What are injectable parasiticides?

Injectable parasiticides are veterinary medicines that contain antiparasitic active ingredients and are delivered by injection using a syringe with an adequate needle.

Injectables are one of the delivery forms of parasiticides most used on cattle, sheep and pigs. Usually they are ready-to-use although a few may need previous dilution. Injectables are delivered with more or less sophisticated syringes, depending on the number of animals to be treated.

Syringes for livestock. Picture fom www.alibaba.com

Once injected, the active ingredient gets into the blood stream from where it is quickly distributed throughout the organism of the treated animal. This is very important to reach parasites that can be in various body tissues or organs of the host such as the liver, the kidneys, the lungs, the heart, the muscles, the skin, etc.

Delivery by injection is also called parenteral administration, as opposed to enteral administration (oral through the mouth, or rectal through the anus).

Curiously, although there are numberless injectable antiparasitics for livestock, there are only very few injectable antiparasitics for dogs and cats: oral or topical administration are often preferred for pet antiparasitics. However, some injectable antiparasitics for livestock are also approved for use on pets in numerous countries.

The use of injectables is very scarce in industrial poultry operations, but quite common to treat fighting roosters in countries where it is practiced, e.g. in some Latin American and Asian countries.

Most antiparasitic injectables are anthelmintics (i.e. wormers) for the control of parasitic worms such as roundwormstapeworms and flukes. Many antiparasitic injectables contain macrocyclic lactones, i.e. active ingredients effective against both internal and external parasites such as licemites and maggots of various parasitic flies (bot flies, warble flies, etc.).

There are very few injectables for the exclusive control of external parasites. There are currently no injectable product for dogs that will control fleas or ticks.

Active ingredients used in injectables

Injectable wormers for cattle, sheep, goats and pigs contain macrocyclic lactones (e.g. ivermectin, doramectinmoxidectin, abamectin) and various other anthelmintics such as levamisole, closantel, nitroxinil, niclosamide, etc., often in mixtures to cover a broader spectrum of parasites. Depending on the active ingredient they can be for subcutaneous or intramuscular injection. They are used mainly against all kinds of roundworms (gastrointestinal, pulmonary, renal, etc.) as well as against flukes and tapeworms.

In the past a few organophosphates were also used as injectables against cattle grubs and other internal myiasis but this use has been completely replaced by less toxic and more effective endectocides.

Currently there are no injectables that control biting flies (e.g. horn flies, stable flies, horse flies), mosquitoes, and multi-host ticks (e.g. Amblyomma, Dermacentor, Ixodes, HaemaphysalisHyalomma or Rhipicephalus species) on any livestock or on pets. Single-host ticks such as cattle ticks cattle ticks (Boophilus=Rhipicepalus spp) can be controlled with some highly dosed macrocyclic lactones (e.g. with ivermectin and moxidectin), but such products are not approved in many countries.

Correct use of injectables

For the safe delivery of injectables several precautions have to be taken. It is very important to correctly estimate the weight of the animals. Among other reasons because some injectables have a relatively narrow safety margin, i.e., slight overdosing can easily cause toxic symptoms. To this aim it is recommended to group the animals into similar weight classes and to actually weight some of the animals in each group to confirm the dosing.

To avoid transmitting infectious microorganisms through the injecting equipment (especially the needles) it is very important to ensure cleanness of all the equipment used, and not to treat healthy animals with the same equipment as sick ones.

The syringes have to be regularly calibrated and properly maintained. It must be regularly checked that they really deliver the adjusted volume, not more and not less.

Pros and cons of injectables

Injectables are often the most popular method for administering parasiticides. They are easy to dose and to apply and many application errors associated with the use of dips, sprayspour-ons and drenches can be avoided. Injectables bear less safety risks, both for the operators and for the environment since waste disposal is usually not a problem.

Injectables don't need investments in building and maintaining constructions such as dip vats and spray races. In sheep, injectables do not leave residues in wool.

Administration of injectables is highly flexible: it can be done virtually everywhere in the property and by any weather.

Another substantial advantage of injectables is that their efficacy is completely independent of weather conditions following treatment. And in contrast with pour-ons, dips, sprays or drenches, efficacy is independent of the behavior of the treated animals. Whether the animals go into water or high and humid pastures, or they are exposed to strong sunlight, or they lick themselves or not, or they vomit, or they cough, etc., the active ingredient in the blood of the treated animal will do its job, wherever the parasite is, whatever the host does.

