Mebendazole

What is mebendazole?

Mebendazole is an anti-parasitic medicine used to treat worm infections that you can get on prescription or buy in a pharmacy. It works by stopping worms from absorbing glucose, which they need to survive. Without glucose, the worms lose energy, die, and are passed out of the body in the stool[1].

What is mebendazole used for?

Mebendazole is commonly used to treat infections caused by parasitic worms, including[1]: 

• Threadworms (pinworms) – the most common type in the UK 

• Roundworms 

• Whipworms 

• Hookworms 

How does mebendazole work?

Mebendazole prevents worms from absorbing glucose, disrupting their ability to generate energy. This leads to the death of the worms, which are then eliminated from the body[1]. 

Who can take mebendazole?

This medicine is generally suitable for adults and children over 2 years old. It is not usually recommended for children under 2 years old unless prescribed, pregnant women, especially during the first trimester, and if you are breastfeeding or trying to get pregannt[1]. 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2]. 

What is the typical dosage of mebendazole?

For threadworms, a single 100mg dose is usually effective. If reinfection is suspected, a second dose may be taken after two weeks. For other types of worms: treatment may involve 100mg twice daily for three days, but your doctor will decide based upon your individual situation[1]. 

How do you take mebendazole?

Mebendazole comes as a banana flavour liquid and orange flavour tablets. It can be taken with or without food. Tablets can be chewed or crushed if needed. Practicing good hygiene, such as keeping nails short, handwashing, showering or bathing in the morning, and regular cleaning of clothes and bedding, is important to prevent reinfection[1]. 

Can you stop taking mebendazole?

For threadworms, a single dose is often enough. If you’re treating another type of infection, it’s important to complete the full course, even if symptoms improve sooner[1]. 

What do you do if you take too much mebendazole?

Taking too much is unlikely to be dangerous, but it may cause stomach pain, diarrhoea or vomiting. Contact your GP or NHS 111 if you’ve taken more than recommended[1]. 

What do you do if you forget to take mebendazole?

If you forget a dose, take it when you remember. If it’s nearly time for your next dose, skip the missed one. Do not take two doses at once[1]. 

What medicines can’t you take with mebendazole?

Some medicines may interact with mebendazole, such as[1]: 

• Metronidazole – may cause rare but serious skin reactions 

• Cimetidine – can increase mebendazole levels in the body 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of mebendazole?

Most people tolerate mebendazole well. Possible side effects include[1]: 

• Mild stomach pain 

• Diarrhoea 

• Bloating and wind 

Stop taking mebendazole immediately and call a doctor or 111 if the whites of your eyes or your skin turn yellow. This can be a sign of liver problems[1]. 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about mebendazole

How quickly does mebendazole work? 
It starts working within a few hours, and most worms are eliminated within a few days[1]. 

Do I need a second dose of mebendazole? 
A second dose may be recommended two weeks after the first for threadworm infections to prevent reinfection[1]. 

Can children take mebendazole? 
Yes, children over 2 years old can usually take it safely[1]. 

Should the whole household be treated? 
Yes, for threadworms, it’s advised that everyone in the household is treated, even if they have no symptoms and all practice good hygeine[1].  

For the official NHS guide to mebendazole, visit their website.