Fenbendazole is a long-established antiparasitic (anthelmintic) agent used mainly in animals. It belongs to a group of compounds called benzimidazoles, developed in the 1970s. In laboratories it is sometimes used as a tool for studying the interior of the cell, and in veterinary medicine it is valued for working against many parasites while being safe for the treated animal.
Which family of compounds it belongs to
Chemically, fenbendazole is related to several other antiparasitic drugs, among them albendazole, mebendazole and oxfendazole. The last of these is in fact the substance fenbendazole turns into inside the body.
How it works: it blocks the cell's “scaffolding”
Fenbendazole binds to a protein called β-tubulin and stops it assembling into what are known as microtubules. Microtubules are tiny tube-like structures that act as the cell's internal scaffolding and “railway tracks”: they transport substances, give the cell its shape and take part in its division.
Once fenbendazole blocks the formation of those tubes, several things start going wrong at once inside the parasite's cell: internal transport stops working, the parasite can no longer take up and process sugar (glucose) properly and so loses its energy source. As a result, it dies.
Why it harms the parasite and not the animal
The β-tubulin protein differs in small structural details between a parasite and a mammal. Because of this, fenbendazole grips the parasite's protein far more strongly than the host's. That is what explains its selective action on worms and its relative safety in the treated animal.
What happens to it in the body
Fenbendazole dissolves poorly in water, so the body absorbs it to a limited and variable degree. Once absorbed it is converted first into active oxfendazole and then into an inactive form that is excreted. The way this compound is processed differs markedly between animal species, which matters when planning experiments and preparing solutions in the laboratory.
What it works against (in animals)
In veterinary medicine fenbendazole is given against gastrointestinal and respiratory worms and certain other parasites in many species. That is its official, established and approved use.
Resistance — an interesting research topic
Because benzimidazoles were used so widely, some parasites have become resistant to them. This happens through small changes (mutations) in the gene for β-tubulin that make the drug bind it less well. It is a classic, well-studied example of how organisms become resistant to drugs.
Use as a research reagent
Thanks to its well-characterised mechanism, fenbendazole is sometimes used in the laboratory as a tool for studying microtubules and as a reference standard in chemical analysis. SWISS LAB supplies it as a reagent of defined purity, intended for laboratory work.
Sources
- Dogra N. et al. (2018), Fenbendazole acts as a moderate microtubule destabilizing agent…, Scientific Reports — nature.com/articles/s41598-018-30158-6
For in-vitro laboratory research only. It is not a human medicine and is not for treatment.