2.1 Recommended Dosage

Schistosomiasis The recommended dosage for the treatment of schistosomiasis is 20 mg/kg bodyweight administered orally three times a day separated by 4 to 6 hours, for 1 day only.

2.2 Administration

Take tablets with water during meals. Do not chew or keep the tablets (or parts of tablets) in the mouth; the bitter taste may cause gagging or vomiting. To prevent choking in pediatric patients under 6 years of age, the tablets may be crushed or disintegrated and mixed with semi-solid food or liquid. Use crushed or disintegrated tablets within 1 hour of mixing.

Biltricide 600 mg tablets have three scores which can be split into four segments at the scores. When broken, each of the four segments contains 150 mg of praziquantel so that the dosage can be adjusted to the patient’s bodyweight. Segments are broken off by pressing the score (notch) with thumbnails. If one-quarter of a tablet is required, this is best achieved by breaking the segment from the outer end.

5.1 Clinical Deterioration

The use of Biltricide in patients with schistosomiasis may be associated with clinical deterioration (for example, paradoxical reactions, serum sickness Jarisch-Herxheimer like reactions: sudden inflammatory immune response suspected to be caused by the release of schistosomal antigens). These reactions predominantly occur in patients treated during the acute phase of schistosomiasis. They may lead to potentially life-threatening events, for example, respiratory failure, encephalopathy, papilledema, and/or cerebral vasculitis.

5.2 Central Nervous System (CNS) Effects

Biltricide can exacerbate central nervous system pathology due to schistosomiasis, paragonimiasis, or Taenia solium cysticercosis. As a general rule, consider whether to administer Biltricide to individuals reporting a history of epilepsy and/or other signs of potential central nervous systems involvement such as subcutaneous nodules suggestive of cysticercosis unless the potential benefit justifies the potential risk. Hospitalize the patient for duration of treatment when schistosomiasis or fluke infection is found to be associated with cerebral cysticercosis.

5.3 Potential Lack of Efficacy During the Acute Phase of Schistosomiasis

Data from two observational cohort studies in patients indicate that treatment with Biltricide in the acute phase of infection may not prevent progression from asymptomatic infection to acute schistosomiasis, or from asymptomatic infection/acute schistosomiasis into chronic phase.

5.4 Cardiac Arrhythmias

Bradycardia, ectopic rhythms, ventricular fibrillation, and AV blocks has been observed with Biltricide administration. Monitor patients with cardiac arrhythmias during treatment.

5.5 Hepatic Impairment in Hepatosplenic Schistosomiasis Patients

Reduced hepatic metabolism of praziquantel results in higher and sustained plasma concentrations of unmetabolized praziquantel in patients with liver impairment [see Clinical Pharmacology (12.3)]. Monitor patients for adverse reactions when administering the recommended dose of Biltricide to hepatosplenic schistosomiasis patients with moderate or severe liver impairment (Child-Pugh Class B or C).

5.6 Concomitant Administration with Cytochrome P450 Enzyme Inducers

7.1 CYP 3A Inducers

7.2 CYP450 inhibitors

Concomitant administration of drugs that decrease the activity of drug metabolizing liver enzymes (CYP450 inhibitors), for example, cimetidine, ketoconazole, itraconazole, erythromycin, and ritonavir may increase plasma concentrations of praziquantel. In addition, grapefruit juice was also reported to produce a 1.6-fold increase in the Cmax and a 1.9-fold increase in the AUC of praziquantel. The effect of this exposure increase on the safety of Biltricide has not been systematically evaluated [see Dosage and Administration (2.2)].

Risk Summary

Published studies have not identified an association with Biltricide use during pregnancy and major birth defects, miscarriage or adverse maternal or fetal outcomes (see Data). In animal reproduction studies conducted in pregnant rats and rabbits no adverse developmental outcomes were observed with oral administration of praziquantel during organogenesis at approximately 0.65 times (rats) or 1.3 times (rabbits) the highest recommended human daily dose of 75 mg/kg/day, based on body surface area.

The estimated background risk of major birth defects and miscarriage for the indicated population are unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Data

8.2 Lactation

8.4 Pediatric Use

Safety and dosing recommendations of Biltricide in pediatric patients 1 to 17 years have been established. Safety of Biltricide in pediatric patients younger than 1 year of age has not been established.

Post-marketing experience and published literature indicates that pediatric patients 1 to 17 years of age treated with praziquantel experience similar adverse reactions as adults treated with praziquantel [see Adverse Reactions (6)].

8.5 Geriatric Use

Clinical studies of Biltricide 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 [see Clinical Pharmacology (12.3)].

8.6 Hepatic Impairment

Following oral administration of Biltricide to patients with liver impairment, reduced hepatic metabolism of praziquantel results in higher and sustained plasma concentrations of unmetabolized praziquantel [see Clinical Pharmacology (12.3)]. Monitor patients for adverse reactions when administering the recommended dose of Biltricide to hepatosplenic schistosomiasis patients with moderate or severe liver impairment (Child-Pugh Class B or C).

8.7 Renal Impairment

No dosage adjustment of Biltricide is necessary in patients with renal impairment. Nephrotoxic effects of Biltricide or its metabolites are not known [see Clinical Pharmacology (12.3)].

12.1 Mechanism of Action

Praziquantel is an anthelmintic drug [see Microbiology (12.4)].

12.3 Pharmacokinetics

12.4 Microbiology

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. However, the mechanism of action is unknown.

Praziquantel is active against schistosoma (for example, Schistosoma mekongi, Schistosoma japonicum, Schistosoma mansoni and Schistosoma hematobium), and infections due to the liver flukes, Clonorchis sinensis/Opisthorchis viverrini[see Indications and Usage (1)]. Published in vitro data have shown a potential lack of efficacy of praziquantel against migrating schistosomulae [see Warnings and Precautions (5.3)].

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Mutagenicity studies of praziquantel published in the scientific literature are inconclusive. Long term oral carcinogenicity studies in rats and golden hamsters did not reveal any carcinogenic effect at doses up to 250 mg/kg/day (about half of the human daily dose based on body surface area). Praziquantel had no effect on fertility and general reproductive performance of male and female rats when given at oral doses ranging from 30 to 300 mg/kg body weight (up to 0.65 times the human daily dose based on body surface area).