Abamectin: veterinary dose and monograph

At a glance

Drug class

Antiparasitic

Also known as

Avermectin B1, Abamectin (livestock endectocide)

Species with doses

Cattle and Sheep

General dose range

0.2 mg/kg SC single dose (repeat per cycle) — check the species tables for the indication

Routes

SC, PO

Last reviewed

1 October 2026

Indications

• GI nematodes (Haemonchus, Ostertagia, Trichostrongylus, Cooperia, etc.) in cattle/sheep/goats
• Lungworm (Dictyocaulus)
• Mites (mange) and lice
• Broad endo/ectoparasite control (often as combination drenches)

Abamectin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Cattle

• Endo/ectoparasites (injectable): 0.2 mg/kg SC (1 mL/50 kg of 1 %); not for lactating dairy. Label-sourced — neither Papich 5e nor Plumb’s has an abamectin monograph; follow the local product label and withdrawal.

Goats

• No reference dose for this species: Neither Papich 5e nor Plumb’s has an abamectin monograph, and the previous goat row extrapolated a higher dose with no source.

Sheep

• GI nematodes (oral drench): Often as a combination drench; check for ML resistance. Label-sourced — no Papich 5e or Plumb’s monograph; follow the product label and withdrawal. Label dose 0.2 mg/kg (200 µg/kg) PO.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Endo/ectoparasites (injectable): 0.2 mg/kg SC (1 mL/50 kg of 1 %); not for lactating dairy. Label-sourced — neither Papich 5e nor Plumb’s has an abamectin monograph; follow the local product label and withdrawal.

Contraindications

Accidental exposure of MDR1 (ABCB1-Δ) herding-breed dogs (neurotoxicity — this is a livestock drug). Environmental release near waterways (aquatic toxicity). Lactating dairy producing human milk (per product). Observe meat/withdrawal periods. Known hypersensitivity.

Species-specific warnings

Dogs: A livestock macrocyclic lactone — MDR1 (ABCB1-1Δ) breeds are highly sensitive to accidental ingestion (coma/death). Keep away from dogs.

Goats: Off-label in goats — higher dose needed, withdrawal not established; extend meat/milk withdrawal conservatively.

Adverse effects

• Transient injection-site reaction
• Neurotoxicity only at gross overdose or in MDR1-deficient animals
• Environmental toxicity to dung beetles/aquatic invertebrates

Drug interactions

• P-glycoprotein inhibitors (e.g. spinosad, ketoconazole): increased CNS exposure/toxicity
• Combination drenches: levamisole/triclabendazole add complementary spectra
• Concurrent CNS depressants: additive at high exposure

Pregnancy and lactation

Considered safe in pregnant livestock at label doses; widely used in breeding stock.

Monitoring

• Faecal egg count reduction (efficacy/resistance)
• Meat/withdrawal compliance
• Resistance surveillance (ML resistance is rising) and class rotation
• Neurologic status only if overdose suspected

Toxicity and overdose

Very wide margin in normal livestock; toxicity (mydriasis, ataxia, tremor, depression, coma) appears only at gross overdose or in MDR1-deficient dogs that access the product. Environmental toxicity to dung-dwelling and aquatic invertebrates is a class concern.

Management: No specific antidote. Supportive/intensive care; benzodiazepines for seizures; INTRAVENOUS LIPID EMULSION for severe macrocyclic-lactone neurotoxicity (lipophilic). Recovery may take days–weeks.

Clinical pearls

• An ivermectin-class livestock endectocide — broad GI-worm/lungworm/ectoparasite cover, often sold as combination drenches
• Keep away from MDR1-prone dogs (livestock product) and dispose of dung/run-off responsibly (dung-beetle/aquatic toxicity)
• Macrocyclic-lactone resistance is widespread in small-ruminant worms — use FECRT and rotate classes
• Goats need a higher dose (faster metabolism) with conservative withdrawal

Mechanism of action

Binds glutamate-gated chloride channels (and GABA channels) in nematode and arthropod neuromuscular tissue, causing chloride influx, hyperpolarisation, paralysis and death. Mammals are normally spared (channels are behind the blood–brain barrier and P-glycoprotein effluxes the drug) — the basis of MDR1 sensitivity when that protection fails.

Formulations and products

• Injectable 10 mg/mL (1 %)
• Oral drench / pour-on (livestock)
• Combination drench (with levamisole/triclabendazole)
• Abamectin injectable / drench (Various) — 1 % injectable; oral/pour-on; combination drenches, Injection / drench / pour-on

Storage

Injectable/drench/pour-on: 15–30 °C, protect from light/frost; keep away from waterways.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antiparasitics

• Afoxolaner
• Albendazole
• Allopurinol
• Amitraz
• Amprolium
• Atovaquone
• Buparvaquone
• Clorsulon

Frequently asked questions