Praziquantel (Oral)

When someone has unknowingly ingested Schistosoma worms from bad water, a medication such as praziquantel is needed to treat the resulting infection and larval growth of the worms.


It is fairly common in some under-developed countries of the world for people to drink from contaminated water sources, or to ingest fish which have been infested with worms. Once these enter the body, they can cause all kinds of problems, including various infections, and must be eliminated at the earliest juncture possible.

Praziquantel prevents any of the newly hatched larvae of these worms from multiplying and growing inside the body, where they could cause tremendous damage. Just by coming into contact with contaminated water, for instance through the skin, a person can become infected with Schistosoma worms, and become seriously ill due to the infection which will likely develop.

This kind of infection commonly occurs in South American countries, the Caribbean, parts of Asia and Africa, where less than hygienic conditions may prevail. Another method of entry that worms might have for entering a human body is through contaminated fish that contain liver flukes, which are worms mostly found in eastern Asia.

These kinds of parasites become paralyzed or killed off entirely when praziquantel is administered to an infected patient. Once the parasites are paralyzed, it forces them to release their hold on the wall of a blood vessel, after which they can easily be removed by the body's natural processes. As soon as their parasitic influence is destroyed, a patient will typically return to good health very quickly.

Condition treated

  • Infections caused by Schistosoma worms

Type Of Medicine

  • Anthelmintic (anti-worm medication)

Side Effects

Besides the expected effects of killing off parasites infecting the body, praziquantel may also trigger some unwanted side effects in patients as well. Of these, perhaps the most serious is an allergic reaction to the drug, since the symptoms caused by an allergic reaction can become severe enough to be life-threatening in some situations. Be sure to tell your doctor ahead of time if you know you are allergic to praziquantel or any of the ingredients used to make it. You should also let your doctor know if you have any other kinds of allergic reactions to fabrics, foods, preservatives, or pets because certain inactive components of praziquantel may actually trigger your other allergies and cause serious reactions. If you suspect that you may be allergic to praziquantel, here are the symptoms to look for:

  • Extreme itchiness at various locations around the body
  • Hives and/or rashes which appear on the skin
  • Difficulty with breathing, often accompanied by chest tightness
  • Disorientation or dizziness, with the sensation that you might pass out
  • Very noticeable swelling in the facial area, usually most concentrated in the lips, tongue, and throat.

There are a number of side effects which may become apparent after taking praziquantel, as you feel the impact of the drug killing off parasites and the parasitic infection. These symptoms are generally mild in nature and do not usually worsen with the passage of time, but if any of them do appear and make you feel uncomfortable, you should contact your doctor immediately and relate whatever symptoms you are experiencing.

The known milder effects of using praziquantel include the following:

  • Unusual weakness
  • Loss of appetite
  • Muscle and/or joint pain
  • Nausea and/or vomiting
  • Stomach or abdominal pain
  • Persistent headaches
  • Dizziness or lightheadedness
  • Profuse sweating.

There are a few side effects which are uncommon in patients using praziquantel, but they are serious enough that if you should experience any of these, you should seek medical attention as soon as possible:

  • Bloody diarrhea
  • Seizures or convulsions
  • Irregular or slow heartbeat
  • Fever with or without chills.

Another class of side effects which are considered moderate to severe in nature are the following, and if you should experience any of these, it is recommended that you tell your doctor about them at the next visit, or as soon as possible.

  • Wheezing
  • Unusual tiredness
  • Unexplained bruising or bleeding
  • Swollen glands in the neck
  • Unexplained swelling of the lips, hands, feet, eyelids, or face
  • Shortness of breath
  • Sore throat
  • Redness on the skin
  • Chills and fever
  • Dizziness with the possibility of fainting
  • Hoarseness
  • Stiffness, swelling, or pain in the joints
  • Stomach discomfort or abdominal discomfort, possibly accompanied by nausea
  • Black tarry stools
  • Chest pains
  • White spots, ulcers, or sores appearing around the mouth or on the lips
  • Difficulty urinating or painful urination.


For most variations of Schistosoma parasites, an adult dosage might begin with 60 mg per kg of weight each day. This would be taken in either two or three equally divided dosages orally. It is generally not necessary to continue treatment with praziquantel after a single day's total dosage, but if it is determined that parasites still exist in the patient, a re-treatment can be administered as soon as two weeks after the initial dosage.

It should be borne in mind that there are several types of Schistosoma parasite, and treatment of each of these may call for a slightly greater or slightly lesser dosage, but in virtually all cases of Schistosoma parasite, the preferred medication is praziquantel.

When treating an adult for liver flukes, which come from contaminated fish, a standard initial dosage of praziquantel would consist of 75 mg per kilogram of weight in a single day of treatment. This would generally be divided into three equal dosages over the course of the 24 hours. Even though there are several types of liver flukes, praziquantel is still considered the most effective drug for killing off this parasite and reducing infection in the patient.

An adult dosage of praziquantel when dealing with either fish tapeworm, beef tapeworm, pork tapeworm or dog tapeworm parasites would consist of a standard initial dosage of between five and 10 mg per kilogram of weight, taken orally in a single day.

For child patients who have been infected with Schistosoma parasites, and are at least four years old or above, a standard initial dosage would be 60 mg per kilogram of weight in one day, generally divided into three equal dosages over 24 hours. As with adults, if a single day's dosage has not completely eliminated the parasitic colony, a re-treatment can be administered within two weeks of the initial dosage.

