28. Endectocides (macrocyclic lactones)

Question 1

Macrocyclic lactones. Drugs

Answer 1

• IVERmectin
• DORAmectin
• SELAmectin
• EPRINOmectin
• MOXIdectin
• milbemycin oxime

Question 2

Macrocyclic lactones. Mechanism of action

Answer 2

• potentiation of inhibitory transmitters by binding to glutamate- and GABA-gated chloride channel receptors in nematode and arthropod nerve cells -> opening of channels -> influx of Cl- ions
• paralyse the pharynx, body wall and uterinal muscles of nematodes

Question 3

Macrocyclic lactones. Antihelmintic spectrum

Answer 3

• Adult, immature NEMATODES, including hypobiotic larvae, microfilariae /+ arthropods
• cestodes, trematodes are not sensitive

Question 4

Macrocyclic lactones. PK

Answer 4

• lipophilic compounds, good absorption, wide distribution (BBB)
• accumulation in fatty tissue, long-lasting effect (2-4 weeks)
• residues in meat (WP: SC - 1,5-2months, PO, topical - >2 weeks)
• in milk only moxidectin (WP 5 days) and eprinomectin (WP 0 days) in lactating cows

Question 5

Macrocyclic lactones. Side effects

Answer 5

• TI is moderately-large
• abamectin and moxidectin are contraindicated in calves and foals <4 months old
• mammalian safety depends on P-glycoprotein activity in the BBB. NS signs including depression, muscle weakness, blindness, coma and death were observed, esp in collies

Question 6

Macrocyclic lactones. Application

Answer 6

• SC - injection in Ruminants
• PO - swine premix, horses paste
• dermal - pour-on, spot-on

Question 7

Macrocyclic lactones