One disadvantage of injectables is that they can cause adverse reactions at the injection site (inflammation, pain, etc.), although normally this is not a problem for most products. But it often happens that a few animals are more susceptible to such adverse reactions than others.

Another disadvantage is the risk of transmitting infectious microorganisms if the injection equipment is not properly disinfected. It seems that this risk is particular high for horses and it is the reason why most macrocyclic lactones are not administered to horses as injectables but as oral pastes.

Another potential problem with some injectables is that they can leave excessive residues at the injection site. This can happen with active ingredients that are poorly soluble in water and can crystallize or precipitate at the injection site, which may require eliminating the tissues round the injection site after slaughtering. These inconvenuences can be more of a problem for certain breeds or in particular regions. Usually they are mentioned in the product label.

A disadvantage of all injectable macrocyclic lactones any many other injectable wormers is that they are not approved for use on dairy livestock, or only on dry animals with long wittholding periods.

Most used injectable brands

(Focus in the US, UK and Australia)

Country differences may apply: read the product label!

Selection of most used INJECTABLE antiparasitics for LIVESTOCK
Brand Targ. Species Main Pests Main Countries
With Macrocyclic Lactones
Abamectin (%)
Genesis (1%) Bo, Ov Rw, Li, Mi, Ti  AU, NZ
Paramectin (1%) Bo Rw, LiTi   AU, NZ
Ivermectin (% a.i.)
Agri-Mectin (1%) Bo, Po Rw, Li, Mi, Gr US
Animec (1%) Bo, Po Rw, Li, Mi, Gr UK+EU
Baymec (1%) Bo, Po Rw, Li, Mi, Ti AU, NZ
Bimectin (1%) Bo, Ov, Po Rw, Li, Mi, Gr US, UK+EU, CA
Bomectin (1%) Bo, Po Rw, Li, Mi, Ti AU, NZ
Ecomectin (1%) Bo, Ov, Po Rw, Li, Mi, Gr US, UK+EU
Endo-Mectin (1%) Bo, Po Rw, Li, Mi, Gr US
Ivermax (1%) Bo, Po Rw, Li, Mi, Gr US
Ivomec (1%) Bo, Ov, Po Rw, Li, Mi, Gr Worldwide
Noromectin (1%)  Bo, Ov, Po Rw, Li, Mi, Gr US, UK+EU, CA, NZ
Panomec (1%) Bo, Ov, Po Rw, Li, Mi, Gr UK
Qualimec (1%) Bo, Ov, Po Rw, Li, Mi, Gr UK+EU
Vetmec (1%) Bo Rw, Li, Mi, Ti AU
Virbamec (1%) Bo, Po Rw, Li, Mi, Gr UK+EU
Ivermectin (1%) + clorsulon (10%, benzenesulphonamide)
Animec Super Bo Rw, Flu, Li, Mi, Gr UK+EU, NZ
Baymec Gold Bo Rw, Flu, Li, Mi, Ti AU, NZ
Bimectin Plus Bo Rw, Flu, Li, Mi, Gr UK+EU
Bomectin F Bo Rw, Flu, Li, Mi, Ti AU, NZ
Genesis Ultra  Bo Rw, Flu, Li, Mi, Ti AU
Ivaclor  Bo Rw, Flu, Li, Mi, Ti AU
Ivomec Plus Bo Rw, Flu, Li, Mi, Gr, Ti Worldwide
Ivomec Super Bo Rw, Flu, Li, Mi, Gr Worldwide
Noromectin Plus Bo Rw, Flu, Li, Mi, Gr US, NZ
Virbamec Plus Bo Rw, Flu, Li, Mi, Gr, Ti AU
Virbamec Super Bo Rw, Flu, Li, Mi, Gr UK+EU
Ivermectin (%)closantel (%) = salicylanilide
Closamectin (0.5%) ( 12.5%) Bo, Ov Rw, Flu, Li, Mi, Gr UK+EU, NZ
Moxidectin (%)
Cydectin (1%) Bo, Ov Rw, Li, Mi, Gr, Ti Worldwide
Cydectin LA (2%) Ov Rw, Mi UK+EU, AU, NZ
Cydectin LA (10%) Bo Rw, Mi UK+EU, AU, NZ
Maximus LA (2%) Ov Rw, Mi AU
Doramectin (%)
Dectomax (1%) Bo, Ov, Po Rw, Li, Mi, Ti Worldwide
Eprinomectin (%) 
Longrange (5%) Bo  Rw, Mi, Gr  US, CA
With other chemical classes
Levamisole (%), imidazothiazole
Levacide (7.5%) Bo, Ov Rw UK+EU