Eprinomectin is a semisynthetic avermectin that consists
of a mixture of two homologues, eprinomectin
B1a (4 epi-acetylamino-4 -deoxy-avermectin B1; 90%) and
eprinomectin B1b (10%).Eprinomectin was developed
as a topical endectocide for all categories of cattle
including lactating dairy cattle, and the process by
which eprinomectin was selected for further development
has been described (90). Briefly, several hundred avermectin/
milbemycin analogues were screened in a sheep
model for efficacy against a range of endoparasites and
in lactating dairy cows for a low milk:plasma partitioning
ratio. Themilk:plasma ratio for eprinomectin is <0.2; ivermectin,
by comparison, partitions equally between milk
and plasma.
Eprinomectin is an avermectin with anthelmintic and insecticidal activities. It is comprised of eprinomectin B1a and eprinomectin B1b . Eprinomectin (≥0.08 mg/kg, applied topically) reduces worm burden by 99% or more in bovine models of adult H. placei, O. ostertagi, T. axei, Cooperia punctata, N. helvetianus, O. radiatum, or D. viviparus infection. It also reduces parasite burden in bovine models of horn fly (H. irritans) or mange mite (C. bovis) infestation, as well as in cows naturally infested with lice (L. vituli), when applied topically at doses ranging from 0.16 to 0.5 mg/kg. Formulations containing eprinomectin have been used in the treatment and control of a variety of endo- and ectoparasites in cattle.
Eprinomectin is a mixture of eprinomectins B1a and B1b in a 9:1 ratio, produced from a mixture of avermectin B1a and B1b. Eprinomectin is used commercially as a topical endectocide (insecticide, miticide and nematocide) for cattle, including lactating dairy cows. Like all avermectins and milbemycins, eprinomectin acts by binding to parasite glutamate-gated chloride ion channels and disrupts neurotransmission leading to paralysis and death of the parasite, mite or insect.
A mixture of semi-synthetic Avermectins; containing 90% or more of component B1a and 10% or less of component B1b. Antiparasitic
A mixture of Eprinomectin B1a and B1b showing anti-anthelintic activity
Eprinex [Veterinary](Merial).
Veterinary Drugs and Treatments
In cattle, eprinomectin is indicated for a variety gastrointestinal
roundworms including
adult and L4 stages of Haemonchus placei,
Ostertagia ostertagi, Trichostrongylus axei and colubriformis,
Cooperia oncophora/punctata/surnabada, Nematodirus helvetianus,
Oesophagostomum radiatum, Bunostomum phlebotomum, and
Trichuris spp. (adults only); cattle grubs; lice; mange mites; horn
flies (for 7 days after treatment), and lungworms (Dictyocaulus
vivaparus—for 21 days after treatment).
Topical eprinomectin may be useful for the topical treatment
of ear mites (Psoroptes cuniculi) in rabbits. One small study (6 subjects)
showed partial response when rabbits were dosed at 5 mg/kg
topically, twice at 14 day intervals. (Ulutas, Voyvoda et al. 2005)
Acute oral LD50 for rats: 55mg/kg
