AMIRAZ 20% EMULSIFIABLE CONCENTRATE

Indications

• Acaricide for veterinary use
• Treatment of certain human conditions such as ADHD
• Potential use in obesity management

Dosage

Children: Refer to BNF for Children for specific paediatric dosing guidelines.

Adults: Refer to BNF for specific dosing recommendations, as dosing may vary based on indication and patient factors.

Mechanism of action

Amitraz exerts its pharmacological effects primarily by acting as an agonist at alpha-2 adrenergic receptors in the central nervous system. This action leads to a decrease in norepinephrine release and results in sedation, analgesia, and decreased sympathetic outflow. Additionally, it has been shown to inhibit monoamine oxidase, which may contribute to its effects on neurotransmitter levels. The drug also affects the octopaminergic system in insects, which is critical for their motor function and behavior.

Pharmacodynamics

Amitraz demonstrates sedative and analgesic properties due to its central nervous system activity. Its interaction with alpha-2 adrenergic receptors results in decreased heart rate, reduced blood pressure, and drowsiness. In addition, its role as a monoamine oxidase inhibitor may enhance the levels of certain neurotransmitters, potentially influencing mood and behavior. The overall pharmacodynamic profile indicates a complex interaction with both adrenergic and non-adrenergic pathways.

Pharmacokinetics

Amitraz is absorbed well following administration and can cross the blood-brain barrier due to its lipophilic nature. It undergoes extensive metabolism in the liver, primarily through oxidation and conjugation. The elimination half-life can vary, but metabolites are typically excreted in urine. Factors such as age, liver function, and concurrent medications may influence its pharmacokinetic parameters.

Contra-indications

• Hypersensitivity to amitraz or any of its components
• Pregnancy
• Severe depression of the central nervous system
• Concurrent use with monoamine oxidase inhibitors

Adverse effects

• Sedation
• Ataxia
• Vomiting
• Diarrhoea
• Skin rash
• Hypotension
• Bradycardia

Interactions

• May interact with central nervous system depressants, leading to enhanced sedation
• Concurrent use with monoamine oxidase inhibitors may increase the risk of hypotension and bradycardia

Precautions

• Use with caution in animals with compromised central nervous system function
• Monitor for signs of toxicity, especially in young, elderly or debilitated patients
• Not recommended for use in pregnant or lactating animals

Pregnancy

Amitraz is contraindicated during pregnancy due to potential risks to the fetus.

Breast-feeding

Caution is advised when administering to lactating individuals as it may be excreted in milk.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Topical solution
• Emulsifiable concentrate