Albendazole belongs to the family of nematocidal agents we call benzimidazoles. Benzimidazoles are said to be effective against roundworms, whipworms, and hookworms in most species and have some activity against tapeworms. Albendazole is also effective against common protozoans.1

Mechanism of Action of Albendazole

The molecular mode of action of all benzimidazoles, including albendazole, consists of binding to tubulin, a structural protein of microtubules. The drugs bind to nematode tubulin, preventing its polymerization during microtubule assembly and thus disrupting cell division.1



These microtubules are important organelles involved in the motility, the division and the secretion processes of cells in all living organisms. In the worms, the blocking of microtubules perturbs the uptake of glucose, which eventually empties the glycogen reserves. This blocks the whole energy management mechanism of the worms that are paralyzed and die or are expelled.

Since cell division is also disturbed, worm egg production and development is also blocked by benzimidazoles, i.e. most of them also have an ovicidal effect.

Albendazole also inhibits a helminth-specific fumarate reductase, an enzyme involved in the energy management of the worm cells as well.2

From an independent site, below is the SAFETY SUMMARY for Albendazole. With regards to, it is not financed by the Animal Health industry or by any other private or public institution. It sells nothing. It just delivers solid information free of charge. Hoping that when leaving the site, visitors will know a little bit more about parasites and their control than when they arrived.

The site targets both pet owners as well as animal health professionals (farmers, producers, breeders, veterinarians, zootechnicians, sales representatives and distributors of veterinary parasiticides, nurses, etc.) that are confronted with practical problems regarding parasites and need information to sort them out.

Albendazole Safety Summary for Veterinary Use

For the acute toxicity and tolerance levels of albendazole, recorded LD50 acute, rats is p.o. 1.55 to 3.25 g/kg. The safety margins for dogs, NEL (no effect level) in 1-year chronic toxicity studies at 0.35 mg/kg/day p.o. was recorded.

The following has been listed as toxic symptoms caused by Albendazole poisoning:

  • Liver, testicles, and GIT are most affected organs after exposure to high albendazole doses.
  • Overdosing may also produce lethargy, loss of appetite, intestinal cramps, nausea, diarrhea, and vomiting.
  • Other reported symptoms include dizziness, convulsions, and sleeplessness.

Albendazole Side Effects, Adverse Drug Reactions (ADRs) and Warnings

  • In pregnant bitches, albendazole treatment can cause the reduced weight of puppies at birth and palatoschisis (cleft palate).
  • Albendazole should not be administered to animals suffering from hepatic disorders.

 Just like any drug, albendazole’s efficacy is achieved when properly used and side effects can be observed when recommended use is not followed. So for products to be maximized, we say -follow the recommendations and read the labels.


1 Clinical Pharmacology, Cynthia Webster, 2001 (Teton New Media)

Published by: plaridel
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