Praziquantel

5 WARNINGS AND PRECAUTIONS Clinical Deterioration : Potentially life threatening clinical deterioration can occur in patients treated during the acute phase of schistosomiasis. ( 5.1 ) Central Nervous System (CNS) Effects : Praziquantel can exacerbate central nervous system pathology due to schistosomiasis. Consider whether to administer to individuals reporting a history of epilepsy and/or other signs of potential central nervous systems involvement such as subcutaneous nodules suggestive of cysticercosis. ( 5.2 ) Potential Lack of Efficacy for Acute Schistosomiasis : This has been reported in observational studies ( 5.3 ). Cardiac Arrhythmias: Bradycardia, ectopic rhythms, ventricular fibrillation, and AV blocks has been observed with praziquantel administration. Monitor patients with cardiac arrhythmias during treatment ( 5.4 ). 5.1 Clinical Deterioration The use of praziquantel 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 Praziquantel can exacerbate central nervous system pathology due to schistosomiasis, paragonimiasis, or Taenia solium cysticercosis. As a general rule, consider whether to administer praziquantel 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 praziquantel 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 praziquantel 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 praziquantel 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 Strong Cytochrome P450 3A Enzyme (CYP 3A) Inducers Concomitant administration of strong CYP 3A inducers, such as rifampin, with praziquantel is contraindicated since therapeutically effective levels of praziquantel are unlikely to be achieved. [see Contraindications (4), Drug Interactions (7.1) and Clinical Pharmacology (12.3) ]. Moderate CYP 3A Inducers Avoid concomitant administration of praziquantel with moderate CYP 3A inducers, such as efavirenz, due to risk of a clinically significant decrease in praziquantel plasma concentrations which may lead to reduced therapeutic effect of praziquantel. [ see Drug Interactions (7.1)] . In patients receiving a clinically significant CYP 3A inducer drug who need immediate treatment for schistosomiasis, alternative agents for schistosomiasis should be considered, where possible. If praziquantel is necessary immediately, increase monitoring for reduced anthelmintic efficacy associated with praziquantel [ see Drug Interactions (7.1)] . In patients receiving a clinically significant CYP 3A inducer drug whose treatment could be delayed, discontinue the CYP 3A inducer drug at least 2 weeks to 4 weeks before administration of praziquantel and, where possible, consider starting alternative medications that are not CYP 3A inducers. The CYP 3A inducer drug can be restarted one day after completion of praziquantel treatment, if needed [see Drug Interactions (7.1) ]