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Other drug names: A-Am An-Az B C-Ch Ci-Cz D-Dh Di-Dz E F G H I-J K-L M-Mh Mi-Mz N-Nh Ni-Nz O P-Pl Pm-Pz Q-R S-Sn So-Sz T-To Tp-Tz U-V W-Z 0-9   

Praziquantel (Systemic)

Brand Names

In the U.S.-

  • Biltricide


  • Anthelmintic, systemic


Praziquantel (pray-zi-KWON-tel) belongs to the family of medicines called anthelmintics ( ant-hel-MIN-tiks ) . Anthelmintics are used in the treatment of worm infections.

Praziquantel is used to treat blood fluke infections. These are also known as snail fever, schistosomiasis ( shis-toe-soe-MYE-a-siss) , or bilharziasis (bil-har-ZYE-a-siss) . Praziquantel may also be used for other worm infections as determined by your doctor. However, it will not work for pinworms or other roundworms.

Praziquantel works by causing severe spasms and paralysis of the worms' muscles. Some kinds of worms are then passed in the stool. However, you may not notice them since they are sometimes completely destroyed in the intestine.

Praziquantel is available only with your doctor's prescription, in the following dosage form:

  • Tablets (U.S.)

Before Using This Medicine

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 praziquantel, the following should be considered:

Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to praziquantel. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy- Studies have not been done in humans. Studies in rats and rabbits given up to 40 times the usual human dose have not shown that praziquantel causes birth defects. However, praziquantel has been shown to cause a greater chance of miscarriage in rats given 3 times the human dose.

Breast-feeding- Praziquantel passes into the breast milk. You should stop breast-feeding on the day you begin taking praziquantel. Do not restart breast-feeding until 72 hours after treatment is completed. During this time the breast milk should be squeezed out or sucked out with a breast pump and thrown away.

Children- This medicine has been tested in a limited number of children 4 years of age or older and, in effective doses, has not been reported to cause different side effects or problems in children over 4 years of age than it does in adults.

Older adults- 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 praziquantel in the elderly with use in other age groups.

Other medicines- 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. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other medical problems- The presence of other medical problems may affect the use of praziquantel. Make sure you tell your doctor if you have any other medical problems, especially:
  • Liver disease-Patients with moderate to severe liver disease may have an increased chance of side effects
  • Worm cysts in the eye-The death of worm cysts in the eye caused by praziquantel may cause damage to the eyes

Proper Use of This Medicine

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

Praziquantel has a bitter taste that may cause gagging or vomiting. The bitter taste may be more noticeable if the tablets are held in the mouth or chewed. Therefore, do not chew praziquantel tablets . Swallow them whole with a small amount of liquid during meals.

To help clear up your infection completely, take this medicine exactly as directed by your doctor for the full time of treatment. Do not miss any doses .


The dose of praziquantel 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 praziquantel. If your dose is different, do not change it unless your doctor tells you to do so.

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 taking praziquantel .

  • For the treatment of clonorchiasis (Chinese or Oriental liver fluke) and opisthorchiasis (liver flukes):
    • Adults and children 4 years of age and older: Dose is based on body weight and will be determined by your doctor. This dose is taken three times a day for one day.
    • Children up to 4 years of age: Dose must be determined by the doctor.
  • For the treatment of schistosomiasis:
    • Adults and children 4 years of age and older: Dose is based on body weight and will be determined by your doctor. This dose is taken two or three times a day for one day.
    • Children up to 4 years of age: Dose must be determined by the doctor.

Missed dose-

If you do 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.


To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

It is important that your doctor check your progress after treatment. This is to make sure that the infection is cleared up completely.

If your symptoms do not improve after you have taken this medicine for the full time of treatment, or if they become worse, check with your doctor.

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. If any of these side effects occur, do not drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert while you are taking praziquantel and for 24 hours after you stop taking it.

Side Effects of This Medicine

Along with its needed effects, a medicine may cause some unwanted effects. The following side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

  • More common
    • Abdominal or stomach cramps or pain;  bloody diarrhea;  dizziness;  drowsiness;  fever;  headache ;  increased sweating;  loss of appetite;  general feeling of discomfort or illness ;  nausea or vomiting 

  • Less common
    • Skin rash, hives, or itching 

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

Additional Information

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, praziquantel is used in certain patients with the following medical conditions:

  • Some kinds of fluke infections
  • Some kinds of tapeworm infections

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT