Last updated on RxList: 3/20/2023

Drug Summary

What Is Biltricide?

Biltricide (praziquantel) is an anthelmintic, or anti-worm, medication used to treat infections caused by Schistosoma worms, which enter the body through skin that has come into contact with contaminated water. Schistosoma worms are found in Africa, South America, Middle Eastern countries, the Caribbean, and parts of Asia. Biltricide is also used to treat infection with liver flukes, caused by a type of worm found in East Asia.

What Are Side Effects of Biltricide?

Biltricide may cause serious side effects including:

  • hives,
  • difficulty breathing,
  • swelling of your face, lips, tongue, or throat,
  • fever,
  • chills,
  • sore throat,
  • headache,
  • body aches,
  • tiredness,
  • not feeling well,
  • slow or irregular heartbeats,
  • stomach cramps,
  • bloating,
  • diarrhea,
  • constipation,
  • nausea,
  • seizure,
  • trouble concentrating,
  • cold sweats, and
  • skin irritation

Get medical help right away, if you have any of the symptoms listed above.

Common side effects of Biltricide include:

  • headache,
  • dizziness,
  • stomach pain or upset,
  • nausea,
  • tiredness,
  • weakness,
  • joint or muscle pain,
  • loss of appetite,
  • vomiting,
  • fever,
  • skin rash, and
  • sweating.

Side effects of Biltricide are usually mild and temporary and may be symptoms of the parasite infection and/or the dying parasites.

Tell your doctor if you have rare but very serious side effects of Biltricide including:

  • bloody diarrhea,
  • fever,
  • irregular or slow heartbeat, or
  • seizures.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Biltricide

The recommended dosage of Biltricide for the treatment of schistosomiasis is 20 mg/kg three times a day as a one day treatment, at intervals of 4 to 6 hours. The recommended dose for clonorchiasis and opisthorchiasis is 25 mg/kg three times a day as a one day treatment, at intervals of 4 to 6 hours.

What Drugs, Substances, or Supplements Interact with Biltricide?

Biltricide may interact with cimetidine, chloroquine, itraconazole or ketoconazole, dexamethasone, erythromycin, St. John's wort, rifabutin or rifapentine, barbiturates, HIV medications, medicines to treat narcolepsy, or seizure medications. Tell your doctor all medications you use.

Biltricide During Pregnancy or Breastfeeding

During pregnancy, Biltricide should be used only when prescribed. This drug passes into breast milk. Breastfeeding while using this drug is not recommended. Nursing mothers should stop breastfeeding on the day of treatment and for 72 hours after taking the last dose.

Additional Information

Our Biltricide (praziquantel) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Drug Description


BILTRICIDE® (praziquantel) is a trematodicide provided in tablet form for the oral treatment of schistosome infections and infections due to liver fluke.

BILTRICIDE (praziquantel) is 2-(cyclohexylcarbonyl)-1,2,3,6,7, 11b-hexahydro-4H-pyrazino [2, 1-a] isoquinolin-4-one with the molecular formula; C19H24N2O2. The structural formula is as follows:

BILTRICIDE® (praziquantel)  Structural Formula Illustration

Praziquantel is a white to nearly white crystalline powder of bitter taste. The compound is stable under normal conditions and melts at 136-140°C with decomposition. The active substance is hygroscopic. Praziquantel is easily soluble in chloroform and dimethylsulfoxide, soluble in ethanol and very slightly soluble in water.

BILTRICIDE tablets contain 600 mg of praziquantel. Inactive ingredients: corn starch, magnesium stearate, microcrystalline cellulose, povidone, sodium lauryl sulfate, polyethylene glycol, titanium dioxide and hypromellose.

Indications & Dosage


BILTRICIDE (praziquantel) is indicated for the treatment of infections due to: all species of schistosoma (for example, Schistosoma mekongi, Schistosoma japonicum, Schistosoma mansoni and Schistosoma hematobium), and infections due to the liver flukes, Clonorchis sinensis/Opisthorchis viverrini (approval of this indication was based on studies in which the two species were not differentiated).


The dosage recommended for the treatment of schistosomiasis is: 20 mg/kg bodyweight three times a day as a one day treatment, at intervals of not less than 4 hours and not more than 6 hours. The recommended dose for clonorchiasis and opisthorchiasis is: 25 mg/kg bodyweight three times a day as a one day treatment, at intervals of not less than 4 hours and not more than 6 hours. The tablets should be washed down unchewed with water during meals. Keeping the tablets or segments thereof in the mouth can reveal a bitter taste which can promote gagging or vomiting.


