Praziquantel is an oral anthelmintic antiparasitic agent. Specifically, it is a trematodicide used to treat infections due to all species of Schistosoma (schistosomiasis) and the liver flukes Clonorchis sinensis (clonorchiasis) and Opisthorchis viverrini (opisthorchiasis). The drug is also effective against several other trematodes (flukes) including Paragonimus westermani. Praziquantel is also used as an alternative for treating cestode (tapeworm) infections due to Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and in combination with benzimidazole drugs (e.g., albendazole) for hydatid cyst disease (larval stage of Echinococcus granulosus). Praziquantel is an alternative to albendazole for cysticercosis (larval stage T. solium infection). However, praziquantel appears more likely to cause side effects during cysticercosis treatment and, unlike albendazole, is not used if ocular cysticercosis is present. Most human cases of these parasitic infections in the United States occur in immigrants who were exposed in their countries of origin, or in US travelers visiting global endemic areas.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
Oral Solid Formulations
-Take tablets orally with liquid during meals (food).
-Do not chew or hold the tablets in the mouth (bitter taste may cause gagging or vomiting).
-To prevent choking in pediatric patients younger than 6 years of age, tablets may be crushed or disintegrated and mixed with semi-solid food or liquid. Use crushed or disintegrated tablets within 1 hour of mixing.
-Tablets are scored for cutting in half or one-fourth if dosage requires. Press the score with the thumbnails. If a quarter (one-fourth) of a tablet is required, this is best achieved by breaking the segment from the outer end.
Praziquantel is generally well tolerated. Adverse effects are generally mild and generally do not require treatment. In order of frequency of occurrence, common side effects include malaise, headache, dizziness, abdominal discomfort with or without nausea, fever, and urticaria. All side effects can also be a result of the underlying parasitic infection, and such symptoms may be more severe in patients with heavy parasitic burden or with cysticercosis. Rarely, the drug can cause elevated hepatic enzymes, but the elevations are of low magnitude. Post-marketing adverse reactions reported from worldwide post marketing experience and from publications with praziquantel include abdominal pain, allergic reactions (generalized hypersensitivity) including polyserositis, anorexia, arrhythmia exacerbation (including sinus bradycardia, ectopic rhythms, ventricular fibrillation, AV block), asthenia (weakness), bloody diarrhea, convulsion (seizures), eosinophilia, fatigue, pruritus, rash (unspecified), myalgia, somnolence (drowsiness), vertigo, and vomiting.
Praziquantel is contraindicated in patients with previous praziquantel hypersensitivity or hypersensitivity to any component of the formulation.
Because parasite destruction within the eye may cause irreparable lesions, praziquantel is contraindicated for use in patients with ocular cysticercosis. Praziquantel can exacerbate CNS pathology due to schistosomiasis; avoid use in patients with a history of epilepsy (seizure disorder) and/or other signs of CNS 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 praziquantel treatment. Data have shown a potential lack of efficacy for praziquantel during the acute phase of schistosomiasis, with the drug not preventing progression from asymptomatic infection to acute schistosomiasis, or from asymptomatic infection/acute schistosomiasis into the chronic phase. In addition, use of the drug, predominately during acute schistosomiasis, may be associated with clinical deterioration (e.g., paradoxical reactions, serum sickness, Jarisch-Herxheimer like reactions) that can lead to life-threatening events (respiratory failure, encephalopathy, papilledema, and/or cerebral vasculitis).
Praziquantel should be used with caution in patients with hepatic disease, as reduced hepatic metabolism of praziquantel may result in significantly higher and longer lasting plasma concentrations of unmetabolized praziquantel. Monitor hepatosplenic schistosomiasis patients with moderate or severe hepatic impairment (Child-Pugh B or C) for adverse reactions when administering praziquantel.
Patients with or who have a history of cardiac irregularities should be monitored during treatment with praziquantel. Praziquantel has been associated with cardiac arrhythmias, including AV block, bradycardia, ectopic rhythms, and ventricular fibrillation.
Praziquantel may cause dizziness. Patients should be instructed to avoid driving or operating machinery on the day of praziquantel treatment or the day after treatment.
