FORMULATION: «liquid wormer» for oral administration

ACTIVE INGREDIENT(S): PYRANTEL (as pamoate salt) 4.54 mg/mL



PARASITES CONTROLLED* (spectrum of activity)


  • Dogs: 5 mL (full teaspoon) per 10 lbs. (equivalent to 5.0 mg/kg pyrantel base)

* Can be slightly different in some countries: read the product label!


  • LD50 (acute oral) in rats: n.a. for the liquid. >5000 mg/kg for pyrantel
  • Estimated Hazard Class according to the WHO: not applicable for veterinary medicines

Suspected poisoning? Read the article on pyrantel safety  in this site.

Never use on cats products approved only for use on dogs, and vice-versa.

You may be interested in the following articles in this site dealing with the general safety of veterinary products:


Risk of resistance development? YES, but rather low in Ancylostoma caninum.
There are reports on resistance of Ancylostoma spp to pyrantel in dogs and horses, but so far it does not seem to be widespread.

 Alternatives to prevent resistance through product rotation:

There are no reports on resistance of of tapeworms to praziquantel.

Learn more about resistance and how it develops.


Are the active ingredients of this product ORIGINAL* or GENERICS**?

  • Pyrantel: GENERIC (introduced in the 1960s)

*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, in many countries. This product contains itself generic pyrantel

Click here to learn more about GENERIC vs. ORIGINAL drugs.


happy jack liqui-vict 2x is a dog wormer from HAPPY JACK with generic pyrantel, effective against roundworms and hookworms.

Pyrantel is a broad-spectrum nematicide effective against important dog worms such as the roundworm Toxocara canis and the hookworms Ancylostoma caninum, Ancylostoma braziliense and Uncinaria stenocephala. Pyrantel has no effect on tapeworms. It is a well-tolerated anthelmintic belonging to the chemical class of the tetrahydropyrimidines.

Pyrantel is a narrow-spectrum anthelmintic belonging to the chemical class of the tetrahydropyrimidines that was introduced in the 1960s (by PFIZER → ZOETIS). It  is effective against roundworms and a few tapeworms (depending on the dose) in the gut, but not against those in other organs (e.g. the lungs, the skin, etc). It controls important dog worms such as the roundworms Toxocara canis and Toxascaris leonina, the hookworms Ancylostoma caninum and Uncinaria stenocephala. It is used a lot in pets and horses but rarely in livestock. There are dozens of products for pets with generic pyrantel. It is not used in agriculture.

Pyrantel as well as benzimidazoles (e.g.fenbendazole, febantel, albendazole, mebendazole, etc.) has no residual effect, i.e. it acts against the worms during a few hours after administration but is quickly metabolized and excreted. For this reason treatment must often be repeated for certain indications. This is in contrast with wormers containing macrocyclic lactones (e.g. milbemycin oxime, selamectin) that ensure efficacy against numerous roundworms during weeks after a single treatment.

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. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.