Mebendazole

Sounds like 'meh-BEN-duh-zole'

Mebendazole is used to treat worm infections such as threadworms (also called pinworms), roundworms and hookworms. Find out how to take it safely and possible side effects.

Type of medicine Also called
  • Medication for treating worms (also called anthelmintics)
  • Vermox®
  • De-Worm®
  • Combantrin-1 with Mebendazole®

What is mebendazole?

Mebendazole is used to treat worms that live in the human bowel such as threadworms (also called pinworms), roundworms and hookworms. Read more about threadworm.

Mebendazole stops the worms from absorbing the sugars they need to survive. This kills the worms within a few days. Although mebendazole kills adult worms, it does not kill the eggs. Eggs can survive for up to 2 weeks outside your body on underwear or bedding, and in dust. So treating the infection also means you need to have good hygiene measures. See hygiene measures below.

How is mebendazole available in New Zealand?

In Aotearoa New Zealand, mebendazole is available as orange flavoured or chocolate flavoured tablets, chocolate squares or banana flavoured liquid.

Mebendazole can be bought over the counter from your local pharmacy or prescribed by your healthcare provider (doctor/GP or nurse).

Dose

  • The dose of mebendazole depends on the type of worms being treated.
    • Threadworms: 100 mg as a single dose. Reinfection is very common so a second dose may be needed after 2 weeks.
    • Whipworms, roundworms, hookworms: 100 mg 2 times a day for 3 days.
  • All household members, including adults and those without symptoms, should be treated with worm medicine at the same time.
  • Always take mebendazole exactly as your doctor or pharmacist has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

How to take mebendazole

  • You can take mebendazole with or without food.
  • It may be chewed, swallowed whole, or crushed and mixed with food.
  • Measure the liquid carefully with an oral syringe or measuring spoon. Shake the bottle well before measuring each dose.
  • After you take each dose, wash your underwear and bed linen, and vacuum your carpets.
  • You don't need to take worm medicine to prevent worms, it should only be used if someone in your home has them.

Precautions before taking mebendazole

  • Are you pregnant or breast-feeding?
  • Do you have a child under 2 years old in the family? 
  • Are you taking helminthic therapy?

If you answered yes to any of these questions, it’s important that you tell your doctor before you start taking mebendazole. Sometimes a medicine isn’t suitable or it can only be used with extra care. For example, you cannot buy mebendazole for children under 2 years old. 

Hygiene measures while taking mebendazole

Treating the infection also means you need to have good hygiene (clean habits). Follow these good hygiene practices to prevent threadworms or to stop spreading them to others:

  • Wash your hands carefully and often.
  • Avoid scratching around your bottom.
  • Keep your fingernails short.
  • Wash your clothes and bedding regularly.
  • Bathe and change your underwear every day.
  • Avoid sharing a bathtub or face cloths.
  • Vacuum your carpets often.

Possible side effects

Like all medicines, mebendazole can cause side effects, although not everyone gets them. Often side effects improve as your body adjusts to the new medicine.

Side effects What should I do?
  • Stomach discomfort
  • Tummy ache
  • Bloating (wind or gas)
  • Diarrhoea (runny poos)
  • Tell your doctor if these bother you. 
For more information on side effects, see the learn more section below or the consumer leaflet with the product.

Did you know that you can report a medicine side effect to the Centre for Adverse Reactions Monitoring (CARM)? Report a side effect to a product.

Learn more

The following links provide further information about mebendazole. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Mebendazole NZ Formulary, NZ
Mebendazole Patient Info, UK, 2017

References

  1. Mebendazole NZ Formulary, NZ
  2. Mebendazole NZ Formulary for Children, NZ
  3. Vermox Medsafe, NZ
Credits: Sandra Ponen, Pharmacist. Reviewed By: Maya Patel, Pharmacist Last reviewed: 07 Feb 2022