Fenbendazole is a safe broad-spectrum antiparasitic that destroys parasites by binding to tubulin, which is part of the cytoskeleton of the cell. In addition, fenbendazole interferes with the formation of microtubules that are needed for a parasite to move around the body of the host animal. Consequently, fenbendazole causes the parasite to break apart and die. It is commonly used as a dewormer in cats and dogs, under the brand name Panacur. Fenbendazole can also be used to treat some forms of liver disease in horses.
It is also used to kill parasites that cause gastrointestinal problems in dogs and cats, including ringworm, hookworms, whipworms, and tapeworms. It is an oral medication, and is available as capsules or suspension. It is typically given to pets under a veterinarian’s care and prescribed by the veterinarian. This is sometimes referred to as extra-label use or off-label use, because it’s a use that isn’t specifically described on the medication’s label. The veterinarian may recommend this drug for an animal’s specific medical condition or circumstance, but the use isn’t described on the label.
The veterinarian may prescribe fenbendazole as three daily injections of 50 mg/kg/day or in the diet, depending on the health status of the pet and the underlying issue. Veterinary offices often keep this medication in stock and may also have it compounded into a paste for easier administration. The compounding pharmacy usually adds a thickener to the drug, such as guar gum or cellulose. This is to ensure that the medication can be easily injected into the pet’s muscle or tissue. The pharmacy will also include a plastic tip to help inject the medication properly.
When used at regular doses, fenbendazole is well tolerated in most pets. Some common side effects include mild diarrhea or vomiting. In very rare cases, a pet may have an allergic reaction to the drug, and signs of this should be monitored carefully. If a pet has a serious allergic reaction, such as facial swelling, hives, or shock, seek immediate veterinary attention.
The effect of three daily fenbendazole injections on the growth and radiation response of EMT6 tumors in BALB/c mice was examined in two separate experiments. Mice were stratified by tumor volume and randomly assigned to receive a placebo or three daily fenbendazole treatments. Tumor volume was measured at three weekly intervals, and the time needed for the tumors to grow to four times their initial size was calculated. No significant difference was observed in the growth rate of unirradiated or irradiated tumors treated with fenbendazole. Radiosensitivity of fenbendazole-treated and control tumors was also compared by superimposing the survival curves on each other and performing isobologram analyses. The results indicate that fenbendazole did not affect the radiation response of aerobic or hypoxic tumors. fenbendazole capsules
