PRAZIQUANTEL
Clinical safety rating: safe
Animal studies have demonstrated safety
Praziquantel increases the permeability of schistosome cell membranes to calcium ions, causing severe contraction and paralysis of the worm musculature, leading to dislodgment and death.
| Metabolism | Extensively metabolized in the liver by cytochrome P450 enzymes (CYP3A4) to inactive metabolites; undergoes first-pass metabolism. |
| Excretion | Primarily renal: approximately 80% of metabolites excreted in urine (unchanged drug <0.1%); fecal excretion accounts for about 15%. |
| Half-life | Terminal elimination half-life is 1-1.5 hours for praziquantel; 4-6 hours for its main metabolite (4-hydroxypraziquantel). Half-life prolonged in patients with severe hepatic impairment. |
| Protein binding | Primarily bound to albumin: approximately 80-85% bound. |
| Volume of Distribution | Vd approximately 1-2 L/kg, indicating extensive distribution into tissues. |
| Bioavailability | Oral bioavailability is about 80% (range 60-100%), but can be significantly increased by co-administration with food or grapefruit juice. |
| Onset of Action | Oral: Onset within 1-2 hours post-dose; peak plasma concentration at 1-3 hours. |
| Duration of Action | Duration of clinical effect is 24 hours after a single oral dose, but treatment typically requires one day of multiple doses (e.g., 3 doses in one day) for optimal efficacy. |
20 mg/kg orally three times daily for 1 day for schistosomiasis; 25 mg/kg orally three times daily for 1 day for clonorchiasis and opisthorchiasis; 5-10 mg/kg orally single dose for taeniasis; 15-25 mg/kg orally single dose for hymenolepiasis; 25 mg/kg orally three times daily for 1 day for paragonimiasis, fasciolopsiasis, and heterophyiasis.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment necessary for mild to moderate renal impairment. For severe renal impairment (GFR <30 mL/min), use with caution; consider dose reduction or extended interval due to potential accumulation, although specific guidelines are lacking. Hemodialysis: no supplemental dose needed. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval. Child-Pugh Class C: contraindicated or use with extreme caution; if used, consider further dose reduction and monitor for adverse effects. |
| Pediatric use | Children ≥1 year: same weight-based dosing as adults. For schistosomiasis: 20 mg/kg/dose three times daily for 1 day. For clonorchiasis/opisthorchiasis: 25 mg/kg/dose three times daily for 1 day. For taeniasis: 5-10 mg/kg single dose. For hymenolepiasis: 15-25 mg/kg single dose. For paragonimiasis, fasciolopsiasis, heterophyiasis: 25 mg/kg/dose three times daily for 1 day. Maximum single dose: 2.4 g per day. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
CYP450 inducers like carbamazepine can decrease levels Can cause abdominal discomfort and dizziness.
| Breastfeeding | Praziquantel is excreted into human breast milk; milk-to-plasma ratio is approximately 0.25. Due to potential adverse effects in nursing infants, benefits of therapy should be weighed against risks. Consider withholding breastfeeding for 72 hours after a dose. |
| Teratogenic Risk | Praziquantel is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal harm, but no adequate human studies exist. First trimester exposure: theoretical risk; avoid unless necessary. Second and third trimesters: considered safe when indicated for treatment of parasitic infections outweighing risks. |
■ FDA Black Box Warning
None
| Common Effects | other fluke infections |
| Serious Effects |
Hypersensitivity to praziquantel or any component of the formulation; ocular cysticercosis; concomitant use with strong CYP3A4 inducers (e.g., rifampin) or inhibitors (e.g., ketoconazole) may require dose adjustment.
| Precautions | Use with caution in patients with hepatic impairment; may cause dizziness, drowsiness, and abdominal discomfort; avoid driving or operating machinery until effects are known. For neurocysticercosis, concomitant corticosteroids are recommended to reduce inflammatory response. Not recommended for ocular cysticercosis due to risk of irreversible damage. |
Loading safety data…
| Geriatric use |
| No specific dose adjustment required in elderly patients based on age alone. Use standard adult dosing. Monitor for adverse effects due to potential age-related comorbidities and polypharmacy. Consider renal and hepatic function. |
| Fetal Monitoring | Monitor for maternal adverse effects: dizziness, headache, abdominal pain. No specific fetal monitoring required, but obstetric ultrasound may be considered if exposure occurs during first trimester. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data limited; no significant impact reported. |