Biltricide Side Effects

Generic Name: praziquantel

Note: This document contains side effect information about praziquantel. Some of the dosage forms listed on this page may not apply to the brand name Biltricide.

Some side effects of Biltricide may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to praziquantel: oral tablet

Along with its needed effects, praziquantel (the active ingredient contained in Biltricide) 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 while taking praziquantel:

Incidence not known
  • Abdominal or stomach discomfort with or without nausea
  • abdominal or stomach pain
  • black, tarry stools
  • bloody diarrhea
  • chest pain or discomfort
  • chills
  • convulsions
  • cough
  • dizziness
  • fainting
  • fast, slow, or irregular heartbeat
  • fever
  • hives
  • hoarseness
  • irritation
  • itching
  • joint pain, stiffness, or swelling
  • lightheadedness, dizziness, or fainting
  • painful or difficult urination
  • rash
  • redness of the skin
  • severe abdominal or stomach pain
  • shortness of breath
  • slow or irregular heartbeat
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sweating
  • swelling of the eyelids, face, lips, hands, or feet
  • swollen glands
  • tightness in the chest
  • troubled breathing or swallowing
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • wheezing

Some side effects of praziquantel 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
  • Drowsiness
  • increased sweating
  • general feeling of discomfort or illness
  • nausea or vomiting
Less common
  • Skin rash, hives, or itching
Incidence not known
  • Difficulty with moving
  • dizziness or lightheadedness
  • feeling of constant movement of self or surroundings
  • headache
  • hives or welts
  • joint pain
  • lack or loss of strength
  • loss of appetite
  • muscle aching or cramping
  • muscle pains or stiffness
  • redness of the skin
  • sensation of spinning
  • sleepiness or unusual drowsiness
  • swollen joints
  • weight loss

For Healthcare Professionals

Applies to praziquantel: compounding powder, oral tablet


Praziquantel (the active ingredient contained in Biltricide) is generally well tolerated. Side effects are typically mild and transient and do not require treatment. The following were observed generally in order of severity: malaise, headache, dizziness, abdominal discomfort (with or without nausea), rise in temperature and, rarely, urticaria. Such symptoms can, however, also result from the infection itself. Such side effects may be more frequent and/or serious in patients with a heavy worm burden.

Nervous system

The inflammatory reaction produced by antigenic substances released from dying cysts frequently involves increased intracranial pressure, seizures, severe headaches, nausea, and vomiting. In areas where Taenia solium is endemic, these reactions may occur as the result of undiagnosed cysticercosis in patients being treated for other parasitic infections. Corticosteroids are helpful in controlling this reaction, and the dosage needs to be tailored to the patient's individual needs. Corticosteroids may need to be continued past praziquantel (the active ingredient contained in Biltricide) therapy, as the duration of the reaction differs among patients. Delayed reactions have been reported.

Nervous system side effects have included headache, dizziness, and drowsiness. The treatment of neurocysticercosis with praziquantel may precipitate a cerebral inflammatory reaction in response to antigenic substances produced by dying cysts. Convulsion, somnolence, and vertigo have been reported during postmarketing experience.


Gastrointestinal side effects have included abdominal discomfort (with or without nausea), nausea and diarrhea. A syndrome of severe abdominal pain and bloody diarrhea was reported less frequently during the treatment of schistosomiasis. Gagging and vomiting have been reported due to the bitter taste of the tablets. Abdominal pain, anorexia, bloody diarrhea, and vomiting have been reported during postmarketing experience.


Other side effects have included malaise, rise in temperature, transient edema, and fever. Asthenia has been reported during postmarketing experience.


Musculoskeletal side effects have included musculoskeletal aches and fatigue. Myalgia has been reported during postmarketing experience.


Dermatologic side effects have included urticaria. At least one case of Mazzotti-like reaction has been reported. Pruritus has been reported during postmarketing experience.

A 13-year-old male developed Mazzotti reaction after treatment with ivermectin, praziquantel, and albendazole for presumptive schistosomiasis and strongyloidiasis. Six days after receiving standard empiric therapy, he developed epigastric pain, vomiting, and urticaria. This progressed in 4 hours and included fever, general myalgia and edema of the face, lower extremities and penis accompanied by urticaria of the arms, legs, and trunk. He was diagnosed with a Mazzotti reaction and treated with methylprednisolone and the symptoms subsided within 12 hours.


Hepatic side effects have included minimal increases in liver enzymes.


Cardiovascular side effects have included arrhythmia (including bradycardia, ectopic rhythms, ventricular fibrillation, atrioventricular blocks) during postmarketing experience.


Hematologic side effects have included eosinophilia during postmarketing experience.


Hypersensitivity side effects have included allergic reaction (generalized hypersensitivity) including polyserositis during postmarketing experience.

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