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Praziquantel is a tablet that is taken by mouth to treat infections caused by certain types of worms. The most common side effects are stomach discomfort, a general feeling of being unwell, headache, dizziness, fever, and itching. Before taking praziquantel, make sure to tell your healthcare provider about any health conditions or medicines you are taking.

Uses

What is praziquantel used for?

Praziquantel is commonly used to treat the following infections caused by certain types of worms.

  • An infection called schistosomiasis, which is caused by worms known as blood flukes
  • An infection caused by certain worms known as liver flukes

Praziquantel may also be used for other conditions as determined by your healthcare provider.

How does praziquantel work (mechanism of action)?

Praziquantel kills certain types of worms that cause infections.

How is praziquantel supplied (dosage forms)?

Brands and other names

  • Biltricide

Dosage forms and strengths

  • 600 mg oral tablets

How should I store praziquantel?

Praziquantel should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of praziquantel?

The most common side effects of praziquantel are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • General feeling of being unwell, tired, or not having your usual energy
  • Headache
  • Dizziness
  • Stomach discomfort and nausea
  • Fever
  • Hives

There may be other side effects of praziquantel that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of praziquantel?

While less common, the most serious side effects of praziquantel are described below, along with what to do if they happen.

Severe Allergic Reactions. Praziquantel may cause allergic reactions, which can be serious. Stop taking praziquantel and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Worsened Condition. When you start taking praziquantel to treat a worm infection, your immune system might react to the dying worms, causing you to feel sicker than before. This reaction can be serious and may lead to death. This is more likely to happen in people with an infection caused by a blood fluke, known as schistosomiasis. Get emergency help right away if you have any of the following new symptoms, or if any of your current symptoms get worse.

  • Severe headache
  • Nausea or vomiting
  • Confusion
  • Severe shaking or shivering
  • Weakness or coordination problems
  • Trouble breathing
  • Vision problems

Brain or Central Nervous System (CNS) Problems. Praziquantel can affect your brain or central nervous system (CNS). Call your healthcare provider right away if you develop any of these symptoms of brain or CNS problems.

  • Seizures
  • Severe headache
  • Sluggishness or decreased energy
  • Confusion or disorientation
  • Reduced responses

Abnormal Heart Rhythm. Praziquantel may increase your risk of an abnormal heart rhythm (arrhythmia). Call your healthcare provider or get medical attention right away if you have chest pain, a fast or irregular heartbeat, or if you feel your heartbeat more than usual.

Warnings & Precautions

Who should not use praziquantel?

Allergies to Ingredients. People who are allergic to any of the following should not take praziquantel.

  • Biltricide
  • Praziquantel
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific praziquantel products they stock.

Drug Interactions. Praziquantel should not be taken while you are using certain other medicines. Before taking praziquantel, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.  See the Interactions section for more details.

Worm Infection in the Eye. People who have a worm infection in the eye should not take praziquantel. Talk to your healthcare provider about having an eye exam before taking praziquantel.

What should I know about praziquantel before using it?

Do not take praziquantel unless it has been prescribed to you by a healthcare provider. Take it as prescribed. Each dose of praziquantel should be taken at least four to six hours apart.

Do not share praziquantel with other people, even if they have the same condition as you. It may harm them.

Keep praziquantel out of the reach of children.

Praziquantel can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination while you are taking praziquantel or on the day after stopping praziquantel.

Do not chew praziquantel or hold the tablet in the mouth for any length of time. Take each dose with a meal and a glass of water. If you or your child are not able to swallow the tablet whole, it may be crushed and mixed with a liquid or a soft food like applesauce. Once the tablet has been crushed, it must be taken within one hour.

Keep all follow up-appointments. Your healthcare provider may need to check to make sure that your infection is gone. 

What should I tell my healthcare provider before using praziquantel?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if praziquantel is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Eye or vision problems
  • Heart problems, including abnormal heart rhythm (arrhythmia)
  • Liver problems
  • Seizures or epilepsy

Pregnancy. It is not known if or how praziquantel could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take praziquantel while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if praziquantel passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does praziquantel interact with foods or drinks?

Praziquantel should be taken with a meal and a glass of water. You should not eat grapefruit or drink grapefruit juice while taking praziquantel.

It is unknown if drinking alcohol will affect praziquantel, but heavy drinking can slow your immune response and make it harder for your body to fight infection.

Does praziquantel interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

 In particular, make sure that you discuss if you are using any of the following before taking praziquantel.

  • A medicine for HIV or AIDS
  • Cimetidine (Tagamet HB), which is a medicine used for heartburn
  • Erythromycin (Ery-Tab and others), which is a medicine used for bacterial infections
  • Ketoconazole, itraconazole (Sporanox, Tolsura), posaconazole (Noxafil), fluconazole (Diflucan), or voriconazole (Vfend), which is a medicine used for fungal infections
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis

Many other medicines may alter the blood levels of praziquantel. Tell your healthcare provider about all medicines that you take or have recently taken. 

This may not be a complete list of medicines that can interact with praziquantel. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much praziquantel?

If you or someone else has used too much praziquantel, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of praziquantel?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.