Amitraz
Topical dip or sponge-on acaricide used for demodectic mange; systemic administration is inappropriate.
Group
Topical acaricide
Mechanism of Action
Affects parasite monoamine pathways. Mammalian alpha2-adrenergic agonist activity accounts for sedation and several toxic effects.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Demodectic mange | Reference only | TOPICAL | Every 336 h | Dilute 10.6 mL of the 19.9% concentrate in 7.5 L water to approximately 0.025%; apply 3–6 treatments. Concentration-based dipping is not a body-weight dose. |
| Refractory demodectic mange | Reference only | TOPICAL | Reported concentrations are 0.025%, 0.05% or 0.1%, applied once or twice weekly. Extreme refractory courses used 0.125% on half the body one day and the other half the next, alternating daily for 4 weeks to 5 months; adverse effects increase with concentration. |
Indications
- Demodex mite infestation.
Contraindications
- Do not administer systemically.
- Higher topical concentrations carry greater adverse-effect risk.
Interactions
- Do not combine with monoamine oxidase inhibitors such as selegiline.
- Do not combine with other alpha2 agonists.
Adverse effects
- Sedation, pruritus, polyuria and polydipsia.
- Bradycardia, hypotension, heart block, hypothermia and hyperglycemia.
- Seizures are uncommon.
Toxicity
Alpha2-related effects may be reversed with yohimbine or atipamezole.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Amitraz 19.9% dip concentrate 10.6 mL concentrate presentation; dilute before use. | Other | 199 mg / mL | TOPICAL |
Monitoring and Administration
Assess response with serial skin scrapings. Start with the standard dilution rather than refractory-case concentrations.
Store concentrate tightly sealed, protected from light, at room temperature.