Source: Medicines and Medical Devices Safety Authority (NZ) Revision Year: 2017 Publisher: Bayer New Zealand Limited, 3 Argus Place, Hillcrest, North Shore, Auckland 0627, Free phone: 0800 233 988
Known hypersensitivity to praziquantel or any of the excipients.
Ocular cysticercosis – parasite destruction within the eye may cause irreparable damage.
The concomitant administration of strong inducers of Cytochrome P 450 such as rifampicin must be avoided as therapeutically effective plasma levels may not be achieved.
Published in vitro data have shown a potential lack of efficacy of praziquantel against migrating schistosomulae. Data from two observational cohort studies in patients indicate that treatment with praziquantel in the acute phase of infection may not prevent progression into chronic phase.
In addition, the use of praziquantel in patients with schistosomiasis may be associated with clinical deterioration (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 e.g. respiratory failure, encephalopathy, and/or cerebral vasculitis.
Patients suffering from cardiac irregularities should be monitored during treatment.
When schistosomiasis or fluke infection is found in patients living in or coming from areas with endemic human cysticercosis, it is advised to hospitalise the patient for the duration of treatment.
As praziquantel can exacerbate central nervous system pathology due to schistosomiasis, paragonimiasis or Taenia solium cysticercosis, as a general rule this medicine should not be administered to individuals reporting a history of epilepsy and/or other signs of potential central nervous system involvement such as subcutaneous nodules suggestive of cysticercosis.
Neurocysticercosis is not an approved indication due to insufficient data. In animals, venous thrombosis and the development of granulomas at the site of worm attachment has been observed following treatment with praziquantel. Patients treated with praziquantel (for neurocysticercosis) have had a high incidence of severe headache and seizures. Some patients also developed intracranial hypertension. Because of the potential for undiagnosed neurocysticercosis to be present in patients originating from endemic areas, extra care is necessary in managing such patients. If cerebral cysticercosis is present and treatment is still considered essential, the patient should be hospitalized under specialist care.
Since 80% of praziquantel and its metabolites are excreted in the kidneys, excretion might be delayed in patients with impaired renal function. Nephrotoxic effects of praziquantel are not known.
In uncompensated liver insufficiency and in patients with hepatosplenic schistosomiasis caution should be taken, since due to reduced drug metabolisation in the liver, considerably higher and longer lasting concentrations of unmetabolised praziquantel can occur in vascular and/or collateral circulation leading to prolonged plasma half-life. If necessary, the patient may be hospitalised for the duration of the treatment.
Safety in children has not been established.
Praziquantel is believed to be metabolised via the CYP450 enzyme system. Many categories of medicines are known to inhibit or induce CYP450 enzymes causing an increase or decrease in serum concentrations or bioavailability. Care must therefore be exercised when co-administering such medicines.
Concomitant administration of medicines that increase the activity of drug metabolising liver enzymes (CYP450 inducers), e.g. antiepileptic medicines, dexamethasone may reduce plasma levels of praziquantel. Concomitant administration of strong inducers of CYP450 such as rifampicin must be avoided. Chloroquine, when taken simultaneously, can lead to lower concentrations of praziquantel in blood.
Concomitant administration of medicines that decrease the activity of drug metabolising liver enzymes (CYP450 inhibitors) e.g. cimetidine, ketoconazole, itraconazole, erythromycin, may increase plasma levels of praziquantel.
When administered concomitantly with grapefruit juice, an increase in praziquantel exposure of less than twofold was observed in clinical studies.
Reproduction studies performed so far in rats and rabbits have revealed no evidence of impaired fertility or harm to the fetus due to praziquantel. An increase in abortion rate was seen in rats given single doses of 300 mg/kg. There are no adequate and well controlled studies on the use of praziquantel in pregnant women.
Because animal reproduction studies are not always predictive of human response, for safety reasons praziquantel should not be used in pregnancy unless clearly needed.
Praziquantel has been reported to be excreted in the milk of nursing women. Women should not nurse on the day of Biltricide treatment and during the subsequent 72 hours.
Patients should be warned not to drive or operate machinery on the day of treatment (and during the subsequent 24 hours), as their ability to do so may be temporarily impaired by the use of praziquantel.
Adverse Reactions are based on publications and on spontaneous reports sorted by CIOMS III categories of frequency and MedDRA System Organ Classes (in internationally agreed order). Frequencies of Adverse Reactions are mainly based on data from medical literature.
Side effects vary according to dose and duration of praziquantel medication; furthermore they are dependent on the parasite species, extent of parasitisation, duration of infection and localisation of the parasites in the body. Side effects occur earlier and are more frequent and pronounced in patients with severe parasitic infestation. Mild increases in liver enzymes have been reported in some patients.
Table 2. Adverse reactions:
Very Rare: Allergic reaction, Polyserositis, Eosinophilia
Very Common: Headache, Dizziness
Common: Vertigo, Somnolence
Very Rare: Seizures
Very Rare: Unspecified arrhythmias
Very Common: Gastrointestinal and abdominal pains, Nausea, Vomiting
Common: Anorexia, Diarrhoea (very rarely bloody diarrhoea)
Very Common: Urticaria
Common: Rash
Very Rare: Pruritus
Common: Myalgia
Very Common: Fatigue
Common: Feeling unwell (asthenia, malaise), Fever
It is often not clear whether the complaints reported by patients or the undesirable effects reported by the physician are caused by praziquantel itself (I, direct relation), or may be considered to be an endogenous reaction to the death of the parasites produced by praziquantel (II, indirect relation), or are symptomatic observations of the infestation (III, no relation). It may be difficult to differentiate between the possible variations I, II and III.
Reporting suspected adverse reactions after authorisation of the medicine is important. It allows continued monitoring of the benefit/risk balance of the medicine. Healthcare professionals are asked to report any suspected adverse reactions to https://nzphvc.otago.ac.nz/reporting/
Not applicable.
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