A pediatric dosage for the treatment of liver flukes, in children at least four years old and older would consist of 75 mg per kilogram of weight in a single day, taken orally and equally divided over three dosages within the 24 hour period.


Because there is a potential for praziquantel to interact with other medications you may be taking, it is necessary to have a full review of all other drugs you are using currently with your doctor. This will help to avoid any serious side effects which might occur as a result of interactions between drugs, and something which should be taken very seriously by both doctor and patient.

To facilitate this process, you should prepare a full list of all other prescription medications which are currently using, as well as all vitamins, herbal supplements, and over-the-counter drugs which you are taking, in addition to the precise dosages of each of these. The same list can be used when you have to go to the emergency room or some other healthcare clinic where your primary care doctor is not in residence. Any doctor who is fully aware of the medications you are taking will be able to safely prescribe treatment for any condition which brings you into an emergency room.

Some of the medications which are known to have at least a moderate interaction with praziquantel are the following:

  • Azole antifungals such as ketoconazole and itraconazole
  • Chloroquine
  • Dexamethasone
  • St. John's Wort
  • Cimetidine
  • Macrolide antibiotics such as erythromycin
  • Rifampin
  • Carbamazepine
  • Primidone
  • Phenytoin
  • Phenobarbital
  • Acetylsalicylic acid
  • Vitamin K
  • Vitamin K1
  • Zinc
  • Vitamin A
  • Vitamin D
  • Vitamin B complex 100
  • Vitamin B6
  • Vitamin B12
  • Vitamin C
  • Bactrim
  • Valproate sodium
  • Penicillin G procaine
  • Paracetamol
  • Levaquin
  • Baricon
  • Viagra
  • Benadryl
  • Elavil
  • Dermatop.


There are a number of precautions and warnings which need to be taken into account by all patients considering treatment with praziquantel. In some cases, these warnings concern your own medical history or diseases which you may presently have, because this medication may cause some kind of negative reaction with them. In other cases, the precautions relate to side effects the drug may impart to you after ingestion, which may inhibit your ability to perform tasks requiring concentration. In any case, all precautions and warnings issued for patients using praziquantel should be seriously considered and discussed with your family doctor before taking the drug.

The first and most serious precaution relates to being allergic to praziquantel “ if you know you are allergic to the medication or any of the ingredients used in its manufacture, you should definitely not take this drug and should alert your doctor to the existing allergy.

You should not take praziquantel if you have a parasitic eye infection, also known as ocular cysticercosis. If you have a medical history of liver disease or an enlarged spleen, you should not take praziquantel. You should also avoid taking the drug if you have any kind of history of heart disease or irregular heartbeat, parasitic brain infection and seizures or convulsions.

Praziquantel is known to make some patients extremely drowsy or dizzy after ingestion, so it is highly inadvisable to operate any machinery in the immediate aftermath of taking this drug, nor should you attempt to operate a motor vehicle. Even though you may start out feeling alert and refreshed, within a few minutes you may experience extreme drowsiness and become a very large danger to yourself and to others. For the same reason, you should not drink alcohol or smoke marijuana after having taken praziquantel, because both of these will deepen the effects of any drowsiness or dizziness which may be experienced as a result of the drug itself.

There are no known animal studies which point out the fact of problems passed on to infants by mothers who are taking praziquantel. Still, it is considered inadvisable to become pregnant at the same time as taking this medication, because it cannot be known for certain whether any negative impact will be sustained by the fetus.

It is known that praziquantel is passed on through breast milk to an infant, so it is highly recommended that new mothers avoid breastfeeding in the timeframe where they are being treated with praziquantel. At the very least, it is strongly recommended that breastfeeding be discontinued on the day of treatment with praziquantel and for at least three days afterwards. During this timeframe, all breastmilk should be simply pumped and discarded as unusable.


This medication should be stored away from direct light in a room where the temperature does not exceed 86 degrees Fahrenheit, and it should never be frozen. The location where it is stored should not be subject to high humidity, as a bathroom might be during episodes of showering or bathing by household members. Praziquantel should be kept away from all pets and youngsters to avoid the possibility of accidental ingestion. It should not be kept in any kind of pill reminder container because very few of these have any kind of locking mechanism which can keep the contents secure against unwanted access.

When praziquantel has expired, it should be discarded rather than used after expiration. Do not flush this medication down a sink drain or down the toilet, but ensure that proper disposal methods are used instead. If you are unsure of how to properly discard unused praziquantel, consult your doctor or pharmacist. Lacking this information, you can consult a website maintained by the FDA for the safe disposal of medicines.


Praziquantel is the preferred medication used by doctors to rid patients of parasitic worms which invade the body by various means. In some cases, these parasites enter the body through unclean water, and in other cases through contaminated fish or meats. The most common occurrences of these kinds of parasitic infections are in under-developed nations where good hygiene and health standards may not always be practised.

It is generally only necessary to be treated with praziquantel over the course of a single day since it is highly effective at killing the parasites which have entered the human host. The drug will very quickly either paralyze or kill the worms completely. When paralyzed only, they will be forced to release any hold they might have on internal areas, and will then be flushed out of the body by normal processes. All parasites which are killed will be removed by the same natural processes, and the body will quickly re-establish normal, healthy status.

There are relatively few side effects associated with taking praziquantel, and also only a few interactions with other drugs, these are both reasons why it is such a popular choice for the removal of parasites and for fighting any infection they may have instigated. Both adult and child patients can take this medication with a high degree of tolerance, and a high degree of effectiveness.