Mebendazole binds to the colchicine-sensitive site of tubulin, inhibiting its polymerization into microtubules. This binding disrupts the cytoplasmic microtubules in the intestinal cells of the helminth, impairing the uptake of glucose. The depletion of glycogen stores in the parasite leads to a decrease in ATP production, causing degenerative changes in the endoplasmic reticulum and mitochondria, which ultimately results in the death of the worm. In addition, mebendazole has been reported to inhibit the Hedgehog signaling pathway and stabilize HIF-1α.

With an IC50 value of 0.24 μM, mebendazole (1 nM-0.1 mM; 72 h) inhibits GL261 tumor neural cells [1]. 0.1 μM and 1 μM mebendazole for 24 hours causes 060919 pleomorphic astrocyte disruption. Mebendazole (10 nM–10 μM; 48 h) suppresses microtubule polymerization and microtubule structure in tumor (GBM) cells, inhibits Hh signaling, and reduces downstream Hh protein expression. It also regulates Hh protein expression by lowering Gli1 in tumor tissues [1]. Gli1 expression is inhibited by metronidazole, with an IC50 value of 516 nM[2]. Human medulloblastoma tumor cells with constitutive Hh activation exhibit reduced expression and blocked primary cilia development when exposed to mebendazole (10 nM-10 μM; 48 h). Additive suppression of normal Hh signaling is achieved when mebendazole and vismodegib are combined [2]. In a therapeutic environment, mebendazole has been demonstrated to be successful in treating severe cases of CNS echinococcosis. fluorescent imaging [1]
In vitro, mebendazole has demonstrated activity against a range of cancer cell lines. It has been shown to induce a dose- and time-dependent apoptotic response in human lung cancer cell lines. This compound arrests cells at the G2-M phase before the onset of apoptosis. Mebendazole also exhibits inhibitory effects against glioblastoma multiforme (GBM) and has been studied for its potential to abrogate oxidative neuronal death. Its broad-spectrum activity in vitro makes it a candidate for drug repurposing.

Mebendazole (50 mg/kg; oral; once daily for the first 20 days, five days a week, two days off; 45 days) was administered to both the human pleomorphic blastoma (GBM) xenograft 060919 and the syngeneic GL261 mouse model.
In vivo, mebendazole has been effective in treating a wide range of parasitic infections in animals and humans. Studies have also investigated its anticancer activity in mouse xenograft models, where it has shown promise in reducing tumor growth. The compound's ability to penetrate the blood-brain barrier has also made it a subject of research for brain cancers.

In vitro enzyme or receptor binding (non-cell) assays for mebendazole involve studying its interaction with tubulin. In these assays, purified tubulin is incubated with the compound in the presence of a substrate. The inhibition of tubulin polymerization is measured spectrophotometrically by monitoring the increase in turbidity that accompanies microtubule formation. Additionally, competition binding assays using [³H]colchicine can be performed to determine the affinity of mebendazole for the colchicine-binding site on tubulin.

Immunofluorescence [1]
Cell Types: Glioblastoma multiforme (GBM) 060919 Cell
Tested Concentrations: 1 μM
Incubation Duration: 24 hrs (hours)
Experimental Results: The microtubule structure is destroyed. System penetration characteristics [3].

---

Immunofluorescence [2]
Cell Types: DAOY and hTERT-RPE1 Cell
Tested Concentrations: 0, 0.1, 0.5, 0.75 and 1 μM
Incubation Duration: 12 hrs (hours)
Experimental Results: GLI1 protein levels diminished and caspase-3 protein levels increased cleavage.
In vitro cell-based assays for mebendazole are performed using both parasite and cancer cell lines. Parasite assays involve culturing helminths (e.g., C. elegans) in the presence of the compound and assessing their motility and viability. For cancer research, various human cancer cell lines (e.g., lung, breast, glioblastoma) are treated with mebendazole, and cell viability, proliferation, and apoptosis are measured using MTT assays, flow cytometry, and Western blotting for markers like caspases.

