Mebendazole (Oral)

Prescribed to patients with parasitic worm infestations, Mebendazole can be used to treat giardia, pinworm disease, com/health/ascariasis/">ascariasis, hookworm infections and hydatid disease.


Also known as helminths, parasitic worms live and feed in the human body. Often, parasitic worms gain nourishment from the patient's dietary intake and this is how they continue to survive. However, patients may suffer from weakness, malnutrition, disease and/or nutritional deficiencies as a result of the parasites taking nourishment from their host.

While many parasitic worms reside in the intestinal tract, some may be present in other areas of the body. Without effective treatment, parasitic infestations can go on for years and may worsen over time. Infestations can cause various symptoms but are commonly associated with abdominal pain, nausea, diarrhea, passing gas, bloating, vomiting, feelings of fullness, tiredness and/or stomach tenderness and pain.

As an anthelmintic, Mebendazole is predominantly used to treat nematode infestations, which may include hookworm, roundworm, whipworm, pinworm, threadworm and trichinosis within the digestive tract.

Mebendazole prevents the synthesis of microtubules within parasitic worms and destroys extant cytoplasmic microtubules within the intestinal cells of the parasite. This prevents the parasites from absorbing key nutrients and leads to their immobilization and death.

Although Mebendazole is effective in treating mild-to-moderate parasitic infestations, additional treatment may be required for severe infestations. As Mebendazole kills parasites fairly slowly, if it is used in isolation to treat heavy infestations, some parasites could migrate into other areas of the body and cause further complications. By combining Mebendazole with Piperazine, however, the parasites are paralyzed prior to death and are unable to affect any other areas of the body.

Taken orally, treatment with Mebendazole may last from one to three days, depending on the severity of the patient's condition. In most cases, Mebendazole is effective in treating the infestation and patients may not require any further treatment once Mebendazole has taken effect.

Conditions Treated

  • Parasitic worm infestations

Type Of Medicine

  • Anthelmintic

Side Effects

When patients use any type of medication, it could cause them to suffer adverse effects. Often, side-effects are more pronounced when patients first start using Mebendazole but they should decrease over time. For example, patients may exhibit the following side-effects when they begin taking Mebendazole:

  • Bloated
  • Stomach or abdominal upset or pain
  • Full feeling
  • Passing gas
  • Excess gas or air in the intestines or stomach
  • Thinning of the hair or hair loss
  • Loss of appetite
  • Weight loss

If the above side-effects are not severe, patients may not require additional medical treatment for them. However, if patients are concerned about the presence of side-effects or if the side-effects do not diminish over time, patients should access medical advice.

In addition to this, patients should notify a healthcare practitioner immediately if they experience the following side-effects whilst taking Mebendazole:

  • Tarry, black stools
  • Redness of the skin
  • Chills
  • Fever, may be with or without chills
  • Difficult or painful urination
  • Convulsions
  • Hoarseness or cough
  • General feeling of weakness or tiredness
  • Unusual weakness or tiredness
  • Dark urine
  • Welts, hives or itching
  • Large, hive-like swelling on the eyelids, face, lips, throat, tongue, feet, legs, hands or sex organs
  • Rash on the skin
  • Pain in the stomach or upper right abdomen
  • Unusual bruising or bleeding
  • Light-colored stools
  • Pain in the side or lower back
  • Nausea and vomiting
  • Sore throat
  • Pale skin
  • White spots, ulcers or sores in the mouth or on the lips
  • Loosening, peeling or blistering of the skin
  • Yellowing of the skin or eyes
  • Diarrhea
  • Tightness in the chest
  • Difficulty with swallowing
  • Irritated, red eyes
  • Dizziness
  • Red skin lesions, sometimes with a purple center
  • Fast heartbeat
  • Muscle or joint pain

Patients should also access medical assistance if they experience any side-effects which are not listed above, whilst they're using Mebendazole tablets.


When patients are prescribed Mebendazole, their dose will depend on the type of medication they're given and the nature of their infestation, as well as their age, weight and medical history.

If patients are prescribed Mebendazole as a chewable tablet for the treatment of pinworms, for example, they are usually advised to take 100mg once per day for just one day. However, this treatment may need to be repeated after three weeks if the infestation is still present. Whilst pediatric patients may be prescribed this form of Mebendazole, a smaller dose of medication may be given to younger children or infants.

