Worms in Humans: What to Know About Mebendazole, Ivermectin, and 5 Other Anthelmintics

When people think of an infection, they frequently think of bacterial, viral, or fungal ones. But parasitic infections can also happen.

Parasitic worms — or helminths — are one type of parasite. They’re most often found in developing parts of the globe, but they can affect people worldwide. Parasitic worms tend to spread through contaminated foods, contaminated drinks, or direct skin contact.

These infections can seem intimidating. But many effective treatments are available, including anthelmintic medications, which treat worm infections.

Types of anthelmintics

Some people group anthelmintics by their drug class. This can be confusing, though. Many find it easier to think of anthelmintics based on the type of worm they’re used to treat.

There are three main types of helminths, or parasitic worms. Some anthelmintics work broadly against multiple helminths and the infections they cause, while others treat very specific ones.

1. Nematodes (roundworms): This is one of the more diverse groups of worms. It includes whipworms, pinworms, hookworms, and more.

2. Cestodes (flatworms): This generally includes different types of tapeworms, such as pork tapeworm, beef tapeworm, and Asian tapeworm.

3. Trematodes (flukes): Some flukes are called blood flukes, while others are called tissue (lung, liver, intestine) flukes.

EXPERT PICKS: WHAT TO READ NEXT

• Pinworm infections: Pinworms may seem unsettling, but they’re not usually dangerous. Physicians break down what you need to know about identifying, treating, and preventing these infections.

• Emverm side effects: One antiparasitic medication you may receive is mebendazole (Emverm). It can cause side effects, but they’re often short-lived.

• Caring for your furry friend: Tapeworm infections don’t just affect humans — they can happen in dogs too. Here’s how to spot the symptoms and treat them.

To help narrow down what worm is in your system, you may be asked for a stool sample, blood draw, or even a CT scan or MRI. A physical exam may also be necessary. Once your healthcare professional identifies the worm, they’ll choose what treatment would likely work best.

Here, we’ll highlight what to know about seven notable anthelmintic medications. We won’t discuss older anthelmintics that have been discontinued in the U.S.

1. Mebendazole

Mebendazole (Emverm) is a prescription medication that comes as a chewable tablet for adults and kids age 2 years and older. It’s FDA approved to treat the following intestinal infections:

• Ascariasis, caused by a roundworm called Ascaris lumbricoides — the most common worm found in humans

• Trichuriasis, caused by a whipworm called Trichuris trichiura

• Enterobiasis, caused by a pinworm called Enterobius vermicularis

• Hookworm infections, caused by Ancylostoma duodenale or Necator americanus

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Mebendazole also has a few off-label uses. Your prescriber may recommend it for roundworm infections such as capillariasis, toxocariasis, or trichinellosis.

Mebendazole can fight most of these infections with just a few doses. Most people take a 100 mg tablet twice daily for 3 days. If you have a pinworm infection specifically, you'll take a single, 100 mg dose. However, if it doesn’t work with these short courses of the medication, you may be asked to take it for a few weeks. You may also be asked to repeat your dose after a couple weeks. Your prescriber will determine the best course and length of treatment for your type of infection.

Most of mebendazole’s side effects are gut-related. They should go away after you stop the medication, though. Mebendazole is also only available as a brand-name product. If affordability is an issue, ask your prescriber about the Emverm savings program. Eligible people may be able to pay as little as $5 for the medication.

2. Ivermectin

Ivermectin (Stromectol) is another prescription-only anthelmintic. It comes as a 3 mg tablet in both brand and generic formulations. It’s approved to treat two types of roundworm infections in adults and kids weighing at least 33 lbs (15 kg):

• Strongyloidiasis, caused by Strongyloides stercoralis

• Onchocerciasis (river blindness), caused by Onchocerca volvulus

Ivermectin is a go-to medication for both these conditions. You’ll likely just need to take one dose of the medication. But you may need to take several tablets at once, depending on your body weight. Ivermectin also has several possible off-label uses — such as ascariasis and trichuriasis — but it’s less preferred for these infections.

Dizziness, itchy skin, and nausea are all possible ivermectin side effects. Other side effects are possible too, but they should go away once your treatment is complete.

There are also ways to save on ivermectin. If your insurance doesn’t cover ivermectin, you can access the generic version for as little as $18.39 with a free GoodRx coupon. The brand-name version, Stromectol, may cost as little as $52.34.

Good to know: Topical forms of ivermectin (Sklice, Soolantra) are also available. They treat head lice and rosacea (skin reddening).

3. Moxidectin

Moxidectin is a prescription medication that’s relatively similar to ivermectin. It’s approved to treat onchocerciasis in people age 12 years and older. It’s a generic, 2 mg tablet that’s taken as a single dose (typically four 8 mg tablets at once).

