PHARMACOLOGICAL INFORMATION
ATCvet code : QP 54 AA 01
Pharmacodynamics
Ivermectin is a macrocyclic lactone derivative and acts by inhibiting nerve impulses. It binds selectively and with high affinity to glutamate-gated chloride ion channels which occur in invertebrate nerve and muscle cells. This leads to an increase in the permeability of the cell membrane to chloride ions with hyperpolarization of the nerve or muscle cell, resulting in paralysis and death of the relevant parasites. Compounds of this class may also interact with other ligand-gated chloride channels, such as those gated by the neurotransmitter gamma-aminobutyric acid (GABA). The margin of safety for compounds of this class is attributable to the fact that mammals do not have glutamate-gated chloride channels. The macrocyclic lactones have a low affinity for other mammalian ligand-gated chloride channels and they do not readily cross the blood-brain barrier.
Pharmacokinetics
After oral administration of the recommended doses to horses, the following parameters were observed: Cmax of 48.79 ng/ml, Tmax of 5.5 hours, elimination half-life of 61 hours. Ivermectin is eliminated primarily via the faeces.