Alternatively, if patients are given Mebendazole as a chewable tablet for the treatment of common hookworms, roundworms and/or whipworms, they may be instructed to take 100mg, twice per day, for a period of three days. Usually, patients should take one chewable tablet in the morning and one in the evening. If prescribed to pediatric patients, a smaller dose may be given to patients who are under the age of two years or an alternative medicine may be prescribed.

In some cases, a different brand of chewable Mebendazole tablet can be given to treat whipworm and/or roundworms. If so, the patient may be instructed to take 500mg once per day, for just one day. If used to treat pediatric patients, this form of Mebendazole should not be given to patients under the age of one year and smaller doses may be given to children over this age.

Generally, patients can take Mebendazole chewable tablets with or without food. However, patients who are taking relatively high doses of Mebendazole for heavy infestations may be advised to take Mebendazole with food. If so, the medication may work best if taken with high-fat foods, such as ice cream or whole milk. However, patients should confirm this with their physician and should not consume these foods if they are on a low-fat or restricted diet.

Whilst some chewable tablets can be swallowed whole if the patient prefers, this is not true of all brands. Patients should, therefore, read the medication guide and manufacturer's instructions before using this medicine. In addition to this, patients should ensure that they have been given the correct brand of medication when it is prescribed to them. The instructions for one brand may not apply to another brand of Mebendazole chewable tablets.

Some tablets, for example, can be added to two or three milliliters of water and administered via a dosing syringe, whilst other brands can be mixed with food. If patients find it difficult to chew Mebendazole tablets, they should ask their pharmacist or physician how else they can take the medication.

Patients should take Mebendazole in accordance with their doctor's instructions. It is important that patients finish the course of medication, even if their symptoms subside. If patients stop taking Mebendazole too early, the infestation may still be present and may worsen.

If patients forget to take a dose of Mebendazole, they should take it as soon as they remember to do so. However, if their next dose of Mebendazole is due soon, patients will need to skip the missed dose and continue with their normal treatment schedule. Patients should not attempt to take a double or extra dose of Mebendazole, even if a previous dose has been missed.

If patients are unsure how or when to take Mebendazole, they should contact their physician or pharmacist for advice.

Potential Drug Interactions

As some medicines can interact with each other, it may not be appropriate to take Mebendazole with certain other medications. Before using Mebendazole, patients should tell their doctor if they are using any other prescription medicines, over-the-counter medications, supplements and/or vitamins.

For example, taking Mebendazole alongside the following medicine is not usually advisable:

  • Metronidazole

However, if patients are prescribed Mebendazole in conjunction with the above medicine, their dose may be altered or they may be advised to take their medications at specific times in order to try and prevent an interaction occurring.

Once patients have started to use Mebendazole, they should obtain medical advice before using any new medicines, vitamins and/or supplements.


If patients have any other existing health problems, they should tell their doctor before they begin taking Mebendazole. Similarly, if they have any historical health problems, they should disclose them to their physician before Mebendazole is prescribed to them. There are some conditions which can affect the use of Mebendazole and these may include:

Mebendazole can be used to treat pediatric patients with parasitic worm infestations. However, some brands are only suitable for patients over the age of two years, whereas others can be prescribed to patients over the age of one year. The patient's physician will determine which form of treatment is most appropriate for them.

Unless advised otherwise, patients do not need to adhere to a special diet, fast, or use laxative or enemas before taking Mebendazole.

Generally, patients will notice an improvement in their symptoms whilst they are taking Mebendazole. However, if symptoms worsen or if they continue after the course of treatment has been completed, patients should consult their physician for further advice.

When taking Mebendazole, the patient's white blood cell count may be temporarily lowered. Due to this, patients may be more susceptible to infections and illnesses. If patients exhibit symptoms of an infection or feel unwell, they should seek medical help straight away. The following symptoms may indicate that a patient has developed an infection:

  • Fever
  • Chills
  • Hoarseness
  • Pain in the lower back or side
  • Difficult or painful urination
  • Cough

If patients are being treated for pinworms, other members of their household may also require treatment. Pinworms can easily be transferred from one person to another so it's important that members of the household are treated at the same time as this can prevent further infestations from occurring.