Animal/Disease Models: C57BL/6 mice (5-6 weeks old) implanted with GL261 glioma cells and 060919 human glioblastoma multiforme (GBM) [1]
Doses: 50 mg/kg; Inhibition in mouse model Intracranial tumor growth [1]. Use 50% (v/v) sesame oil and PBS[2]
Route of Administration: po (oral gavage); starting 5 days after tumor implantation, daily dose of 50 mg/kg for the first 20 days of treatment, then changing to 50 mg/kg, Lasts 5 days, with 2 days off per week.
Experimental Results: In the syngeneic GL261 mouse model, mean survival increased to 49 days compared with 30 days in controls. Mean survival was extended to 65 days compared with 48 days of controls in the 060919 human glioblastoma multiforme (GBM) xenograft mouse model.
In vivo animal experiments for mebendazole involve both parasitic infection models and cancer xenograft models. For anthelmintic studies, animals infected with specific parasites (e.g., Trichinella spiralis) are treated with the compound, and the reduction in parasite burden is assessed by counting adult worms or larvae in tissues post-mortem. In cancer research, mice bearing subcutaneous tumors are treated with mebendazole, and tumor volume is measured over time.

Absorption, Distribution and Excretion
This product is poorly absorbed in the gastrointestinal tract (approximately 5%–10%). Fatty foods can increase absorption. In the human body, approximately 2% of mebendazole is excreted in the urine, and the remainder is excreted in the feces as the unchanged drug or its major metabolite. Excretion: Feces: Approximately 95% is excreted in the feces as the unchanged drug or its major metabolite (2-amino derivative). Kidneys: Approximately 2%–5% is excreted in the urine as the unchanged drug or its major metabolite. Peak serum concentration: After 3 days of twice-daily administration of 100 mg: Mebendazole: Not exceeding 0.03 μg/mL. 2-Amino metabolite: Not exceeding 0.09 μg/mL. It has been reported that serum concentrations can reach 0.5 μg/mL during long-term high-dose treatment. Time to peak serum concentration: 2 to 5 hours (range: 0.5 to 7 hours). Mebendazole is highly bound to plasma proteins. It is currently unclear whether mebendazole is excreted into breast milk. For more complete data on the absorption, distribution, and excretion of mebendazole (11 items total), please visit the HSDB record page. Metabolites/Metabolic Substances Primarily metabolized in the liver. The major metabolite is 2-amino-5-benzoylbenzimidazole, but it is also metabolized to inactive hydroxy and hydroxyamino metabolites. None of the metabolites have anthelmintic activity. Primarily metabolized in the liver; metabolized to inactive amino, hydroxy, and hydroxyamino metabolites; the major metabolite is 2-amino-5-benzoylbenzimidazole. Although the exact metabolic pathway of mebendazole is not fully determined, the drug is decarboxylated to 2-amino-5(6)-benzimidazolylphenyl ketone; this metabolite has no anthelmintic activity. Mebendazole…is widely metabolized. The two main metabolites, 5-(α-5-hydroxybenzyl)-2-benzimidazole carbamate and 2-amino-5-benzoylbenzimidazole, have lower clearance rates than mebendazole itself. Mebendazole, rather than its metabolites, appears to be the active drug form. Conjugates of mebendazole and its metabolites have been found in bile, but almost no unmetabolized mebendazole is found in urine.
Biological Half-Life
The biological half-life in patients with normal liver function is 2.5 to 5.5 hours (range 2.5 to 9 hours). The biological half-life in patients with impaired liver function (cholestasis) is approximately 35 hours.
Normal liver function: 2.5 to 5.5 hours (range: 2.5 to 9 hours). Impaired liver function (cholestasis): approximately 35 hours.
The elimination half-life of mebendazole has been reported to be approximately 2.8–9 hours.
Pharmacokinetic (PK) properties of mebendazole include poor and variable oral absorption due to its low aqueous solubility. The drug is extensively metabolized in the liver and has a short half-life. Its bioavailability can be increased when taken with a high-fat meal. The compound is distributed throughout the body but has poor penetration into the central nervous system. Mebendazole is primarily excreted in the feces.