Ivermectin is often preferred over moxidectin. However, some data shows that moxidectin works better to slow down how fast the condition spreads. It also lasts longer in your body, which may be beneficial for some infections. Your prescriber will decide if ivermectin or moxidectin would be better for you.

4. Pyrantel pamoate

Pyrantel pamoate (Reese's Pinworm Medicine, others) is an over-the-counter (OTC) anthelmintic. It comes as a 144 mg/1 mL (the equivalent of 50 mg pyrantel base) oral suspension. Adults and kids age 2 years and old can take it for enterobiasis, or pinworm infections. It’s also sometimes prescribed off-label for similar infections, such as ascariasis or trichostrongyliasis.

Pyrantel pamoate is a preferred medication for enterobiasis. Its convenience is also a plus. It’s widely available at pharmacies in the U.S., and it’s typically taken as a single, weight-based dose. Some people may be instructed to take a second dose 2 weeks later. But don’t repeat your dose unless told to by your prescriber.

Pyrantel pamoate is generally well tolerated. It occasionally causes stomach pain, nausea, and other temporary gut-related side effects.

Tip: If someone in your family catches pinworm, it’s a good idea for everyone that lives in the household to get treated for it. This helps stop the spread of infection.

5. Albendazole

Albendazole is a prescription-only 200 mg tablet. It’s approved to treat tapeworm infections in adults and kids, and has many off-label uses, too. Approved uses include:

• Cystic echinococcosis (hydatid disease), caused by Echinococcus granulosus. This is a tapeworm infection that causes cysts throughout the body.

• Neurocysticercosis, caused by Taenia solium. This is a tapeworm infection that involves the brain.

Compared to the medications above, albendazole treatment lasts for a longer period of time. If you have cystic echinococcosis, you’ll likely take albendazole twice daily for 28 days. This is followed by a 14-day break. You’ll repeat this process two more times for a total of three cycles. If you have neurocysticercosis, you’ll likely take it twice daily for 1 to 4 weeks without additional cycles. Albendazole is a first-choice treatment for these infections.

Common side effects of albendazole include nausea, stomach pain, and headache. These usually resolve after finishing the treatment. For longer treatments, your prescriber may monitor your liver function and blood counts as a precaution.

If cost is an issue and/or your insurance won’t cover the medication, you may be able to get a month’s supply of albendazole for as little as $115.94 with a GoodRx coupon.

6. Praziquantel

Praziquantel is a prescription-only 600 mg tablet. It’s approved for adults and kids age 1 year and older, but more safety research has been done involving children age 4 and older. It’s a go-to medication for fluke infections, especially:

• Schistosomiasis, caused by blood flukes

• Clonorchiasis, caused by the liver fluke Clonorchis sinensis

• Opisthorchiasis, caused by the liver fluke Opisthorchis viverrini

Praziquantel is also an effective, off-label treatment for paragonimiasis (lung flukes), fasciolopsis (intestinal flukes), and certain tapeworm infections.

Praziquantel is a short-term treatment. Treatment usually lasts just 1 day. Your specific dosage will depend on your body weight, but you’ll likely take a dose 3 times throughout the day. You may or may not be asked to split the tablets into smaller portions so you can take a precise dose that’s appropriate for your body weight.

Again, praziquantel’s side effects tend to be temporary. But make sure to tell a healthcare professional if you experience any problematic episodes of fatigue, upset stomach, or fever.

If your insurance doesn’t cover praziquantel, a typical 1-day supply may cost as low as $132.74.

7. Triclabendazole

Triclabendazole (Egaten) is a prescription medication that comes as a brand-name 250 mg tablet. It’s approved for adults and children age 6 years and older.

Triclabendazole is approved to treat fascioliasis, an infection caused by liver flukes. It’s a first-choice medication for fascioliasis, and it’s relatively affordable. A course of the medication costs as low as $2.50.

This medication is another short-term treatment. Most people take just 2 doses, spaced apart by about 12 hours.

Triclabendazole may cause side effects such as stomach pain, increased sweating, and appetite changes. It may also contribute to QT prolongation (an abnormal heartbeat), but this isn’t common. These side effects shouldn’t last long, but make sure to reach out to a healthcare professional if anything feels worrisome or severe.

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Written by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Reviewed by:

Bailey E. Eason, PharmD, MS, BCPS

Bailey Eason has been licensed for 6 years and has held licenses in three states (North Carolina, Virginia, and Illinois). She has held positions as a health-system pharmacy administration resident, operating room pharmacy manager, pharmacy manager of clinical operations: surgery, neurology and controlled substances, and most recently as program director  of drug diversion for a large academic health system.

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