About mebendazole

Threadworms are relatively common and can be easily passed from one person to another, but they are not usually serious. They are small parasites which live inside the bowel for a short time. The female lays her eggs at night around the back passage which causes an 'itchy bottom'. The itching causes scratching, which allows the tiny eggs to get under the fingernails. If the fingers are then put in the mouth, for example during sleep, the eggs may be swallowed. The worms then develop in the bowel and produce more eggs. Eggs can easily get onto bedding, carpets, towels and into the house dust. They can also get onto food and be swallowed.

Mebendazole works by preventing the worms from absorbing the essential sugars which they need for survival. This leads to the death of the worm within a few days. Mebendazole kills the worms, but not the eggs. Because of this, it is important in the six weeks after taking mebendazole that you and your family follow the advice below to stop re-infection.

Roundworms, hookworms and whipworms are all parasites which may be caught by travellers to tropical countries who eat contaminated food.

Before taking mebendazole

Before taking mebendazole make sure your doctor or pharmacist knows:

• If you are pregnant or breast-feeding.
• If you are taking other medicines, including those available to buy without a prescription, herbal or complementary medicines.
• If you have ever had an allergic reaction to this or to any other medicine.

How to take mebendazole

• Before beginning treatment, read the manufacturer's printed information leaflet.
• Take mebendazole exactly as you have been told by your doctor or pharmacist. If you have been given tablets, these may be chewed or swallowed whole.
• If you have been given mebendazole for threadworm it is usually taken as a single dose. A second dose may be necessary after 2 weeks if re-infection occurs.
• Make sure all members of your family are treated for threadworms on the same day.
• If you have been prescribed mebendazole for other types of worm infection, follow the instructions you have been given carefully, and remember to take the full course of treatment.

Getting the most from your treatment

• To prevent further threadworm infection, everyone in the family (whether or not they have any symptoms) should be treated, and they should all follow the measures to stop threadworm re-infection as stated below for at least 6 weeks.
• Mebendazole is not recommended for children under 2 years of age. If your family is being treated and you have a child under 2 years old, ask your doctor or pharmacist for advice.

How to prevent threadworm re-infection:

• Wash your hands and scrub your nails before preparing or eating a meal, and after each visit to the toilet.
• Wear underwear or pyjamas in bed.
• Take a bath or a shower immediately after getting up in the morning.
• Disinfect the toilet seat, toilet handle and door handle of the bathroom regularly.
• Keep your fingernails short and clean, and avoid biting your nails or sucking your fingers.
• Make sure each member of your family uses a separate towel.
• Change and wash your clothing and bedding frequently.
• Vacuum clean the bedroom carpets regularly.
• Disinfect the kitchen work surfaces regularly.

Can mebendazole cause problems?

Along with their useful effects, all medicines can cause unwanted side-effects, although side-effects after taking mebendazole are rare.

Important: If you develop either of the following, contact a doctor straight away:

• A skin reaction such as a severe rash, itching or blistering.
• Convulsions.

If you experience any other worrying symptoms which you think may be due to this medicine, discuss them with your doctor or pharmacist.

How to store mebendazole

• Keep all medicines out of the reach and sight of children
• Store in a cool, dry place, away from direct heat and light

Important information about all medicines