BILTRICIDE (praziquantel) is supplied as a 600 mg white to orange tinged, film-coated, oblong tablet with three scores. The tablet is coded with “BAYER” on one side and “LG” on the reverse side. When broken, each of the four segments contains 150 mg of active ingredient so that the dosage can be easily adjusted to the patient's bodyweight.

Segments are broken off by pressing the score (notch) with thumbnails. If ¼ of a tablet is required, this is best achieved by breaking the segment from the outer end.

BILTRICIDE (praziquantel) is available in bottles of 6 tablets.

  Strength NDC
Bottles of 6 600 mg 0085-1747-01

Store below 86°F (30°C).

Manufactured by: Bayer HealthCare Pharmaceuticals Inc. Wayne, NJ 07470. Made in Germany. Distributed and Marketed by: Schering Corporation, a subsidiary of Whitehouse Station, NJ 08889, USA. Revised: 08/10.

Side Effects


Adverse Events

In general BILTRICIDE (praziquantel) is very well tolerated. Side effects are usually mild and transient and do not require treatment. The following side effects 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.

Post Marketing Adverse Event Reports

Additional adverse events reported from worldwide post marketing experience and from publications with praziquantel include: abdominal pain, allergic reaction (generalized hypersensitivity) including polyserositis, anorexia, arrhythmia (including bradycardia, ectopic rhythms, ventricular fibrillation, AV blocks), asthenia, bloody diarrhea, convulsion, eosinophilia, myalgia, pruritis, somnolence, vertigo and vomiting.

Drug Interactions


Concomitant administration of rifampin, a strong P450 inducer, with praziquantel is contraindicated and must be avoided (see CONTRAINDICATIONS). In a crossover study with a 2-week washout period, 10 healthy subjects ingested a single 40 mg/kg dose of praziquantel following pre-treatment with oral rifampin (600 mg daily for 5 days). Plasma praziquantel concentrations were undetectable in 7 out of 10 subjects. When a single 40 mg/kg dose of praziquantel was administered to these healthy subjects two weeks after discontinuation of rifampin, the mean praziquantel AUC and Cmax were 23% and 35% lower, respectively, than when praziquantel was given alone. In patients receiving rifampin, for example, as part of a combination regimen for the treatment of tuberculosis, alternative agents for schistosomiasis should be considered. However, if treatment with praziquantel is necessary, treatment with rifampin should be discontinued 4 weeks before administration of praziquantel. Treatment with rifampin can then be restarted one day after completion of praziquantel treatment.

Concomitant administration of other drugs that increase the activity of drug metabolizing liver enzymes (P450 inducers), for example, antiepileptic drugs (phenytoin, phenobarbital and carbamazepine), and dexamethasone, may also reduce plasma levels of praziquantel. Concomitant administration of drugs that decrease the activity of drug metabolizing liver enzymes (P 450 inhibitors), for example, cimetidine, ketoconazole, itraconazole, erythromycin may increase plasma levels of praziquantel.

Chloroquine, when taken simultaneously, may lead to lower concentrations of praziquantel in blood. The mechanism of this drug-drug interaction is unclear.

Grapefruit juice was reported to produce a 1.6-fold increase in the Cmax and a 1.9-fold increase in the AUC of praziquantel. However, the effect of this exposure increase on the therapeutic effect and safety of praziquantel has not been systematically evaluated.

Warnings & Precautions


Therapeutically effective levels of BILTRICIDE (praziquantel) may not be achieved when administered concomitantly with strong P450 inducers, such as rifampin (see CONTRAINDICATIONS).



Approximately 80% of a dose of praziquantel is excreted in the kidneys, almost exclusively ( > 99%) in the form of metabolites. Excretion might be delayed in patients with impaired renal function, but accumulation of unchanged drug would not be expected. Therefore, dose adjustment for renal impairment is not considered necessary. Nephrotoxic effects of praziquantel or its metabolites are not known.

Caution should be exercised in the administration of the usual recommended dose of praziquantel to hepatosplenic schistosomiasis patients with moderate to severe liver impairment (Child-Pugh class B and C). Reduced metabolism of praziquantel by the liver in these patients may lead to considerably higher and longer lasting plasma concentrations of unmetabolized praziquantel (See CLINICAL PHARMACOLOGY/Special Populations).

Minimal increases in liver enzymes have been reported in some patients.

Patients suffering from cardiac irregularities should be monitored during treatment.

As BILTRICIDE (praziquantel) can exacerbate central nervous system pathology due to schistosomiasis, as a general rule this drug should not be administered to individuals reporting a history of epilepsy and/or other signs of potential central nervous systems involvement such as subcutaneous nodules suggestive of cysticercosis.

When schistosomiasis or fluke infection is found to be associated with cerebral cysticercosis it is advised to hospitalize the patient for the duration of treatment.

