POVAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for POVAN (POVAN).
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.
| Metabolism | 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. |
| Excretion | Primarily fecal (90%) as unchanged drug via bile; renal excretion is minimal (<1%) |
| Half-life | Terminal elimination half-life is approximately 16 hours; clinically, this supports single-dose administration with slow elimination |
| Protein binding | Bound to plasma proteins (especially albumin) approximately 75–80% |
| Volume of Distribution | Apparent volume of distribution is 0.5–0.7 L/kg, consistent with moderate tissue distribution |
| Bioavailability | Oral bioavailability is low (<10%) due to poor absorption; acts topically in the GI tract |
| Onset of Action | Oral: onset of action occurs within 2–4 hours; drug acts locally in the GI tract with minimal systemic absorption |
| Duration of Action | Duration is sustained for 7–10 days due to slow GI transit and enterohepatic recycling; single dose eradicates Enterobius vermicularis |
| Molecular Weight | 1151.41 |
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.
| Dosage form | TABLET |
| Renal impairment | No specific guidelines; caution in severe renal impairment (CrCl <30 mL/min) due to limited data. |
| Liver impairment | Contraindicated in acute hepatic disease or significant liver impairment (Child-Pugh class B or C); use not recommended. |
| Pediatric 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. |
| Geriatric use | No specific adjustments; use standard dosing with caution due to potential comorbidities and reduced hepatic function. |
| 1st trimester | Pyrvinium pamoate (Povan) is generally avoided in the first trimester due to lack of safety data; animal studies have shown embryotoxic effects at high doses. |
| 2nd trimester | Limited data; use only if clearly needed and no alternative. No known teratogenicity in humans. |
| 3rd trimester | Use with caution; minimal systemic absorption reduces fetal exposure, but safety not established. |
Clinical note
Comprehensive clinical and safety monograph for POVAN (POVAN).
| Placental transfer | Based on low oral absorption and high molecular weight, placental transfer is expected to be minimal; however, no direct studies confirm this. |
| Breastfeeding | Pyrvinium is poorly absorbed orally, and breast milk levels are likely negligible. However, due to lack of data, caution is advised; consider alternative treatments for enterobiasis in breastfeeding women. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to pyrvinium pamoateIntestinal obstruction
| Precautions | 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. |
| Food/Dietary | No specific food interactions. The drug should be taken with food to reduce gastrointestinal upset. |
| Clinical Pearls | 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. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | 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. |
| Fetal Monitoring | No specific monitoring required. Monitor for gastrointestinal adverse effects. In pregnancy, assess maternal tolerance and confirm need for antiparasitic therapy. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data lacking. |
| Patient Advice | 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. |