Hepatotoxicity
Mebendazole typically does not cause elevated serum enzymes at conventional doses, although treatment duration is usually short and reports of enzyme elevation are rare. High-dose treatment (rarely used now due to the advent of albendazole) can lead to elevated serum transaminase levels (2 to 10 times the normal value), but is generally well tolerated. Rare reports of acute liver injury caused by mebendazole exist, especially with repeated or high-dose administration. Onset usually occurs within days of starting or restarting treatment, presenting as fever and malaise. The pattern of elevated serum enzymes is usually hepatocellular, and jaundice is uncommon. These abnormalities usually resolve rapidly after discontinuation of the drug. Typical manifestations of allergic reactions (rash, fever, and eosinophilia) and liver biopsy may show granulomas.
Probability score: D (Long-term treatment may lead to clinically significant liver injury).
Use during pregnancy and lactation

◉ Overview of use during lactation
Mebendazole is rarely excreted into breast milk and is poorly absorbed orally. Reports on mebendazole use during lactation show no adverse reactions in breastfed infants. A few cases have reported reduced milk production after mebendazole use, but there is no conclusive evidence that this is caused by the drug. No special attention is required.
◉ Effects on Breastfed Infants
A case series reported on 45 lactating women who took mebendazole at doses ranging from 100 mg once daily to 200 mg twice daily for 3 days. Approximately half of the infants received 100 mg, repeated once after 7 to 14 days. 33 infants were exclusively breastfed, aged 1 to 30 weeks. Of the 12 partially breastfed infants, 8 were over 20 weeks old. None of the mothers reported any adverse reactions.
In the Democratic Republic of Congo, researchers followed up on 33 infants (the extent of breastfeeding was not specified) breastfed by mothers hospitalized and taking nifurolimus. Thirty mothers completed a course of 30 doses of oral nifurolimus (15 mg/kg/day), and all mothers received 14 doses of intravenous efornithine (400 mg/kg/day) for 7 days to treat human African trypanosomiasis (sleeping sickness). Seventeen lactating mothers also received mebendazole. No serious adverse events were reported in any of the breastfed infants.
◉ Effects on lactation and breast milk
A lactating mother 13 weeks postpartum was taking metronidazole 250 mg three times daily. Milk production appeared unaffected. On the eighth day of treatment, she expelled a roundworm. Metronidazole was discontinued, and mebendazole was started at 100 mg twice daily. The patient felt “stressed” for several days after expelling the roundworm. On the second day of mebendazole treatment, milk production decreased significantly, and she began adding formula. By the seventh day, milk production had completely stopped. The authors suggest that mebendazole may be the cause of decreased milk production, but provide no further evidence beyond the time frame. Four patients received mebendazole at 100 mg twice daily for three days, starting on postpartum day. Two were infected with Enterobius, one with Ascaris, and one with Ancyclostomia. All subjects successfully breastfed. One author reported that information obtained through private communication with the manufacturer indicated no milk suppression was observed in lactating mothers after a single oral dose of 100 mg mebendazole (postpartum time not specified). In a case series study, 45 lactating mothers received mebendazole at doses ranging from 100 mg once daily to 200 mg twice daily for three days. One mother reported a slight decrease in milk production. Protein Binding Rate: 90-95% Drug Interactions: Preliminary evidence suggests that cimetidine inhibits the metabolism of mebendazole and may lead to elevated plasma drug concentrations. Limited data indicate that both carbamazepine and phenytoin sodium may enhance the metabolism of mebendazole, possibly by inducing hepatic microsomal enzymes, resulting in decreased plasma mebendazole concentrations. This interaction is unlikely to be clinically significant in treated patients. Mebendazole is used to treat intestinal worm infections; however, in patients receiving mebendazole for extraintestinal infections (e.g., echinococcosis), concomitant use of carbamazepine or phenytoin sodium may affect its efficacy. Until more data are available, other anticonvulsants (e.g., valproic acid) should be considered for patients receiving mebendazole for extraintestinal infections. Non-human Toxicity Values: Oral LD50 in sheep > 80 mg/kg
Toxicology (toxicology) data for mebendazole indicate that it is generally well-tolerated in humans when used for short-term anthelmintic therapy. Common side effects include gastrointestinal disturbances such as abdominal pain and diarrhea. Rare but serious side effects include bone marrow suppression and hepatotoxicity. The drug is contraindicated in pregnancy and in patients with liver disease.

