Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
POVAN vs ERGAMISOL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Pyrvinium pamoate inhibits oxidative metabolism and glucose uptake in susceptible helminths, leading to energy depletion and paralysis of the worm. It also binds to DNA and inhibits RNA synthesis in the parasite.
Levamisole is an anthelmintic and immunomodulator. It acts as a nicotinic acetylcholine receptor agonist at the neuromuscular junction in nematodes, causing spastic paralysis. Its immunomodulatory effects are thought to involve stimulation of T-cell activation and phagocytosis.
Treatment of enterobiasis (pinworm infection) caused by Enterobius vermicularis
Adjuvant therapy in combination with fluorouracil for the treatment of Dukes' C colon cancer (FDA-approved, now discontinued),Off-label: treatment of steroid-resistant nephrotic syndrome in children, and as an adjuvant in melanoma and other cancers
Pyrantel pamoate: 11 mg/kg (maximum 1 g) orally once; repeat in 2 weeks for pinworm. For ascariasis, hookworm, trichostrongyliasis: 11 mg/kg (max 1 g) once daily for 3 days.
150 mg orally once daily
Terminal elimination half-life is approximately 16 hours; clinically, this supports single-dose administration with slow elimination
2-4 hours (terminal); prolonged in hepatic impairment (up to 8-12 hours) and renal impairment (increase by 1.5- to 2-fold).
Pyrvinium pamoate is minimally absorbed from the gastrointestinal tract; systemic metabolism is negligible. The small absorbed fraction is metabolized in the liver, but specific enzymes are not well defined.
Hepatic metabolism primarily via CYP450 enzymes (CYP2B6 and CYP3A4) to active metabolites. Levamisole undergoes extensive biotransformation to its major metabolites, p-hydroxy-levamisole and levamisole sulfoxide.
Primarily fecal (90%) as unchanged drug via bile; renal excretion is minimal (<1%)
Renal (parent drug and metabolites): ~70% in urine; Fecal: ~25% primarily as metabolites; <5% unchanged in urine.
Bound to plasma proteins (especially albumin) approximately 75–80%
20-30%, primarily to albumin.
Apparent volume of distribution is 0.5–0.7 L/kg, consistent with moderate tissue distribution
1.0-1.5 L/kg; indicates extensive tissue distribution, including penetration into liver and kidneys.
Oral bioavailability is low (<10%) due to poor absorption; acts topically in the GI tract
Oral: 40-60% (extensive first-pass metabolism).
No specific guidelines; caution in severe renal impairment (Cr Cl <30 m L/min) due to limited data.
GFR 30-60 m L/min: no adjustment; GFR <30 m L/min: not recommended
Contraindicated in acute hepatic disease or significant liver impairment (Child-Pugh class B or C); use not recommended.
Child-Pugh A: no adjustment; Child-Pugh B or C: avoid use
Weight-based: 11 mg/kg (maximum 1 g) orally once for pinworm; repeat in 2 weeks. For other infections: 11 mg/kg once daily for 3 days.
2.5 mg/kg orally once daily; maximum 150 mg daily
No specific adjustments; use standard dosing with caution due to potential comorbidities and reduced hepatic function.
No specific adjustment; monitor for renal function and potential QT prolongation
None
None specifically required for ergamisol (levamisole). However, use of levamisole as an immunomodulator has been associated with agranulocytosis and other severe hematologic reactions.
Gastrointestinal disturbances may occur; caution in patients with inflammatory bowel disease or severe hepatic impairment. May cause staining of stools and emesis. Avoid in pregnancy unless clearly needed.
Agranulocytosis (may occur weeks after initiation and is reversible upon discontinuation), hemolytic anemia (especially in patients with G6PD deficiency), neurologic effects (seizures, dizziness, headache), hepatotoxicity, and hypersensitivity reactions.
Hypersensitivity to pyrvinium or any component of the formulation,Intestinal obstruction or acute abdominal conditions
Known hypersensitivity to levamisole; patients with a history of agranulocytosis induced by levamisole; concomitant use with alcohol (disulfiram-like reaction); caution in patients with hepatic or renal impairment.
No specific food interactions. The drug should be taken with food to reduce gastrointestinal upset.
Avoid alcohol during therapy due to potential disulfiram-like reaction (nausea, vomiting, flushing). No specific food restrictions; maintain adequate hydration. Grapefruit juice may inhibit CYP2C19 metabolism, potentially increasing levamisole levels; consider avoidance.
