Doramectin is an avermectin-class macrocyclic lactone used chiefly for nematode and ectoparasite control in livestock. Injectable and topical veterinary products target gastrointestinal worms, lungworms and selected arthropods. It has also been used extra-label for certain mite infestations in dogs and cats, with species-specific differences in clinical experience and tolerance.
Doramectin binds parasite glutamate-gated chloride channels and increases chloride permeability in susceptible nerve and muscle cells. Hyperpolarization reduces excitability, causing impaired feeding, paralysis and eventual parasite death. Activity against these invertebrate channels accounts for its effects on nematodes and selected arthropods. The precise duration of parasite control depends on the formulation, parasite species and stage.
Up to 161 days; Do not use in: Known macrocyclic-lactone sensitivity; Reported courses 5–23 weeks; use an appropriate formulation and assess ABCB1 risk.
Generalized demodicosis
600 mcg/kg
PO
Every 24 h
Do not use in: ABCB1/MDR1 drug sensitivity; Change therapy if there is no improvement after 60 days.
Cat
Use / stage
Dose
Route
Schedule
Instructions
Mite infestation
200–270 mcg/kg
SC
Once
Do not use in: Known macrocyclic-lactone sensitivity
Historical fixed mite treatment
Reference only
SC
Do not use in: Known macrocyclic-lactone sensitivity; A fixed 0.1 mL of 1% injection is reported without patient weight; it is not a universal feline dose.
Demodicosis
600 mcg/kg
SC
Every 168 h
D. cati or D. gatoi; assess response and monitor for macrocyclic-lactone neurotoxicity.
Cattle
Use / stage
Dose
Route
Schedule
Instructions
Parasites
0.2 mg/kg
IM, SC
Once
Do not use in: Known macrocyclic-lactone sensitivity
Parasites
0.5 mg/kg
TOPICAL
Once
Do not use in: Known macrocyclic-lactone sensitivity; Pour-on along the dorsal midline.
Pig
Use / stage
Dose
Route
Schedule
Instructions
Parasites
0.3 mg/kg
IM
Once
Do not use in: Known macrocyclic-lactone sensitivity
