ATC Vet Code: QP54 AA 01

Ivermectin is a 22,23-dihydro derivative of an avermectin (which is a fermentation product produced by Streptomyces avermitilis) and consists of 2 homologues: B1a and B1b. It is a highly effective parasiticide with nematocidal, insecticidal and acaricidal activity documented in a wide range of domesticated animals.

Avermectins interact selectively and with high affinity with glutamate-gated chloride ion channels, which only occur in invertebrate nerve and muscle cells. This increases membrane permeability to chloride ions, causing irreversible neuromuscular blockades in nematodes, followed by paralysis and death. The macrocyclic lactones have a low affinity for other mammalian ligand gated chloride channels and they do not readily cross the blood brain barrier.

After administration orally to sheep at a dose of 200 µg/kg, maximum plasma concentration of ivermectin was 5.99 µg/ml at 16.2 hours after administration and the elimination half-life was approximately 25 hours.