If patients are prescribed Mebendazole for the treatment of whipworms or hookworms, they may also be prescribed iron supplements. As these conditions can cause anemia, patients may be required to take iron supplements whilst they are taking Mebendazole and for approximately six months after they have completed the treatment.

If Mebendazole is taken in conjunction with Metronidazole, patients could experience skin reactions and should seek medical help if they develop the following symptoms:

  • Loosening, peeling or blistering of the skin
  • Severe skin rash or acne
  • Ulcers or sores on the skin
  • Skin lesions, which may be red in color
  • Fever or chills

After taking Mebendazole, it is possible that an infestation could recur. In order to prevent this, patients should take the following precautions:

  • Washing fingernails and hands regularly, particularly after using the toilet and before eating
  • Keeping all surfaces clean, particularly in the bathroom
  • Washing vegetables and fruits thoroughly and ensure they are cooked fully
  • Cleaning rooms with a damp mop or vacuum at least once per day during and following treatment
  • Avoiding dry sweeping or dusting
  • Washing all pajamas, night clothes and bedding
  • Wearing tight underwear during both the day and night, and changing them at least once per day
  • Wearing shoes

As Mebendazole could cause harm to an unborn fetus, patients must tell their physician if they are pregnant before they use this medication.

It is not known if Mebendazole can be excreted in breast milk or what level of harm it could cause if it was transferred to an infant in this way. Due to this, patients are generally advised not to breastfeed whilst taking Mebendazole. As the medication may remain in the patient's system, they should obtain medical advice before breastfeeding, even if they have finished the course of treatment.

Before taking Mebendazole, patients should tell their doctor if they have any known allergies. This includes allergies to medicines, animals, preservatives, dyes, foods and other substances. In rare cases, patients may develop an allergic reaction when using Mebendazole. If so, they will need urgent medical treatment. If an allergic reaction occurs, patients may experience the following symptoms:

  • Hives
  • Wheezing
  • Itching
  • Shortness of breath
  • Hoarseness
  • Difficulty swallowing
  • Trouble breathing
  • Swelling, which could affect either the face, mouth, lips, tongue, throat or hands


When keeping medicines, such as Mebendazole, at home, patients must ensure that they are kept in a safe location and that children and/or pets cannot gain access to them. If any member of the household takes Mebendazole which has not been prescribed to them or takes an excessive amount of Mebendazole, emergency help must be sought.

Keeping Mebendazole in a locked medicine cabinet or lockable medicine box may help to prevent accidental ingestion of this medicine.

In order to store Mebendazole properly, patients should follow the manufacturer's instructions. In most cases, Mebendazole can be stored at room temperature but should not be exposed to light, moisture or heat.

If patients are advised to stop taking Mebendazole or if the medication reaches its expiry date, it will need to be disposed of. Some brands of Mebendazole must be thrown out if they have been open for longer than one month so patients should keep a record of when they first used the medication.

However, Mebendazole should not be thrown out with normal household waste as it may pose a risk to other people. Instead, patients should contact their physician's office or pharmacist and make use of a specialist medicine disposal service.


When patients are suffering from a parasitic worm infestation, they can experience a number of distressing symptoms. Abdominal pain, nausea, bloating, vomiting, tiredness and/or a skin rash can all be signs of an infestation and the patient's symptoms may worsen over time.

However, parasitic worm infestations can usually be treated successfully. It may be easier to treat an infestation which is in its infancy so patients shouldn't hesitate to obtain medical help if they are exhibiting symptoms associated with a worm infestation.

Although Mebendazole is effective in targeting parasitic worms, it is not thought to be particularly harmful to patients. Due to this, Mebendazole can be used to kill the worms which are present in the patient's body, without causing damage to the surrounding tissues or the intestinal walls.

In some cases, however, a parasitic worm infestation can require more than one treatment. If symptoms persist after initial treatment with Mebendazole, patients may be advised to use the medication again at a later date.

Whilst worm infestations can be upsetting for the patient, they are not an uncommon problem and can usually be resolved with non-invasive treatment. When Mebendazole is used to treat infestations, parasitic worms can usually be killed and destroyed with just one or two courses of treatment.