Are ivermectin and mebendazole effective as anticancer treatments?

Ivermectin and Mebendazole as Anticancer Treatments

Ivermectin and mebendazole do not have established anticancer properties for clinical use, and current medical guidelines do not recommend these antiparasitic medications for cancer treatment.

Current Evidence Status

Ivermectin

• Ivermectin is primarily approved and recommended for treating parasitic infections including strongyloidiasis, onchocerciasis, and other helminth infections 1.
• While preclinical research shows potential anticancer effects in laboratory settings, these studies have been conducted at concentrations that may not be clinically feasible or safe in humans 2.
• Some in vitro studies have demonstrated that ivermectin can:
  • Inhibit tumor metastasis by regulating the Wnt/β-catenin/integrin β1/FAK signaling pathway 3
  • Induce cell cycle arrest in breast and ovarian cancer cell lines 2
  • Inhibit bladder cancer cell growth and induce oxidative stress and DNA damage 4

Mebendazole

• Mebendazole is recommended for treating various parasitic infections including ascariasis, hookworm infections, trichuriasis, and enterobiasis 1.
• Like ivermectin, mebendazole has shown some anticancer properties in preclinical studies but lacks robust clinical evidence 5.
• Both drugs work by blocking microtubule systems, which can inhibit glucose uptake and transport in both parasites and mammalian cells, potentially leading to cell death 5.

Clinical Application Limitations

Safety Concerns

• When used for prolonged periods (>14-28 days), these medications may cause liver toxicity and other adverse reactions 5.
• For anticancer effects, higher doses might be required, which could increase the risk of side effects including neutropenia due to myelosuppression 5.

Evidence Quality

• Current evidence is primarily limited to:
  • In vitro laboratory studies
  • Animal models
  • Very limited case reports
  • Small observational studies

Real-world Usage

• A study in Ecuador found that 19% of cancer patients were taking ivermectin as an alternative therapy alongside conventional treatments like chemotherapy, radiotherapy, or immunotherapy 6.
• However, medical specialists do not recommend these treatments due to lack of authorization and insufficient scientific evidence for human application in cancer 6.

Recommendations for Clinical Practice

1. Do not prescribe ivermectin or mebendazole for cancer treatment outside of clinical trials.
2. Adhere to established cancer treatment guidelines that recommend evidence-based therapies specific to cancer type, stage, and patient characteristics.
3. Consider clinical trial participation for patients interested in investigational therapies.
4. When encountering patients self-medicating with these drugs:
   • Assess for potential drug interactions with conventional cancer treatments
   • Monitor for adverse effects, particularly with prolonged use
   • Provide education about the limited evidence supporting anticancer effects

Future Directions

The repositioning of antiparasitic drugs for cancer treatment remains an active area of research. Both ivermectin and mebendazole warrant further investigation through:

• Properly designed clinical trials
• Determination of optimal dosing that balances efficacy and safety
• Identification of specific cancer types most likely to respond

Until such evidence becomes available, standard cancer treatments following established guidelines should remain the mainstay of therapy.