Published studies, including 2 randomized, controlled studies, have not identified a risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes with praziquantel use during human pregnancy. For mass prevention campaigns, the benefit of praziquantel use outweighs the risk at any stage of pregnancy. For individual patients in a clinical setting, weigh the risk of treatment in pregnancy with the risk of disease progression in the absence of treatment. Guidelines suggest deferring treatment for neurocysticercosis until after pregnancy unless intracranial pressure is elevated.
Praziquantel is excreted in human breast milk. In a study of 10 women, 5 receiving single-dose therapy and 5 receiving 3-dose therapy, the concentration in breast milk is about one-fourth (25%) that of maternal serum concentration or 0.0008% of the given dose. Breast milk concentrations were undetectable 24 to 32 hours after exposure. There are no data available on the effects of praziquantel on the breastfed infant or milk production. A consultation group to the World Health Organization (WHO) states that single dose-therapy may be administered to breast-feeding women. Alternatively, to reduce exposure in the breast-feeding infant, an alternate feeding method (e.g., stored milk) may be used for 24 to 36 hours after therapy. For mass prevention campaigns, praziquantel use is encouraged during breast-feeding. For individual patients in a clinical setting, weigh the risk of treatment with the risk to the infant and the risk of disease progression in the mother in the absence of treatment.
Per the manufacturer, this drug has been shown to be active against most strains of the following microorganisms either in vitro and/or in clinical infections: Clonorchis sinensis, Opisthorchis viverrini, Schistosoma hematobium, Schistosoma japonicum, Schistosoma mansoni, Schistosoma mekongi
NOTE: The safety and effectiveness in treating clinical infections due to organisms with in vitro data only have not been established in adequate and well-controlled clinical trials.
This drug may also have activity against the following microorganisms: Echinococcus granulosus, Fasciolopsis buski, Heterophyes heterophyes, Metagonimus yokogawai, Nanophytetus salmincola, Paragonimus westermani, Taenia saginata, Taenia solium
NOTE: Some organisms may not have been adequately studied during clinical trials; therefore, exclusion from this list does not necessarily negate the drug's activity against the organism.
For the treatment of schistosomiasis:
-for the treatment of schistosomiasis due to S. japonicum and S. mekongi:
Oral dosage:
Adults: 20 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
Children and Adolescents: 20 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
-for the treatment of schistosomiasis due to S. mansoni, S. haematobium, and S. intercalatum:
Oral dosage:
Adults: 20 mg/kg/dose PO 2 times daily for 1 day. The FDA-approved dose is 20 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
Children and Adolescents: 20 mg/kg/dose PO 2 times daily for 1 day. The FDA-approved dose is 20 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
For the treatment of cysticercosis*:
Oral dosage:
Adults: 50 mg/kg/day PO given in 3 divided doses for 2 to 4 weeks. Surgery is indicated for intraocular cysts; intraocular cysts should be removed before administration of antiparasitic treatment to avoid irreversible eye damage due to the inflammatory response.
Children and Adolescents: 50 mg/kg/day PO given in 3 divided doses for 2 to 4 weeks. Surgery is indicated for intraocular cysts; intraocular cysts should be removed before administration of antiparasitic treatment to avoid irreversible eye damage due to the inflammatory response.
For the treatment of neurocysticercosis*, including parenchymal* and extraparenchymal cysts*:
NOTE: Anticonvulsant therapy is recommended in patients with seizures.
-for the treatment of neurocysticercosis with more than 2 parenchymal cysts*:
Oral dosage:
Adults: 50 mg/kg/day PO in 3 divided doses for 10 to 14 days combined with albendazole and corticosteroids.
Children and Adolescents: 50 mg/kg/day PO in 3 divided doses for 10 to 14 days combined with albendazole and corticosteroids.
-for the treatment of neurocysticercosis with subarachnoid extraparenchymal cysts*:
Oral dosage:
Adults: 50 mg/kg/day PO in 3 divided doses combined with albendazole and corticosteroids. Continue treatment for 2 to 12 months or until resolution of cystic lesions on neuroimaging studies.
Children and Adolescents: 50 mg/kg/day PO in 3 divided doses combined with albendazole and corticosteroids. Continue treatment for 2 to 12 months or until resolution of cystic lesions on neuroimaging studies.
