Fenben lab fenbendazol is an animal anthelmintic in the broad spectrum benzimidazole carbamate family of drugs (I call them BZ), with long track record of safety and efficacy in veterinary use. It is effective against giardia, roundworms (including Ascaris and hookworm) and whipworms, the tapeworm genus Taenia (but not Dipylidium caninum, the common dog tapeworm), pinworms, aelurostrongylus and strongyloides. It is also used in freshwater shrimp tanks to treat hydra and planaria, and for capillaria in pet poultry during molting.
Fenbendazole belongs to a class of drugs known as benzimidazoles, or bZs for short. The bZs are broad-spectrum anthelmintic medications that have been safely used for decades in both humans and animals, primarily as parasitic worm treatments. There are several members of this family, including mebendazole (MBZ), albendazole (ABZ), oxibendazole (OBZ) and flubendazole (FLU). They all work by disrupting the microtubules inside cells, which are like little ropes that hold things together in a cell. When a cancer cell can’t form its microtubules, it cannot grow or reproduce as fast as normal cells, and dies. Unlike chemotherapy, which destroys all cells in the body, bZs only target abnormal cells, such as cancer cells.
Despite its effectiveness as an animal anthelmintic, bZs don’t have much effect on human tumors on their own. However, when paired with vitamins, they seem to have considerable anti-cancer effects. Specifically, the bZs interfere with sugar uptake in cancer cells, which can starve them of their primary fuel source. They also boost the production of a cancer-killing gene called p53.
In a recent study, a group of mice were implanted with lymphoma cells and treated with either fenbendazole or a vitamin-rich diet. When compared to control groups, the fenbendazole-vitamin group had a significantly reduced tumor size. While further research and substantial evidence is needed to confirm these results, the repurposed use of fenbendazole for cancer shows promise.