Your pup isn't the only four-legged creature vulnerable to roundworm. A host of farm animals, including sheep, goats and poultry also host this nematode. Levamisole is a useful way to combat this intestinal parasite in many animals, however, it's no longer used to treat roundworm in dogs in the United States. Other countries still use an oral formulation of levamisole to treat Toxocara canis, or roundworm infection.
Not the Treatment of Choice for Dogs
The Merck Veterinary Manual for Veterinary Professionals states levamisole is highly effective in combating roundworm in pigs, sheep, goats and cattle. Though the drug doesn't kill roundworm eggs, it acts on the nematode's nervous system, disabling it so it's passed through the animal's system. If your pup has roundworms, the veterinarian will likely prescribe a different medication. According to the Companion Animal Parasite Council, moxidectin, fenbendazole, pyrantel pamoate and milbemycin oxime are approved for treating Toxocara canis in the U.S.