For the treatment of taeniasis* (tapeworm infection*):
Oral dosage:
Adults: 5 to 10 mg/kg/dose PO as a single dose.
Children and Adolescents: 5 to 10 mg/kg/dose PO as a single dose.
For adjunctive treatment of hydatid cyst disease* in combination with albendazole:
NOTE: Praziquantel is not effective as monotherapy for hydatid cyst disease.
Oral dosage:
Adults: 40 mg/kg/dose PO once weekly, or alternately, 40 mg/kg/dose PO once daily in short-term treatment, although this dose was not always tolerated. Praziquantel may be useful preoperatively or in the case of spillage of cyst contents.
For the treatment of clonorchiasis or opisthorchiasis:
Oral dosage:
Adults: 25 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
Children and Adolescents: 25 mg/kg/dose PO 3 times daily for 1 day; separate doses by 4 to 6 hours.
For the treatment of paragonimiasis*:
Oral dosage:
Adults: 25 mg/kg/dose PO 3 times daily for 2 days.
Children and Adolescents: 25 mg/kg/dose PO 3 times daily for 2 days.
Maximum Dosage Limits:
-Adults
75 mg/kg/day PO.
-Geriatric
75 mg/kg/day PO.
-Adolescents
75 mg/kg/day PO.
-Children
75 mg/kg/day PO.
-Infants
Safety and efficacy have not been established.
-Neonates
Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Monitor hepatosplenic patients with moderate to severe hepatic impairment (Child-Pugh class B and C) for adverse reactions when administering praziquantel; reduced metabolism can occur in these patients, resulting in considerably higher and longer lasting plasma concentrations of unmetabolized drug. Specific recommendations regarding dosage adjustment in hepatic impairment are not available.
Patients with Renal Impairment Dosing
Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.
*non-FDA-approved indication
Albendazole: (Moderate) Monitor for albendazole-related adverse effects if concomitant use with praziquantel is necessary. Concomitant use has been observed to increase albendazole overall exposure by approximately 50%.
Amobarbital: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Apalutamide: (Contraindicated) Concomitant use of praziquantel and apalutamide is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and apalutamide is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Aspirin, ASA; Butalbital; Caffeine: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Barbiturates: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Bexarotene: (Major) Avoid concomitant use of praziquantel and bexarotene. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and bexarotene is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Bosentan: (Major) Avoid concomitant use of praziquantel and bosentan. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and bosentan is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Butalbital; Acetaminophen: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Butalbital; Acetaminophen; Caffeine: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Butalbital; Acetaminophen; Caffeine; Codeine: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Butalbital; Aspirin; Caffeine; Codeine: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Carbamazepine: (Contraindicated) Concomitant use of praziquantel and carbamazepine is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and carbamazepine is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Cenobamate: (Major) Avoid concomitant use of praziquantel and cenobamate. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and cenobamate is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Chloroquine: (Minor) Monitor for altered clinical response to praziquantel if concomitant use with chloroquine is necessary. Concomitant use has been observed to decrease praziquantel exposure which may reduce its efficacy.
Cimetidine: (Moderate) Drugs that inhibit hepatic metabolism via the microsomal CYP450 enzyme system, such as cimetidine, may increase the bioavailability of praziquantel.
Dabrafenib: (Major) Avoid concomitant use of praziquantel and dabrafenib. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and dabrafenib is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Efavirenz: (Major) Avoid concomitant use of praziquantel and efavirenz. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and efavirenz is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with efavirenz, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Avoid concomitant use of praziquantel and efavirenz. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and efavirenz is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with efavirenz, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Avoid concomitant use of praziquantel and efavirenz. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and efavirenz is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with efavirenz, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Elagolix: (Major) Avoid concomitant use of praziquantel and elagolix. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and elagolix is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Elagolix; Estradiol; Norethindrone acetate: (Major) Avoid concomitant use of praziquantel and elagolix. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and elagolix is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Encorafenib: (Contraindicated) Concomitant use of praziquantel and encorafenib is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and encorafenib is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Enzalutamide: (Contraindicated) Concomitant use of praziquantel and enzalutamide is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and enzalutamide is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Erythromycin: (Moderate) Erythromycin is a significant CYP3A4 inhibitor and may reduce metabolism of praziquantel. This interaction may be beneficial. The combination may prolong the exposure of the parasites to praziquantel and may not result in an increased risk of side effects.
