The dosage form characteristics of avermectins
Avermectins is a new type antiparasitic agent that is safe, efficient and can both kill endoparasite and ectoparasite. Ivermectin is generated after the selective hydrogenation reduction of abamectin insecticide, which will have more stable performance.
Avermectins has two outstanding characteristics: by using it one time, it can both kill nematodes in vivo and arthropod parasite in vitro, which has high expelling parasite and insecticidal efficiency as well as is safe and efficient; it has unique anti-parasitic mechanism and has no cross tolerance with other anti-parasitic drugs.
After extensive clinical application, abamectin and ivermectin that produced in China have been accepted more and more due to its high efficiency and security, especially that they will have indispensable effect on preventing arthropod ectoparasite. Compared with foreign countries, the expelling parasite effect and increased weight benefit of abamectin and ivermectin that produced in China will not differ a lot. Therefore, by using abamectin and ivermectin that produced in China, it can not only ensure control efficiency, but also can reduce expelling parasite cost and can improve comprehensive economic benefit. As abamectin and ivermectin have various dosage forms, they can be used according to practical needs.
a. About the dosage: no matter choose abamectin, ivermectin or other kinds of dosage forms, they should reach to certain dosage and should not be used too lot. Especially for dogs, cats, rabbits and other infant animals, the excessive dosage will be easy to cause poisoning; regarding the pregnant livestock, we should use drugs more accurately before parturition so as to ensure the safety of fetus. Generally speaking, the recommended dose of avermectins (according to effective content) is as follows: 0.3mg/kg.b.w for pig and 0.2mg/kg.b.w for other animals.
b. About the dosage form: abamectin and ivermectin have various dosage forms, which mainly include injection, oral liquid, ointment, tablet, powder, capsule, pour-on solution, premix and so on. Usually, it will be convenient as well as can save time and effort by using abamectin and ivermectin with intestinal drug delivery method; regarding the livestock that are infected with arthropod ectoparasite, injection can be used, which should be used again after 10 days.
c. About animals: Regarding small animals (such as dogs, cats, rabbits and foxes), infant animals and pregnant livestock, ivermectin preparation (0.1 percent of ivermectin injection) can be used, which can not only ensure accurate dosage, but also can increase the safety factor when using drugs.
Regarding cattle, sheep and other ruminants, as some of the microorganisms in the rumen can resolve avermectins into substances that have low resistance to parasites, part of the drugs will be damaged. Therefore, when killing the parasites of ruminants, abamectin and ivermectin injections should be used. However, regarding scattering raising households, intestinal drug delivery will be undoubtedly most convenient and most practical.
Regarding pig farms, injection or premix can be used according to practical needs. It can be seen from the statistical data of pig farms that the feed consumption is about 5 percent of body weight in the delectation period of pig every day; from delectation to slaughter period, the feed consumption is about 3 percent of body weight every day. Therefore, each kilogram of feed should contain 7.5mg effective content of avermectins (7.5mg/kg.F) and should be injected in one day. It can also be added in the feed with 2ppm effective content, which can be continuously used in feeding pigs for 7 days. Premix is easy to use as well as can save time and effort, but it has lower effect on preventing sarcoptes suis compared with abamectin and ivermectin injections.
d. About comprehensive measures: medical treatment is the main method of controlling parasitic disease of animals. However, if we do not take certain environmental health measures, even the best anti-parasitic drugs will be of no use. Therefore, when preventing parasitic disease, we should pay attention to the environmental health of livestock farm. As most of the drugs cannot fully kill the eggs of mature insect uterus, if the excreta of disintegrating insect are spread everywhere after expelling parasite, it will seriously pollute the surrounding environment of livestock farm. Therefore, in order to ensure desinsectization effect, we should gather the excreta of livestock in time and dispose them together when expelling parasite with drugs so as to reduce repeated infection of parasite eggs.