Pyrvinium pamoate (Povan) is not recommended during pregnancy due to insufficient human data. Animal studies have not shown teratogenicity, but risk cannot be excluded. In first trimester, avoid use unless clearly needed. Second and third trimester: consider risk-benefit; no known fetal harm from limited reports.
Ergamisole (levamisole) is classified as FDA Pregnancy Category C. Animal studies have shown embryotoxicity and teratogenicity at doses comparable to human doses. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to fetus. In first trimester, avoid use; second and third trimester, use with caution if indicated.
Unknown if pyrvinium pamoate is excreted in human milk. M/P ratio not available. Caution advised, consider alternative treatment during breastfeeding.
Levamisole is excreted in human milk in low amounts; M/P ratio is not established. Because of potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
No dose adjustment studied in pregnancy. Standard adult dose: 5 mg/kg base (max 350 mg) single dose. Use only if potential benefit justifies risk.
Pharmacokinetics in pregnancy are not well characterized. No specific dose adjustments are recommended; however, due to potential for altered metabolism, use lowest effective dose and monitor maternal toxicity closely.
POVAN (pyrvinium pamoate) is primarily used for enterobiasis (pinworm infection). Administer as a single oral dose; repeat after 2 weeks to prevent reinfection. Tablets should be swallowed whole to avoid staining teeth. Drug may turn stools red. Avoid in patients with gastrointestinal disorders or inflammatory bowel disease. Monitor for nausea, vomiting, and cramping.
Levamisole (ERGAMISOL) is primarily used as an immunomodulator in adjuvant therapy for stage III colon cancer after surgical resection. It is often combined with fluorouracil. Monitor for agranulocytosis, especially in patients with poor metabolizer status of CYP2D6. Agranulocytosis can occur weeks to months after initiation; obtain baseline CBC and repeat periodically. Levamisole can cause a metallic taste and reversible ANCA-positive vasculitis. Avoid in patients with known hypersensitivity or bone marrow depression.
Take the medication exactly as a single dose, and repeat after 2 weeks.,Swallow tablets whole; do not crush or chew to prevent mouth staining.,Stools may appear bright red; this is harmless.,Wash hands thoroughly after using the toilet and before eating to prevent reinfection.,Wash bedding and underwear in hot water; vacuum floors to remove eggs.,Treat all household members simultaneously to avoid spread.,Report persistent abdominal pain or diarrhea to your doctor.
Take levamisole exactly as prescribed, usually for 3 days every 2 weeks for 1 year. Do not miss doses.,Report any signs of infection (fever, sore throat, mouth sores) immediately as it can lower white blood cell count.,You may experience a metallic taste; this is harmless and may resolve with time.,Avoid alcohol consumption as it may increase risk of adverse effects.,Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding.,Do not take any other medications or supplements without consulting your doctor.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about POVAN vs ERGAMISOL, answered by our medical review team.
POVAN is a Anthelmintic that works by Pyrvinium pamoate inhibits oxidative metabolism and glucose uptake in susceptible helminths, leading to energy depletion and paralysis of the worm. It also binds to DNA and inhibits RNA synthesis in the parasite.. ERGAMISOL is a Anthelmintic Immunomodulator that works by Levamisole is an anthelmintic and immunomodulator. It acts as a nicotinic acetylcholine receptor agonist at the neuromuscular junction in nematodes, causing spastic paralysis. Its immunomodulatory effects are thought to involve stimulation of T-cell activation and phagocytosis.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between POVAN and ERGAMISOL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of POVAN is: Pyrantel pamoate: 11 mg/kg (maximum 1 g) orally once; repeat in 2 weeks for pinworm. For ascariasis, hookworm, trichostrongyliasis: 11 mg/kg (max 1 g) once daily for 3 days.. The standard adult dose of ERGAMISOL is: 150 mg orally once daily. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between POVAN and ERGAMISOL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. POVAN is classified as Category C. Pyrvinium pamoate (Povan) is not recommended during pregnancy due to insufficient human data. Animal studies have not shown teratogenicity, but risk cannot be excluded. In first tr. ERGAMISOL is classified as Category C. Ergamisole (levamisole) is classified as FDA Pregnancy Category C. Animal studies have shown embryotoxicity and teratogenicity at doses comparable to human doses. There are no adeq. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.