Eslicarbazepine: (Major) Avoid concomitant use of praziquantel and eslicarbazepine. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and eslicarbazepine is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Etravirine: (Major) Avoid concomitant use of praziquantel and etravirine. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and etravirine is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Flutamide: (Major) In vitro and drug interactions studies suggest that the CYP3A4 isoenzyme is the major enzyme involved in praziquantel metabolism. Therefore, use of praziquantel with flutamide, a CYP3A4 inducer, should be done with caution as concomitant use may produce therapeutically ineffective concentrations of praziquantel.
Fosphenytoin: (Contraindicated) Concomitant use of praziquantel and fosphenytoin is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and fosphenytoin is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Grapefruit juice: (Moderate) Coadministration of grapefruit juice with praziquantel has been reported to increase blood levels and AUC of praziquantel, which may be advantageous in the treatment of various parasitic infections. However, more study is needed to determine if this interaction is beneficial or harmful.
Hydroxychloroquine: (Minor) Monitor for altered clinical response to praziquantel if concomitant use with hydroxychloroquine is necessary. Concomitant use of praziquantel with chloroquine has been observed to reduce praziquantel exposure which may reduce its efficacy. A similar interaction may occur with hydroxychloroquine.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Contraindicated) Concomitant use of praziquantel and rifampin is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and rifampin is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by rifampin resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of rifampin, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Isoniazid, INH; Rifampin: (Contraindicated) Concomitant use of praziquantel and rifampin is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and rifampin is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by rifampin resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of rifampin, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Itraconazole: (Moderate) Itraconazole inhibits CYP3A4 and may reduce metabolism of praziquantel. This interaction may be beneficial. The combination may prolong the exposure of the parasites to praziquantel and may not result in an increased risk of side effects.
Ketoconazole: (Moderate) Ketoconazole inhibits CYP3A4 and may reduce metabolism of praziquantel. This interaction may be beneficial. The combination may prolong the exposure of the parasites to praziquantel and may not result in an increased risk of side effects.
Levoketoconazole: (Moderate) Ketoconazole inhibits CYP3A4 and may reduce metabolism of praziquantel. This interaction may be beneficial. The combination may prolong the exposure of the parasites to praziquantel and may not result in an increased risk of side effects.
Lopinavir; Ritonavir: (Moderate) Monitor for increased side effects of praziquantel if administered with ritonavir. Concurrent administration may result in elevated praziquantel plasma concentrations. Praziquantel is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme.
Lorlatinib: (Major) Avoid concomitant use of praziquantel and lorlatinib. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and lorlatinib is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Lumacaftor; Ivacaftor: (Contraindicated) Concomitant use of praziquantel and lumacaftor; ivacaftor is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and lumacaftor; ivacaftor is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Lumacaftor; Ivacaftor: (Contraindicated) Concomitant use of praziquantel and lumacaftor; ivacaftor is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and lumacaftor; ivacaftor is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Mavacamten: (Major) Avoid concomitant use of praziquantel and mavacamten. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and mavacamten is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Methohexital: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Mitotane: (Contraindicated) Concomitant use of praziquantel and mitotane is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and mitotane is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Nafcillin: (Major) Avoid concomitant use of praziquantel and nafcillin. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and nafcillin is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Nirmatrelvir; Ritonavir: (Moderate) Monitor for increased side effects of praziquantel if administered with ritonavir. Concurrent administration may result in elevated praziquantel plasma concentrations. Praziquantel is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme.
