When it comes to cancer treatment, doctors and patients are always on the lookout for new avenues. Two medicines have come into the spotlight recently – Fenbendazole and Mebendazole. These medicines were initially developed to treat parasites in both animals and humans. However, now the focus is on exploring the possibility of using these medicines to treat cancer. Which one should you choose between the two, Fenbendazole or Mebendazole?
This guide will provide you with the necessary information on the difference between the two.
What Are Fenbendazole and Mebendazole?
Fenbendazole is a benzimidazole anthelmintic used to treat parasitic infections in animals. It may be known under different brand names, such as Panacur or Safe-Guard. As Fenbendazole has not yet been approved by the FDA or the EMA, its pharmacokinetics and safety profile in humans have not been extensively documented.
Key facts about Fenbendazole:
- Used to deworm dogs, cats, horses, and livestock
- Not approved for human use by the FDA
- Safety in humans is still unknown
Mebendazole, a well-known antihelminthic drug widely used in clinical practice, exhibits anticancer properties that have been characterized in numerous preclinical studies across a range of cancer types. Unlike fenbendazole, mebendazole is clinically used for human treatment.
Key facts about Mebendazole:
- FDA-approved for parasites in the human population
- Mebendazole is available by prescription only
- Mebendazole is relatively inexpensive, especially when compared to many common drugs that fight cancer.
- It has been tested in some clinical trials for cancer
How These Drugs Work Against Cancer
Both Fenbendazole and Mebendazole belong to the same benzimidazole family. Both drugs work in the same way to fight cancer cells.
Shared Cancer-Fighting Mechanisms
Microtubule Disruption: Fenbendazole is a mild disruptor of the microtubule network. This disrupts cancer cell lines by modulating multiple cellular pathways. Mebendazole functions as an anti-tubulin agent. This demonstrates the inhibition of tubulin polymerization.
Blocking the Energy Source: The anti-cancer properties of fenbendazole are thought to result from increased p53 activation. This inhibits the activity of the GLUT1 transporter and the enzyme hexokinase. This reduces the glucose uptake by the cancer cell. This demonstrates the capacity of the drugs to “starve the cancer cell of its energy source.”
Promoting Cell Death: Both drugs are capable of inducing cell death through the body’s natural mechanism of apoptosis.
Unique Features
Fenbendazole: It has several other mechanisms that contribute to its anticancer properties, particularly its effects on energy metabolism in cancer cells. It is a microtubule destabilizing agent, a proteasomal inhibitor, and a glucose metabolism inhibitor.
Mebendazole: It blocks distant organ metastasis partly by reducing ITGβ4 expression and cancer stemness, which means that it may stop cancer from spreading throughout the body.
Research Evidence
Fenbendazole Research
Most studies on Fenbendazole have been conducted in test tubes or on animals, not on humans.
Laboratory Studies: A flow cytometry study showed that fenbendazole induced apoptosis and G2/M cell cycle arrest in colorectal cancer cells.
Animal Studies: The natural form of FZ was active against EOC cells in vitro but was ineffective when administered orally or IP due to its water-insolubility. This is a major issue with the drug since it does not dissolve well in water.
Human Case Reports: Table IV discusses the results of four case reports where the tumor size was reduced due to the administration of fenbendazole, but also discusses the results of two cases where the patient experienced drug-induced hepatic dysfunction.
Mebendazole Research
Mebendazole has more human studies compared to Fenbendazole.
Brain Cancer: An in vivo study demonstrated that oral administration of MBZ increased survival time by up to 63% in syngeneic and orthotopic xenograft mouse glioma models.
Breast Cancer: We demonstrate that treating cells with MBZ resulted in a dramatic decrease in integrin β4 expression in vitro and in cancer cells isolated from tumor-bearing mice after MBZ treatment.
Colorectal Cancer: Mebendazole was found to increase tumor response to treatment, resulting in a significant improvement of overall response rate after 12 weeks of treatment in a human clinical trial.
Safety Concerns
In this section, let us discuss the safety concerns and side effects of both drugs.
Fenbendazole Safety Concerns
Not Approved for Humans: The first concern is that the FDA or EMA does not approve the drug for human use. This means that without such approval, it cannot be guaranteed that the drug is safe, effective, and correctly dosed for human use.
Liver Problems: The second concern is two instances where patients were subjected to drug-related hepatic problems. In both cases, patients’ liver function improved rapidly after withdrawal of fenbendazole.
Absorption Problems: Although Fenbendazole shows promising anti-cancer properties, its poor water solubility has limited its therapeutic potential.
Potential Risks: Fenbendazole may act as a tumor promoter when given after certain tumor initiators in some cases.
Mebendazole Safety Concerns
FDA Approved: Yes. The drug has been tested and approved for human use for many years to treat parasites.
Known Side Effects: Mebendazole may cause abdominal pain, headache, diarrhea, fatigue, and anemia.
Blood-Brain Barrier: The lipophilic nature and low molecular weight of MBZ enable it to cross the blood-brain barrier and treat brain cancers.
Drug Interactions: The drug interacts with the combination of nitroglycerin and metformin or the combination of disulfiram and metformin.
Current Clinical Trials
Fenbendazole Trials
Currently, little is known about clinical trials underway to test the efficacy of using fenbendazole for cancer treatment.
Mebendazole Trials
There are many clinical trials underway for mebendazole to treat cancer:
- Currently recruiting for the study, with an estimated completion date of April 2025, for a brain cancer study
- Studies for colorectal cancer have been successful
- Breast cancer is also showing positive results
Conclusion
Mebendazole and Fenbendazole are both drugs used to treat worm infections. Some studies have examined the possible effects of Mebendazole and Fenbendazole on cancer cells. However, no strong evidence is available to confirm that either of the drugs can be used to treat cancer.
Cancer patients should only be treated with the options recommended by their doctors. Scientific studies are always open to possibilities. Therefore, Mebendazole and Fenbendazole can only be used for their medical purposes.