The side effects listed in the prescribing information for mebendazole are loss of appetite, belly pain, diarrhea, gas, nausea, vomiting and rash. Rarer but serious reports include drops in certain white blood cells, serious allergic reactions, severe skin reactions when it is taken with metronidazole, and convulsions in infants under 1 year old.

Mebendazole is a prescription antiparasitic used for certain intestinal worm infections. The 222 mg mebendazole capsule Get It Prescribed provides is a compounded preparation that is not FDA-approved and is not a generic of or substitute for the brand-name 100 mg mebendazole chewable tablet. As with any prescription medicine, the decision to prescribe it, and at what dose, rests with your licensed provider after reviewing your health history — the information below is educational and does not replace that individualized review.

How mebendazole works

Mebendazole interferes with the way susceptible parasites absorb and use glucose, which leads to loss of energy, immobilization, and death of the parasite. Because it is poorly absorbed from the gut, most of its activity stays localized in the intestine where these parasites live. Learn more on the mebendazole medication page and see the process end-to-end at how it works.

Common side effects of mebendazole

According to the prescribing information for the brand-name mebendazole chewable tablet, adverse reactions reported in clinical trials include:

• Loss of appetite (anorexia)
• Abdominal pain
• Diarrhea
• Flatulence
• Nausea and vomiting
• Rash

Tell your provider about any side effect that bothers you or does not go away.

Warnings from the label you should know

The prescribing information lists specific warnings:

• Convulsions: reported in infants under age 1 during post-marketing use.
• Hematologic effects: agranulocytosis and neutropenia (drops in certain white blood cells) have been reported with higher doses or prolonged use; blood counts may be monitored in those situations.
• Metronidazole interaction: concomitant use of mebendazole with metronidazole has been associated with serious skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis), so this combination should be avoided. See more in our overview of drug interactions.

Table: what the label reports

| Reaction type | Details | Source | |---|---|---| | Common | Abdominal pain, diarrhea, nausea, flatulence, rash | Mebendazole prescribing information, clinical trials | | Serious but rare | Neutropenia, agranulocytosis | Mebendazole prescribing information, warnings | | Drug interaction risk | Severe skin reactions with metronidazole | Mebendazole prescribing information, warnings | | Contraindication | Known hypersensitivity to mebendazole or excipients | Mebendazole prescribing information, contraindications |

Who should be cautious

The label contraindicates mebendazole only for people with known hypersensitivity to the drug or its ingredients. Your provider will also ask about pregnancy, liver conditions, and other medications, since these can affect whether mebendazole is appropriate — see who should not take these medications for more detail.

When to contact your provider

Any side effect that is severe or persistent warrants prompt contact with your provider. Signs of a serious allergic or skin reaction, such as swelling of the face, lips, tongue or throat, trouble breathing, hives, or blistering or peeling skin, need emergency care right away. Keep a simple symptom log noting when a side effect started and how long it lasted, since this detail helps your provider decide whether monitoring, dose adjustment, or a different approach makes sense. If you're comparing options, our ivermectin vs. mebendazole comparison explains how the two are used differently, and which parasites mebendazole's labeling covers covers which infections its labeling actually addresses.

Related questions

What are the most common side effects of mebendazole?

The prescribing information lists loss of appetite, stomach pain, diarrhea, gas, nausea, vomiting and rash as the side effects reported in clinical trials. Rare but serious reports include low white blood cell counts, serious allergic reactions, and severe skin reactions when mebendazole is taken with metronidazole. Tell your provider about any side effect that bothers you or does not go away.

Can I take mebendazole with food?

Yes. The prescribing information for the brand-name chewable tablet says it can be chewed, swallowed, or crushed and mixed with food, and no fasting or special preparation is required. Follow the specific instructions your prescribing provider gives you for your situation.

Is it safe to take mebendazole with metronidazole?

The prescribing information advises avoiding this combination because it has been associated with serious skin reactions. Always give your provider a full list of medications, including anything prescribed by another clinician, before starting mebendazole.

Why do I have stomach symptoms after taking mebendazole?

Abdominal pain, diarrhea, and gas are among the most commonly reported reactions in clinical trials. Mention persistent or severe symptoms to your provider.

Does mebendazole affect blood counts?

The label notes that neutropenia and agranulocytosis have been reported, generally with higher doses or longer courses than are typical for standard treatment. Your provider may recommend monitoring in specific circumstances.

When you are ready to start, you can get mebendazole prescribed online — an independent licensed provider reviews every request and prescribes only when it is clinically appropriate. Prescriptions are not guaranteed.

See mebendazole information for labeled interactions and adverse reactions.

Sources

• DailyMed: mebendazole chewable tablet prescribing information — full prescribing information.
• MedlinePlus — Mebendazole — patient-friendly summary of side effects and precautions.
• CDC — About Pinworm Infection — background on a labeled indication for mebendazole.