Omeprazole; Amoxicillin; Rifabutin: (Major) Avoid concomitant use of praziquantel and rifabutin. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and rifabutin is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Pentobarbital: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Pexidartinib: (Major) Avoid concomitant use of praziquantel and pexidartinib. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and pexidartinib is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Phenobarbital: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Phenytoin: (Contraindicated) Concomitant use of praziquantel and phenytoin is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and phenytoin is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Primidone: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Repotrectinib: (Major) Avoid concomitant use of praziquantel and repotrectinib. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and repotrectinib is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Rifabutin: (Major) Avoid concomitant use of praziquantel and rifabutin. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and rifabutin is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
Rifampin: (Contraindicated) Concomitant use of praziquantel and rifampin is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and rifampin is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by rifampin resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of rifampin, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Rifapentine: (Contraindicated) Concomitant use of praziquantel and rifapentine is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and rifapentine is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Ritonavir: (Moderate) Monitor for increased side effects of praziquantel if administered with ritonavir. Concurrent administration may result in elevated praziquantel plasma concentrations. Praziquantel is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme.
Secobarbital: (Contraindicated) Concomitant use of praziquantel and barbiturates is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and barbiturates are strong CYP3A inducers. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Sotorasib: (Major) Avoid concomitant use of praziquantel and sotorasib. Concurrent use may decrease praziquantel exposure which may reduce its efficacy. If concomitant use is necessary, monitor for reduced response to praziquantel. Praziquantel is a CYP3A substrate and sotorasib is a moderate CYP3A inducer. When praziquantel was administered after 13 days of treatment with a moderate CYP3A inducer, the mean praziquantel AUC was 77% lower than when praziquantel was given alone.
St. John's Wort, Hypericum perforatum: (Contraindicated) Concomitant use of praziquantel and St. John's wort is contraindicated due to the risk of decreased praziquantel exposure which may reduce its efficacy. Praziquantel is a CYP3A substrate and St. John's wort is a strong CYP3A inducer. In a crossover study with a 2-week washout period, administration of praziquantel followed by another strong CYP3A inducer resulted in undetectable plasma concentrations of praziquantel in 7 out of 10 subjects. When praziquantel was administered 2 weeks after discontinuation of the strong inducer, the mean praziquantel AUC was 23% lower than when praziquantel was given alone.
Praziquantel works by increasing the cell membrane permeability in susceptible worms. This induces a rapid contraction of the schistosomes. Praziquantel further causes vacuolization and disintegration of the schistosome tegument.
Praziquantel is administered orally. It is metabolized by the liver. Approximately 80% of an administered dose is excreted via the kidney almost exclusively (more than 99%) as metabolites. The serum half-life is 0.8 to 1.5 hours.
Affected cytochrome P450 isoenzymes and drug transporters: CYP3A4
In general, drugs that inhibit hepatic metabolism via the microsomal CYP450 enzyme system increase the bioavailability of praziquantel and potent CYP450 enzyme inducers may decrease praziquantel serum concentrations. In vitro and drug interaction studies suggest that praziquantel may be a substrate of CYP3A4. Concomitant strong CYP3A4 inducers are contraindicated, while other CYP3A4 inducers may decrease effectiveness of praziquantel. CYP3A4 inhibitors may not have any clinical implications due to the dosing of praziquantel and the limited side effect profile.
-Route-Specific Pharmacokinetics
Oral Route
Praziquantel is rapidly absorbed and undergoes first-pass metabolism. Bioavailability is approximately 80%. Maximal praziquantel serum concentrations occur within 1 to 3 hours after dosing.
-Special Populations
Hepatic Impairment
Praziquantel pharmacokinetics were evaluated in 40 patients with Schistosoma mansoni infections and with varying degrees of hepatic impairment. In patients with schistosomiasis, praziquantel pharmacokinetics did not differ significantly between those with normal hepatic function and those with mild hepatic impairment (Child-Pugh class A). However, in patients with moderate to severe hepatic impairment (Child-Pugh class B and C), the half-life, Cmax, and AUC of praziquantel increased progressively with the degree of hepatic impairment. In the Child-Pugh class B group, increases in mean half-life, Cmax, and AUC relative to the normal hepatic function group were 1.58-fold, 1.76-fold, and 3.55-fold, respectively. The corresponding increases in the Child-Pugh class C group were 2.82-fold, 4.29-fold, and 15-fold for half-life, Cmax, and AUC.
Renal Impairment
Excretion of praziquantel may be delayed in patients with renal impairment, but accumulation of unchanged drug is not expected.