Mebendazole is a highly effective, broad-spectrum antihelmintic indicated for the treatment of nematode infestations, including roundworm, hookworm, whipworm, threadworm, pinworm, and the intestinal form of trichinosis prior to its spread into the tissues beyond the digestive tract. Other drugs are used to treat worm infections outside the digestive tract, as mebendazole is poorly absorbed into the bloodstream. Mebendazole is used alone in those with mild to moderate infestations. It kills parasites relatively slowly, and in those with very heavy infestations, it can cause some parasites to migrate out of the digestive system, leading to appendicitis, bile duct problems, or intestinal perforation. To avoid this, heavily infested patients may be treated with piperazine, either before or instead of mebendazole. Piperazine paralyses the parasites, causing them to pass in the feces. It is also used rarely in the treatment of cystic echinococcosis, also known as hydatid disease. Evidence for effectiveness for this disease, however, is poor. Mebendazole and other benzimidazole antithelmetics are active against both larval and adult stages of nematodes, and in the cases of roundworm and whipworm, kill the eggs, as well. Paralysis and death of the parasites occurs slowly, and elimination in the feces may require several days.
Special populations
Mebendazole is pregnancy category C, which means it has been shown to cause ill effects in pregnancy in animal models, and no adequate studies of its effects in human pregnancy have been conducted. Whether it can be passed by breastfeeding is unknown.
Mebendazole works by selectively inhibiting the synthesis of microtubules via binding to colchicine binding site of β-tubulin, thereby blocking polymerisation of tubulin dimers in intestinal cells of parasites. Disruption of cytoplasmic microtubules leads to blocking the uptake of glucose and other nutrients, resulting in the gradual immobilization and eventual death of the helminths. Poor absorption in digestive tract makes mebendazole an efficient drug for treating intestinal parasitic infections with limited adverse effects. However mebendazole has impact on mammalian cells mostly by inhibiting polymeration of tubulin dimers, thereby disrupting essential microtubule structures such as mitotic spindle. Disassembly of mitotic spindle then leads to apoptosis mediated via dephosphorylation of Bcl-2 which allows pro-apoptotic protein Bax to dimerize and innitiate programmed cell death.
Society and culture
Availability
Mebendazole is available as a generic medication. Mebendazole is distributed in international markets by Johnson and Johnson and a number of generic manufacturers.
Cost
In the United States a single dose was about USD 18.00 in 2015. In 2016 the price increased to USD 440.00 per dose in the U.S. as Amedra Pharmaceuticals acquired the rights from Teva in 2013. In 2010, Amedra also bought the U.S. marketing rights to the only other interchangeable anti-parasitic medication, albendazole, from GSK. The result of these acquisitions created a monopoly on these medications and the price increased dramatically. In 2015 Amedra Pharmaceuticals became a subsidiary of Amneal Pharmaceuticals. In Australia and the UK it costs about USD 5.00 per dose.
Research
Several studies show mebendazole exhibits potent antitumor properties. MBZ significantly inhibited cancer cell growth, migration, and metastatic formation of adrenocortical carcinoma, both in vitro and in vivo. Treatment of lung cancercell lines with MBZ caused mitotic arrest, followed by apoptotic cell death with the feature of caspase activation and cytochrome c release. MBZ induced a dose- and time-dependent apoptotic response in human lungcancer cell lines, and apoptosis via Bcl-2 inactivation in chemoresistant melanoma cells. The anti-cancer effect of mebendazole comes from preclinical studies and case reports.
