Adult: 100 mg bid for 3 consecutive days or 500 mg as a single dose. A 2nd course of treatment is recommended if the patient is not cured 2-3 weeks after initial treatment. Child: >2 years Same as adult dose.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity. Pregnancy. Concomitant use with metronidazole.
Special Precautions
Patient with Crohn's ileitis or ulcerative colitis. Hepatic impairment. Children. Lactation.
Adverse Reactions
Significant: Reversible liver function disturbances, hepatitis, neutropenia, agranulocytosis. Gastrointestinal disorders: Abdominal pain, diarrhoea, flatulence, nausea, vomiting. Metabolism and nutrition disorders: Anorexia. Nervous system disorders: Dizziness, convulsions. Renal and urinary disorders: Glomerulonephritis. Skin and subcutaneous tissue disorders: Alopecia, angioedema, rash, urticaria. Potentially Fatal: Rarely, toxic epidermal necrolysis, Stevens-Johnson syndrome.
Monitor CBC when used at higher doses and for a prolonged duration. Check for helminth ova in faeces within 3-4 weeks after the initial therapy.
Overdosage
Symptoms: Abdominal cramps, nausea, vomiting and diarrhoea. Rarely, alopecia, reversible liver function disturbances, hepatitis, agranulocytosis, neutropenia, glomerulonephritis (in patients with high doses and prolonged use). Management: Supportive and symptomatic treatment. Activated charcoal may be administered if considered appropriate.
Drug Interactions
Cimetidine may increase the plasma concentration of mebendazole. Potentially Fatal: Concomitant use with metronidazole may lead to Stevens-Johnson syndrome or toxic epidermal necrolysis.
Food Interaction
Increased bioavailability with high-fat meals.
Action
Description: Mebendazole, a benzimidazole carbamate derivative, inhibits cellular tubulin formation in the helminth and causes ultrastructural degenerative changes in its intestine. This results in blockage of glucose uptake and disruption of digestive and reproductive functions leading to immobilisation, inhibition of egg production and death of the helminth. Pharmacokinetics: Absorption: Poorly absorbed from the gastrointestinal tract. Increased bioavailability with high-fat meals. Time to peak plasma concentration: 2-4 hours. Distribution: Crosses the blood-brain barrier and enters breast milk (small amounts). Volume of distribution: 1-2 L/kg. Plasma protein binding: 90-95%. Metabolism: Extensively metabolised in the liver; undergoes enterohepatic recirculation. Excretion: Mainly via faeces (approx 95%, as unchanged drug and metabolites); urine (approx 2-5%, as unchanged drug and metabolites). Elimination half-life: 3-6 hours.
Chemical Structure
Mebendazole Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4030, Mebendazole. https://pubchem.ncbi.nlm.nih.gov/compound/Mebendazole. Accessed Oct. 25, 2022.