Brand: INTERCEPTOR ® PLUS
CHEMICAL CLASS of the active ingredient(s):
PARASITES CONTROLLED* (spectrum of activity):
- In dogs: Heartworm prevention (Dirofilaria spp), roundworms (Toxocara canis, Toxascaris leonina), hookworms (Ancylostoma caninum), whipworms (Trichuris vulpis), tapeworms (Dipylidium caninum, Taenia spp, Echinococcus granulosus, Echinococcus multilocularis).
* Can be slightly different in some countries: read the product label!
- Dogs 2 to 8 lbs. bw: 1 tablet with 2.3 mg milbemycin oxime and 22.8 mg praziquantel
- Dogs 8.1 to 25 lbs. bw: 1 tablet with 5.75 mg milbemycin oxime and 57 mg praziquantel
- Dogs 25.1 to 50 lbs. bw: 1 tablet with 11.5 mg milbemycin oxime and 114 mg praziquantel
- Dogs 50.1 to 100 lbs. bw: 1 tablet with 23 mg milbemycin oxime and 228 mg praziquantel
- Dogs >100 lbs. bw: administer appropriate combination of tablets
* Can be slightly different in other countries: read the product label!
- LD50 (acute oral) in rats: n.a. for the tablets. 980 mg/kg for the a.i. milbemycin oxime a.i., and 2000 - 3000 mg/kg for praziquantel a.i.
- Estimated Hazard Class according to the WHO: not applicable for veterinary medicines
Never use on cats tablets approved only for use on dogs, and vice-versa. Never use on small dogs tablets approved for large animals. Learn more about tablets and their safety.
WARNING 1! All heartworm preventatives contain macrocyclic lactones, (e.g. ivermectin, milbemycin oxime, moxidectin, selamectin) which must be handled very carefully on dogs. The reason is that dogs of some breeds do not tolerate macrocyclic lactones or other medicines (e.g. emodepside) that can cross the blood-brain barrier. They can suffer more or less serious adverse effects if treated at dose rates slightly higher than the recommended ones. Consequently dosing must be as accurate as possible. This is the case for Collies and related breeds, which have a mutation in the MDR-1 gene that affects the blood-brain barrier and makes it more permeable to such compounds than in dogs without this mutation. Besides Collies, other dog breeds have shown similar problems, although the MDR-1 mutation has not been confirmed in all of them. The breeds more affected by this mutation are (% frequency): Collie (70%), Long-haired Whippet (65%), Australian Shepherd (50%, also mini), McNab (30%), Silken Windhound (30%), English Shepherd (15%), Shetland Sheepdog (15%), English Shepherd (15%), German Shepherd (10%), Herding Breed Cross (10%). Other less affected breeds are: Old English Sheepdog, Border Collie, Berger Blanc Suisse, Bobtail, Wäller. The only way to be sure that a dog breed is affected by this mutation or not, is to test for it. As more dogs are tested it is likely that the mutation is discovered in other breeds, or that the frequencies change.
WARNING 2! Heartworm preventatives stop development of microfilariae to adult worms but do not cure infections with adult worms. These preventative medicines are different from those curative anthelmintics that kill the adult worms. But preventatives may kill a few adult worms. If this happens, such dead worms may block lung vessels, which can be seriously harmful, even fatal for the pet. Consequently, heartworm preventatives are usually not administered to pets that are already infected with adult worms (hence the need for periodic diagnostic tests), because the risk of serious complications is real. The infection has first to be treated with adequate curative anthelmintics before preventative products are administered. This is however not trivial, and also risky for the same reason.
For these reasons, heartworm prevention should always be done under the supervision of a veterinary doctor.
Click here to learn more on heartworms.
You may be interested in the following articles in this site dealing with the general safety of veterinary products:
- Safety for humans
- Safety for domestic animals
- Safety for the environment
- Hazard classifications of pesticides
Risk of resistance development? Yes
There are reports of resistance or tolerance of heartworm microfilariae (Dirofilaria spp) to ivermectin and other macrocyclic lactones such as milbemycin oxime in the USA (mainly in the South). This has happened after about 20 years of very intensive use of such compounds there. This may happen elsewhere as well. Currently there are no other once-a-month treatments for heartworm prevention other than those containing macrocyclic lactones.
Are the active ingredients of this product ORIGINAL* or GENERICS**?
- Milbemycin oxime: GENERIC (introduced in the 1980s)
- Praziquantel: GENERIC (introduced in the 1970s)
*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.
COUNTRIES where this product is marketed: USA
GENERIC BRANDS available? YES, rather few, perhaps not with the same composition.
Click here to learn more about GENERIC vs. ORIGINAL drugs.
INTERCEPTOR PLUS from ELANCO is basically the same as MILBEMAX was NOVARTIS' (→ ELANCO) with a slightly different formulation. It is a broad-spectrum wormer for dogs and cats including once-a-month heartworm prevention.
Milbemycin oxime is a macrocyclic lactone effective against roundworms and some external parasites that was introduced in the late 1980s (by CIBA-GEIGY → NOVARTIS → ELANCO). It is exclusively used in pets, not in livestock or agriculture. As a general rule, due to a different pharmacokinetic behavior the anthelmintic effect is longer for milbemycin oxime than for ivermectin, although this strongly depends on the delivery form and the administered dose. A monthly treatment ensures adequate control of the roundworm species mentioned and prevents development of heartworm microfilariae.
Immature heartworms are transmitted to pets by mosquitoes that inject microfilariae (i.e. immature heartworms) during their blood meal. These microfilariae then migrate through the pet's tissues towards the blood vessels. At the recommended dose milbemycin oxime kills the migrating microfilariae in the tissues of the pets, but normally not the adult heartworms in the blood vessels. In contrast with ivermectin, at the therapeutic dose for heartworm prevention milbemycin oxime also controls several important parasitic roundworms (Toxocara canis, Toxascaris leonina), hookworms (Ancylostoma caninum) and whipworms (Trichuris vulpis) in dogs.
Praziquantel is a veteran isoquinoline anthelmintic introduced in the 1970s (by BAYER). Praziquantel adds efficacy against tapeworms (e.g. Dipylidium caninum, Taenia pisiformis, Echinococcus granulosus, Echinococcus multilocularis) but has no efficacy whatsoever against roundworms, hookworms or whipworms. It is the anthelmintic most vastly used against tapeworms in pets. There are hundreds of antiparasitic brands for pets containing praziquantel.
For an overview and a list of the most popular pet wormers click here.
This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics.
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