 30 seconds and should be head dipped at least once. The user must wear waterproof protective clothing, gloves, and a protective mask during spray or bath treatment with amitraz.
Contraindications
Amitraz is contraindicated in hypersensitivity, horses, cats, and Chihuahuas. The dog collar should not be used on sick, pregnant or lactating dogs. Thirsty, exhausted and sick animals should be excluded from treatment with the spray or bath solution. Amitraz is a fish poison and therefore should not be allowed to enter water bodies. Refer to the drug label for complete precautions.
Interactions
Amitraz should not be used with other insecticides, acaricides, or α2-agonists.
Adverse effects
Adverse effects result from the α2-agonist and weak antiserotoninergic effects of amitraz on warm-blooded animals. These include dullness, lethargy, low blood pressure, low pulse, hypothermia, loss of appetite, vomiting, increased blood glucose, frequent urination, and indigestion. Due to the occurrence of elevated blood sugar and and frequent urination, there is a risk of confusion with diabetes. In dogs, after applying the collar, irritation of the skin and mucous membrane may occur in the form of itching, eczema, hair loss, pustule formation, but also restlessness, conjunctivitis and allergies. In case of overdose, atipamezole can be administered as an antidote. This is an α2-antagonist.