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Thiabendazole

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  • Confusion
  • Diarrhea (severe)
  • Hallucinations (seeing, hearing, and feeling things that are not there)
  • Irritability
  • Loss of appetite
  • Nausea and vomiting (severe)
  • Numbness or tingling in the hands or feet

Less common

  • Skin rash or itching

Check with your doctor as soon as possible if any of the following side effects occur:

Rare

  • Aching of joints and muscles
  • Blurred or yellow vision
  • Chills
  • Convulsions (seizures)
  • Dark urine
  • Fever
  • Lower back pain
  • Pain or burning while urinating
  • Pale stools
  • Redness, blistering, peeling, or loosening of skin
  • Unusual feeling in the eyes
  • Unusual tiredness or weakness
  • Yellow eyes and skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Dizziness
  • Drowsiness
  • Dryness of eyes and mouth
  • Headache
  • Ringing or buzzing in the ears

This medicine may cause the urine to have an asparagus-like or other unusual odor while you are taking it and for about 24 hours after you stop taking it. This side effect does not need medical attention.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Precautions

It is important that your doctor check your progress at regular visits. This is to make sure that the infection is cleared up completely.

Thiabendazole may cause blurred vision or yellow vision. It may also cause some people to become dizzy, drowsy, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert or able to see well. If these reactions are especially bothersome, check with your doctor.

Good health habits are required to help prevent reinfection. These include the following:

  • For creeping eruption (cutaneous larva migrans) or visceral larva migrans (toxocariasis):
    • Keep dogs and cats off beaches and bathing areas.
    • Treat household pets for worms (deworm) regularly.
    • Cover children’s sandboxes when not being used.
    • These measures help to prevent contamination of the sand or soil by worm larvae from the animals’ wastes. This helps to keep children from picking up the larvae when they put their hands in their mouths after touching contaminated sand or soil.
  • For pork worms (trichinosis):
    • Cook all pork, pork-containing products, and game at not less than 140 °F (60 °C) until well done (not pink in the center) before eating. This will kill any trichinosis larvae that may be in the meat.

Proper Use

No special preparations (for example, special diets, fasting, other medicines, laxatives, or enemas) are necessary before, during, or immediately after treatment with thiabendazole.

Thiabendazole is best taken after meals (breakfast and evening meal). This helps to prevent some common side effects such as nausea, vomiting, dizziness, or loss of appetite.

Doctors may also prescribe a corticosteroid (a cortisone-like medicine) for certain patients with pork worms (trichinosis), especially for those with severe symptoms. This is to help reduce the inflammation caused by the pork worm larvae. If your doctor prescribes these 2 medicines together, it is important to take the corticosteroid along with thiabendazole. Take them exactly as directed by your doctor. Do not miss any doses.

For patients taking the oral liquid form of thiabendazole:

  • Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

For patients taking the chewable tablet form of thiabendazole:

  • Tablets should be chewed or crushed before they are swallowed.

To help clear up your infection completely, take this medicine exactly as directed by your doctor for the full time of treatment . In some patients a second course of this medicine may be required to clear up the infection completely. Do not miss any doses.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (oral suspension or tablets):
    • Adults and children over 13.6 kilograms (30 pounds) of body weight:
      • For cutaneous larva migrans and strongyloidiasis: Dose is based on body weight and will be determined by your doctor. The dose is taken two times a day for two days.
      • For trichinosis: Dose is based on body weight and will be determined by your doctor. The dose is taken two times a day for two to four days.
      • For visceral larva migrans: Dose is based on body weight and will be determined by your doctor. The dose is taken two times a day for seven days.
    • Children up to 13.6 kilograms (30 pounds) of body weight: Dose must be determined by the doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

This medicine has been tested in children over 13.6 kg of body weight (30 pounds). In effective doses, it has not been reported to cause different side effects or problems in children than it does in adults.

Geriatric

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of thiabendazole in the elderly with use in other age groups.

Pregnancy

Pregnancy Category Explanation
All Trimesters C Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Theophylline

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Kidney disease or
  • Liver disease—Patients with kidney and/or liver disease may have an increased chance of side effects

Description

Thiabendazole belongs to the family of medicines called anthelmintics. Anthelmintics are medicines used in the treatment of worm infections.

Thiabendazole is used to treat:

  • creeping eruption (cutaneous larva migrans);
  • pork worms (trichinosis);
  • threadworms (strongyloidiasis); and
  • visceral larva migrans (toxocariasis).

This medicine may also be used for other worm infections as determined by your doctor.

Thiabendazole is available only with your doctor’s prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, thiabendazole is used in certain patients with the following medical conditions:

  • Capillariasis
  • Dracunculiasis
  • Trichostrongyliasis