Why is mebendazole no longer available? A Pharmacological Review

October 14, 2025 •

3 min read

Over 1.5 billion people, or 24% of the world's population, are infected with soil-transmitted parasitic worms. Mebendazole has long been a frontline treatment for these infections. Given its effectiveness, many patients and practitioners are asking: why is mebendazole no longer available in its once-common forms?

Quick Summary

The antiparasitic drug mebendazole's availability has shifted, particularly in the US where the brand Vermox was discontinued for business reasons. The remaining brand, Emverm, has a high cost, making alternatives crucial.

Key Points

Vermox Discontinued: The common brand of mebendazole, Vermox, was discontinued in the U.S. for commercial reasons, not due to safety or efficacy issues.
High Cost of Emverm: The only mebendazole brand currently available in the U.S., Emverm, is very expensive because there is no generic competition.
Global Importance: Mebendazole remains a WHO Essential Medicine and is widely used in international public health programs to deworm children.
Mechanism of Action: Mebendazole works by blocking a worm's ability to absorb glucose, effectively starving it to death.
Prescription Alternative: Albendazole is an effective prescription alternative that is available as a more affordable generic and is often preferred for certain infections like hookworm.
OTC Alternative: For pinworms, pyrantel pamoate (e.g., Reese's Pinworm Medicine) is a low-cost, effective over-the-counter option.
Hygiene is Key: Medication should be combined with strict hygiene practices to prevent reinfection from worm eggs left on surfaces, clothing, and hands.

The Shifting Landscape of an Essential Medicine

Mebendazole is an anthelmintic (anti-worm) medication recognized by the World Health Organization (WHO) as an essential medicine for treating a variety of intestinal worm infections. It is used extensively in global public health initiatives, with millions of doses donated annually for mass deworming campaigns in high-risk regions. However, in the United States and some other developed nations, the availability and affordability of this drug have changed dramatically, leading to confusion among both patients and healthcare providers.

The Discontinuation of Vermox in the U.S.

For decades, mebendazole was widely known under the brand name Vermox. However, Vermox has been discontinued and is no longer commercially available in the United States. According to the U.S. Food and Drug Administration (FDA), this discontinuation was not due to issues with the drug's safety or efficacy. Instead, it was a business decision made by the manufacturer. Some reports from 2011 suggest the initial withdrawal was related to the drug's poor tissue penetration and the availability of albendazole.

While the generic form of mebendazole was once inexpensive, its reintroduction to the market came with a significant price increase. Currently, the only version of mebendazole on the market in the U.S. is a brand-name chewable tablet called Emverm. The lack of a generic alternative has allowed its price to soar, with a single tablet costing over $600 without insurance, and a full course of treatment for some infections costing thousands. This high cost has rendered it inaccessible for many patients, forcing them to seek other options.

How Mebendazole Works

Mebendazole belongs to a class of drugs called benzimidazoles. Its mechanism of action is targeted specifically at the parasites. By binding to beta-tubulin in worm cells, it disrupts microtubule formation, preventing glucose absorption and ultimately leading to the worm's death and expulsion. It is effective against common intestinal nematodes, and Emverm is approved for pinworm, whipworm, roundworm, and hookworm in patients two years and older. Mebendazole's poor absorption into the bloodstream means it primarily acts within the gastrointestinal tract, minimizing systemic side effects, which are generally mild and may include abdominal pain and diarrhea, especially with heavy infections.

Effective Alternatives to Mebendazole

Given the cost and availability issues with mebendazole in the U.S., healthcare providers and patients often turn to effective and more affordable alternatives. The primary options are albendazole and pyrantel pamoate.

Comparison of Anthelmintic Treatments


Feature	Mebendazole (Emverm)	Albendazole (Albenza)	Pyrantel Pamoate (Reese's)
Availability	Prescription only	Prescription only	Over-the-counter (OTC)
Cost	Very high (brand only)	Lower (generic available)	Low
Mechanism	Inhibits glucose absorption	Inhibits glucose absorption	Causes spastic paralysis of the worm
Kills Eggs? (Ovicidal)	Yes	Yes	No
Common Uses	Pinworm, whipworm, roundworm, hookworm	Pinworm, hookworm, tapeworms, roundworm	Primarily pinworm
Typical Dosing	Single dose or 3-day course	Single dose or multi-week courses	Single dose, repeated in 2 weeks

Albendazole: A benzimidazole similar to mebendazole, albendazole also inhibits glucose absorption in worms. It is better absorbed and treats both intestinal and systemic infections like neurocysticercosis. Studies indicate it's more effective than mebendazole against hookworm and equally effective for roundworm. It's available as a more affordable generic prescription.
Pyrantel Pamoate: Available over-the-counter as Reese's Pinworm Medicine, this is an accessible and low-cost option mainly for pinworms. It paralyzes worms via neuromuscular blockade. Unlike mebendazole and albendazole, it's not ovicidal, so a repeat dose after two weeks is recommended to target newly hatched worms.

Personal Hygiene and Prevention

Preventing reinfection is crucial alongside medication. Parasitic worm eggs can spread easily. Key preventive measures include:

Thorough handwashing with soap, especially after using the toilet and before eating.
Daily washing of the perianal region.
Frequent laundering of bed linens and underwear in hot water.
Discouraging nail-biting and scratching the anal area.
Cleaning toilet seats and household surfaces regularly.

Authoritative Link on Pinworm Prevention

Conclusion

The question 'Why is mebendazole no longer available?' is complex. In the U.S., its reduced availability is due to market forces – the discontinuation of the affordable brand Vermox and the high price of Emverm – not safety concerns. Mebendazole remains vital globally, but in the U.S., effective and more accessible alternatives exist. Prescription albendazole offers broader coverage and generic affordability. Over-the-counter pyrantel pamoate is a convenient, low-cost choice for pinworms. Consulting a healthcare provider is key for diagnosis and choosing the best treatment.

Frequently Asked Questions

No, mebendazole was not banned or removed from the market for safety or effectiveness reasons. The popular brand Vermox was discontinued by its manufacturer for business reasons.

Both Vermox and Emverm contain the same active ingredient, mebendazole. Vermox was a brand that has been discontinued in the U.S. Emverm is the current brand-name version available by prescription.

Emverm is expensive because it is a brand-name drug with no generic version currently on the U.S. market. This lack of competition allows the manufacturer to set a high price.

The most common and effective over-the-counter alternative for pinworms is pyrantel pamoate, sold under brand names like Reese's Pinworm Medicine. It is crucial to repeat the dose in two weeks as it does not kill worm eggs.

The effectiveness depends on the specific type of worm infection. For example, studies show albendazole is generally more effective against hookworm infections, while both are highly effective for roundworms (Ascaris). A doctor can determine the best choice.

While it may be tempting, purchasing medications from unverified online pharmacies is risky. These drugs may be counterfeit, contaminated, or unsafe. The FDA warns against this practice.

Pinworms are highly contagious, and asymptomatic infection among household members is common. Therefore, healthcare providers often recommend treating all members of the household simultaneously to prevent reinfection cycles.