Mutagenesis, Carcinogenesis

Mutagenic effects in Salmonella tests found by one laboratory have not been confirmed in the same tested strain by other laboratories. Long term carcinogenicity studies in rats and golden hamsters did not reveal any carcinogenic effect.

Pregnancy Category B

Reproduction studies have been performed in rats and rabbits at doses up to 40 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to praziquantel. There are, however, no adequate and well-controlled studies in pregnant women. An increase of the abortion rate was found in rats at three times the single human therapeutic dose. While animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Nursing mothers

Praziquantel appeared in the milk of nursing women at a concentration of about 1/4 that of maternal serum although it is not known whether a pharmacological effect is likely to occur in children. Women should not nurse on the day of BILTRICIDE (praziquantel) treatment and during the subsequent 72 hours.

Pediatric use

Safety in children under 4 years of age has not been established.

Geriatric use

Clinical studies of praziquantel did not include a sufficient number of subjects ages 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older patients cannot be ruled out.

This drug is known to be substantially excreted by the kidney. Because elderly patients are more likely to have decreased renal function, the risk of toxic reactions to this drug may be greater in these patients.

Overdose & Contraindications


In rats and mice the acute LD50 was about 2,500 mg/kg. No data are available in humans. In the event of overdose a fast-acting laxative should be given.


BILTRICIDE (praziquantel) is contraindicated in patients who previously have shown hypersensitivity to the drug or any of the excipients. Since parasite destruction within the eye may cause irreversible lesions, ocular cysticercosis must not be treated with this compound.

Concomitant administration with strong Cytochrome P450 (P450) inducers, such as rifampin, is contraindicated since therapeutically effective blood levels of praziquantel may not be achieved (see PRECAUTIONS: DRUG INTERACTIONS). In patients receiving rifampin who need immediate treatment for schistosomiasis, alternative agents for schistosomiasis should be considered. However, if treatment with praziquantel is necessary, rifampin should be discontinued 4 weeks before administration of praziquantel. Treatment with rifampin can then be restarted one day after completion of praziquantel treatment (see PRECAUTIONS: DRUG INTERACTIONS).

Clinical Pharmacology


Praziquantel induces a rapid contraction of schistosomes by a specific effect on the permeability of the cell membrane. The drug further causes vacuolization and disintegration of the schistosome tegument.

After oral administration BILTRICIDE (praziquantel) is rapidly absorbed (80%), subjected to a first pass effect, metabolized and eliminated by the kidneys. Maximal serum concentration is achieved 1-3 hours after dosing. The half-life of praziquantel in serum is 0.8-1.5 hours.

Special Populations

The pharmacokinetics of praziquantel were studied in 40 patients with Schistosoma mansoni infections with varying degrees of hepatic dysfunction (See table 1). In patients with schistosomiasis, the pharmacokinetic parameters did not differ significantly between those with normal hepatic function (Group 1) and those with mild (Child-Pugh class A) hepatic impairment. However, in patients with moderate-to-severe hepatic dysfunction (Child-Pugh class B and C), praziquantel half-life, Cmax, and AUC increased progressively with the degree of hepatic impairment. In Child-Pugh class B, the increases in mean half-life, Cmax, and AUC relative to Group 1 were 1.58-fold, 1.76-fold, and 3.55-fold, respectively. The corresponding increases in Child-Pugh class C patients were 2.82-fold, 4.29-fold, and 15-fold for half-life, Cmax, and AUC.

Table 1: Pharmacokinetic parameters of praziquantel in four groups of patients with varying degrees of liver function following administration of 40 mg/kg under fasting conditions.

Patient Group Half-life (hr) Tmax (hr) Cmax (μg/mL) AUC (μg/mL* hr)
Normal hepatic function (Group 1) 2.99 ± 1.28 1.48 ±0.74 0.83 ± 0.52 3.02 ±0.59
Child-Pugh A (Group 2) 4.66±2.77 1.37 ± 0.61 0.93± 0.58 3.87 ±2.44
Child-Pugh B (Group 3) 4.74 ±2.16a 2.21 ± 0.78a,b 1.47 ±0.74a,b 10.72 ±5.53a,b
Child-Pugh C (Group 4) 8.45 ±2.62a,b,c 3.2 ± 1.05a,b,c 3.57 ±1.30a,b,c 45.35 ± 17.50a,b,c
a) p < 0.05 compared to Group 1
b) p < 0.05 compared to Group 2
c) p < 0.05 compared to Group 3

Medication Guide


Patients should be warned not to drive a car and not to operate machinery on the day of BILTRICIDE (praziquantel) treatment and the following day.

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