Anthelmintic (praziquinoline) Pregnancy: Published studies have not identified an association between praziquantel use in pregnancy and major birth defects, miscarriage, or adverse maternal/fetal outcomes (US label).

Praziquantel

Brand names: Cysticide

Praziquantel is an anthelmintic used to treat infections caused by schistosomes (schistosomiasis) and other trematodes and cestodes, including many tapeworm (cestode) infections.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Schistosomiasis: 20 mg/kg bodyweight three times a day, each dose separated by 4 to 6 hours, for 1 day only

Route: Oral

Frequency: 3 times daily (doses 4-6 hours apart), for 1 day

Max: Highest recommended human daily dose 75 mg/kg/day

Clonorchiasis and opisthorchiasis: 25 mg/kg three times a day separated by 4-6 hours for 1 day only. Take tablets with water during meals; do not chew or hold in the mouth (bitter taste may cause gagging/vomiting). 600 mg scored tablets split into four 150 mg segments to adjust to bodyweight. Elderly: substantially renally excreted, greater risk of toxicity with decreased renal function. Paediatric (1-17 yrs): dosing established, similar adverse reactions to adults; for patients under 6 years tablets may be crushed/disintegrated and mixed with semi-solid food or liquid (use within 1 hour); safety under 1 year not established. Verify paediatric dosing against a children's formulary.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Known hypersensitivity to praziquantel or any excipient
Ocular cysticercosis (parasite destruction within the eye may cause irreversible lesions)
Concomitant use of strong CYP3A inducers such as rifampin

Side effects

Malaise, pyrexia
Headache, dizziness
Abdominal discomfort, nausea
Urticaria

Interactions

Strong CYP3A inducers (e.g. rifampin) - contraindicated; reduce praziquantel exposure/efficacy
Moderate CYP3A inducers (e.g. efavirenz) - avoid unless benefit outweighs risk
CYP450 inhibitors (cimetidine, ketoconazole, itraconazole, erythromycin, ritonavir) may increase plasma concentrations
Grapefruit juice increases praziquantel Cmax (~1.6x) and AUC (~1.9x)

Clinical monograph

How it works

It increases parasite cell membrane permeability to calcium, causing sustained muscular contraction, paralysis and tegumental damage that exposes the worm to host immune attack.

Prescribing in practice

It is contraindicated in ocular cysticercosis, and in neurocysticercosis it can provoke harmful inflammatory reactions, so specialist supervision and consideration of corticosteroid cover are required.
Concomitant strong hepatic enzyme inducers can markedly lower praziquantel concentrations and reduce efficacy.
Tablets are best taken with food and swallowed whole to limit the bitter taste that may cause gagging.

Monitoring

Routine laboratory monitoring is not generally required, but neurological status should be observed when treating central nervous system parasitic disease.

Counselling the patient

Take the tablets with food and swallow them whole with water.
Drowsiness or dizziness can occur, so take care with driving until you know how it affects you.
Report severe headache or neurological symptoms if being treated for an infection involving the brain.

Evidence & guidelines

Praziquantel is the WHO-recommended drug of choice for all forms of schistosomiasis.

Reference: UKHSA; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways