EMVERM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EMVERM (EMVERM).
Mebendazole binds to tubulin, inhibiting microtubule polymerization, which disrupts glucose uptake and causes energy depletion leading to parasite death.
| Metabolism | Primarily hepatic; metabolized by microsomal enzymes (CYP450) to major metabolite 2-aminomebendazole, which is less active; also undergoes further metabolism. |
| Excretion | Primarily fecal (approx. 90%) as unchanged drug and metabolites; <10% excreted renally. |
| Half-life | 2-8 hours; clinical context: the short half-life supports once-daily dosing; metabolites may persist longer. |
| Protein binding | ~90-95% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | ~1-2 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: ~22-40% due to first-pass metabolism; improved with food. |
| Onset of Action | Oral: onset of clinical effect (parasite elimination) within 24-48 hours; tablets may produce effect within hours due to local action. |
| Duration of Action | Single dose provides clinical cure in most cases, but a second dose after 2 weeks is often recommended due to possible reinfection; duration of drug action is about 24-48 hours. |
| Molecular Weight | 493.52 Da |
Mebendazole 100 mg orally twice daily for 3 days for adults and children over 2 years.
| Dosage form | TABLET, CHEWABLE |
| Renal impairment | No adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl <30 mL/min); use with caution. |
| Liver impairment | No adjustment for mild (Child-Pugh A) or moderate (Child-Pugh B) impairment. Avoid use in severe hepatic impairment (Child-Pugh C) due to increased risk of toxicity. |
| Pediatric use | Children ≥2 years: 100 mg orally twice daily for 3 days. Children <2 years: safety not established; use only if potential benefit outweighs risk. |
| Geriatric use | No specific adjustment required; use standard adult dosing. Monitor for adverse effects due to potential age-related renal or hepatic decline. |
| 1st trimester | Avoid; teratogenic effects observed in animal studies. Use only if benefit outweighs risk. |
| 2nd trimester | Use only if clearly needed; limited human data but no increased malformation risk in some studies. |
| 3rd trimester | Use with caution near term; theoretical risk of neurotoxicity or GI effects in neonate. |
Clinical note
Comprehensive clinical and safety monograph for EMVERM (EMVERM).
| Placental transfer | Crosses placenta in animal studies; human data limited but presumed. |
| Breastfeeding | Excreted in human milk in small amounts. Use with caution in nursing mothers; monitor infant for diarrhea or GI upset. |
| Lactation Rating |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to mebendazolePregnancy (first trimester)
| Precautions | Risk of neutropenia and agranulocytosis, especially with high doses or prolonged use, May cause bone marrow suppression; monitor blood counts in prolonged therapy, Hepatotoxicity reported; use caution in hepatic impairment, Seizures have occurred, particularly in patients with history of seizures, Not recommended in pregnancy (pregnancy category C); embryotoxic and teratogenic in animals |
| Food/Dietary | No significant food interactions; absorption is enhanced by fatty foods but not required for efficacy in enterobiasis. Avoid alcohol due to potential hepatotoxicity. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | FDA Pregnancy Category C. Animal studies have shown embryotoxicity and teratogenicity at high doses. Human data are limited; therefore, use during pregnancy only if clearly needed. Risk cannot be ruled out, especially in the first trimester. |
| Fetal Monitoring | No specific maternal or fetal monitoring required; however, assess for hypersensitivity reactions or GI adverse effects. In pregnant women, consider ultrasound if exposure occurs in first trimester. |
| Fertility Effects | Animal studies have reported no adverse effects on fertility at therapeutic doses. Human data are insufficient to determine effects on fertility. |
| Clinical Pearls |
| EMVERM (mebendazole) is poorly absorbed systemically, making it ideal for intraluminal helminth infections. Administer with fatty meal to enhance absorption when systemic effect (e.g., for trichinosis) is desired. Avoid in pregnancy (FDA Category C). Tablets may be chewed, swallowed, or crushed. Monitor for rare agranulocytosis, especially with concurrent metronidazole or high doses. |
| Patient Advice | Take exactly as prescribed; a second course may be needed if reinfection occurs. · Tablets can be chewed, crushed, or swallowed whole with or without food. · Mebendazole works by preventing worms from absorbing sugar, causing their death. · Strict hand hygiene and laundering of bedding/clothing to prevent reinfection. · Treat all household members if pinworm outbreak; withhold treatment in pregnancy unless essential. · Notify provider if fever, sore throat, or unusual bleeding/bruising (agranulocytosis warning). |