Praziquantel

Pronunciation: PRAZ-i-KWON-tel
Class: Antihelmintic

Trade Names

Biltricide
- Tablets 600 mg

Pharmacology

Increases cell membrane permeability in susceptible worms, resulting in loss of intracellular calcium, massive contractions, and paralysis of their musculature. Phagocytes are thus able to attach to worms, causing their death.

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Pharmacokinetics

Absorption

Rapidly absorbed (80%). T _max is 1 to 3 h.

Distribution

Appears in breast milk.

Metabolism

Extensive first-pass metabolism.

Elimination

80% of a dose is excreted in the urine (more than 99% as metabolites). Serum half—life is 0.8 to 1.5 h.

Special Populations

Excretion may be delayed in patients with renal impairment, but accumulation of unchanged drug would not be expected.

C _max , AUC, and half-life were significantly elevated in patients with moderate to severe liver impairment.

Indications and Usage

Infections caused by all species of schistosoma (eg, Schistosoma mekongi , Schistosoma japonicum , Schistosoma mansoni , Schistosoma hematobium ), liver flukes, Clonorchis sinensis , and Opisthorchis viverrini .

Unlabeled Uses

Treatment of neurocysticercosis, tissue flukes ( Nanophyetus salmincola , Opisthorchis felineus , Paragonimus westermani , Fasciola hepatica ), intestinal flukes ( Heterophyes heterophyes , Fascilopsis buski , Metagonimus yokogawai , P. westermani ), intestinal cestodes ( Diphyllobothrium latum , Taenia saginata , Taenia solium , Dipylidium caninum , Hymenolepsis nana , Hymenolepsis diminuta ), schistosomiasis (in concurrent use with oxamniquine), and liver flukes ( Metrochis conjunctus ).

Contraindications

Coadministration with strong CYP–450 inducers (eg, rifampin); hypersensitivity to the drug or any of the excipients; ocular cysticercosis.

Dosage and Administration

PO 75 mg/kg in 3 equally divided doses every 4 to 6 h for 1 day.

PO 60 mg/kg in 3 equally divided doses every 4 to 6 h for 1 day.

General Advice

• The tablets should be taken during meals with water.
• Instruct patient not to chew tablets.

Storage/Stability

Store below 86°F.

Drug Interactions

Praziquantel blood concentrations may be reduced, decreasing the antiparasitic effect. Monitor praziquantel concentrations and adjust the dose as needed. Coadministration of rifampin and praziquantel is contraindicated.

Plasma levels of praziquantel may be elevated, increasing the pharmacologic effect and risk of adverse reactions. Monitor the patient for an increase in adverse reactions. If an interaction is suspected, it may be necessary to decrease the praziquantel dose.

Grapefruit juice ingestion may increase praziquantel plasma concentrations, increasing the effectiveness and risk of adverse reactions. Advise patients taking praziquantel to avoid grapefruit products and to take praziquantel with a liquid other than grapefruit juice.

Adverse Reactions

Cardiovascular

Arrhythmia (including AV blocks, bradycardia, ectopic rhythms, ventricular fibrillation) (postmarketing).

CNS

Dizziness; headache; malaise; asthenia, convulsion, somnolence, vertigo (postmarketing).

Dermatologic

Urticaria; pruritis (postmarketing).

GI

Abdominal discomfort with or without nausea; abdominal pain, anorexia, bloody diarrhea, vomiting (postmarketing).

Hypersensitivity

Allergic reaction (generalized hypersensitivity), including polyserositis (postmarketing).

Miscellaneous

Increased liver enzymes, rise in temperature; eosinophilia, myalgia (postmarketing).

Precautions

Pregnancy

Category B .

Lactation

Excreted in breast milk. Lactating women should avoid breast-feeding on day of treatment and for subsequent 72 h.

Children

Safety and efficacy not established in children younger than 4 y of age.

Hepatic Function

Use with caution at the usual recommended doses in hepatosplenic schistosomiasis patients with moderate to severe liver impairment.

Special Risk Patients

Do not administer to patients with a history of epilepsy and/or signs of potential CNS involvement, such as subcutaneous nodules suggestive of cysticercosis.

Cerebral cysticercosis

When schistosomiasis or fluke infection is associated with cerebral cysticercosis, hospitalize patient for duration of treatment.

Hepatic effects

Minimal increases in liver enzymes have occurred in some patients.

Overdosage

Symptoms

No data available.

Patient Information

• Explain that treatment lasts only 1 day for most parasitic infections.
• Instruct patient to take drug with water during meals and not to chew tablets.
• Advise patient to have all family members examined for infestation.
• Instruct patient to report the following symptoms to health care provider: abdominal pain, dizziness, fever, headache, malaise, nausea, or urticaria.
• Advise patient that drug may cause drowsiness and to use caution while driving or performing other tasks requiring mental alertness.

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