[1]. Bai RY, et al. Antiparasitic mebendazole shows survival benefit in 2 preclinical models of glioblastoma multiforme. Neuro Oncol. 2011 Sep;13(9):974-82.
[2]. Larsen AR, et al. Repurposing the antihelmintic mebendazole as a hedgehog inhibitor. Mol Cancer Ther. 2015 Jan;14(1):3-13.
[3]. Erdinçler P, et al. The role of mebendazole in the surgical treatment of central nervous system hydatid disease. Br J Neurosurg. 1997 Apr;11(2):116-20.

Therapeutic Uses
MeSH Title: Antinematode Drugs
Mebendazole is indicated for the treatment of whipworm infection caused by Trichuris trichiura. /Included on US product label/
Mebendazole is indicated for the treatment of various intestinal nematode infections. /Included on US product label/
Mebendazole is indicated for the treatment of pinworm infection caused by Enterobius vermicularis. /Included on US product label/
For more complete data on the therapeutic uses of mebendazole (19 in total), please visit the HSDB record page.

---

Drug Warnings
During prolonged use of mebendazole, organ system function (including hematopoietic and liver function) should be evaluated regularly. Other rare adverse reactions in patients treated with mebendazole include alopecia, rash, pruritus, urticaria, angioedema, flushing, hiccups, cough, fatigue, somnolence, chills, hypotension, seizures, transient abnormalities in liver function tests (e.g., elevated serum transaminases, alkaline phosphatase, and/or bilirubin levels), hepatitis, elevated blood urea nitrogen, decreased hemoglobin levels and/or hematocrit, leukopenia, thrombocytopenia, eosinophilia, and hyperurea nitrogenosis. Urine columnar urination has also been reported. Ascaris lumbricoides migration via the mouth and nose has also been reported. Myelosuppression, manifested as neutropenia (including agranulocytosis) and/or thrombocytopenia, has been reported in patients receiving high doses (e.g., 30–50 mg/kg daily) of mebendazole for extraintestinal infections; although myelosuppression is usually reversible upon discontinuation of the drug, deaths are rare. At the commonly recommended dose (i.e., 100-200 mg daily), mebendazole appears to cause very few side effects. Side effects appear to be more common at higher doses (e.g., doses used to treat extraintestinal infections such as echinococcosis), and in some cases may be related to drug-induced parasite-killing effects. Transient diarrhea and abdominal pain have been occasionally reported during mebendazole treatment, but are usually associated with large amounts of infection and worm expulsion. Nausea, vomiting, headache, tinnitus, numbness, and dizziness have been occasionally reported during mebendazole treatment. Fever has occurred in some patients, especially those receiving high doses for extraintestinal infections. For more complete data on drug warnings for mebendazole (9 of 9), please visit the HSDB record page.

---

Pharmacodynamics
Mebendazole is a (synthetic) broad-spectrum anthelmintic. The primary mechanism of action of mebendazole is through the inhibition of tubulin polymerization, leading to the loss of cytoplasmic microtubules.
Other information: Mebendazole is marketed under brand names such as Vermox and Emverm. It is on the World Health Organization's List of Essential Medicines. The drug is being repurposed and studied in clinical trials for various cancers due to its ability to inhibit tubulin polymerization and its potential to cross the blood-brain barrier.

C16H13N3O3

295.3

295.095

31431-39-7

Mebendazole-d3;1173021-87-8

4030

Off-white amorphous powder
Crystals from acetic acid and methanol

1.4±0.1 g/cm3

288.5°C

1.703

2.83

2

4

4

22

423

0

O=C(OC)NC1=NC2=CC=C(C(C3=CC=CC=C3)=O)C=C2N1

OPXLLQIJSORQAM-UHFFFAOYSA-N InChi Code

InChI=1S/C16H13N3O3/c1-22-16(21)19-15-17-12-8-7-11(9-13(12)18-15)14(20)10-5-3-2-4-6-10/h2-9H,1H3,(H2,17,18,19,21)

methyl N-(6-benzoyl-1H-benzimidazol-2-yl)carbamate

Mebendazole Vermox Telmin Pantelmin Mebenvet Telmin Vermicol Vermidil Vermin Vermox Wormkuur

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~4.17 mg/mL (~14.12 mM)
H2O : < 0.1 mg/mL

Solubility in Formulation 1: ≥ 0.42 mg/mL (1.42 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 4.2 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 0.42 mg/mL (1.42 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 4.2 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 0.42 mg/mL (1.42 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 4.2 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)