Albendazole: Broad-Spectrum Anthelmintic for Effective Parasite Eradication
Albendazole
Albendazole is a benzimidazole carbamate anthelmintic agent with broad-spectrum activity against a wide range of intestinal and tissue-dwelling parasitic worms. It exerts its therapeutic effect through selective inhibition of tubulin polymerization, leading to impaired glucose uptake and depletion of energy stores in susceptible helminths. This mechanism results in irreversible damage to the parasite’s cytoskeletal structure and eventual death. Albendazole demonstrates high efficacy against nematodes, cestodes, and trematodes, making it a cornerstone in the management of parasitic infections in both clinical and public health contexts. The medication is particularly valued for its activity against hydatid disease and neurocysticercosis, conditions that require prolonged anthelmintic therapy.
Features
- Active pharmaceutical ingredient: Albendazole
- Chemical name: Methyl 5-(propylthio)-2-benzimidazolecarbamate
- Molecular formula: C₁₂H₁₅N₃O₂S
- Mechanism: Selective inhibition of parasite β-tubulin polymerization
- Bioavailability: Enhanced approximately 5-fold when administered with fatty foods
- Metabolism: Extensive first-pass metabolism to albendazole sulfoxide (active metabolite)
- Protein binding: Approximately 70% for the sulfoxide metabolite
- Elimination half-life: 8-12 hours for sulfoxide metabolite
Benefits
- Provides comprehensive eradication of both adult and larval forms of susceptible parasites
- Demonstrates ovicidal activity against certain helminth species
- Offers superior tissue penetration compared to other benzimidazoles
- Enables single-dose administration for many intestinal nematode infections
- Shows proven efficacy in complex parasitic diseases including hydatid cyst disease
- Contributes to public health initiatives for parasite control in endemic areas
Common use
Albendazole is indicated for the treatment of various parasitic infections including intestinal nematodiasis (ascariasis, trichuriasis, hookworm infections, and enterobiasis), neurocysticercosis caused by Taenia solium larvae, and hydatid disease caused by Echinococcus granulosus. It is also used off-label for other tissue helminth infections including gnathostomiasis, cutaneous larva migrans, and microsporidiosis. In public health programs, albendazole is employed in mass drug administration campaigns for soil-transmitted helminth control in endemic regions. The World Health Organization includes albendazole in its List of Essential Medicines, underscoring its importance in global health.
Dosage and direction
Dosage varies significantly based on the specific parasitic infection being treated. For intestinal nematode infections in adults and children over 2 years: 400 mg as a single dose (repeated after 2-3 weeks for enterobiasis). For neurocysticercosis: 400 mg twice daily with meals for 8-30 days, depending on cyst resolution. For hydatid disease: 400 mg twice daily with meals for 28-day cycles followed by 14-day drug-free intervals, typically for 3 cycles. Pediatric dosing for hydatid disease: 15 mg/kg/day divided into two doses (maximum 800 mg daily). Administration with a fatty meal increases bioavailability approximately 5-fold. Tablets should be swallowed whole with water; crushing or chewing is not recommended.
Precautions
Hepatic function should be monitored before and during treatment, particularly with prolonged therapy. Complete blood counts should be assessed at beginning and every 2 weeks during long-term therapy due to potential bone marrow suppression. Use with caution in patients with pre-existing liver disease or impaired hepatic function. retinal examinations are recommended before and during treatment for neurocysticercosis due to possible retinal damage. Corticosteroid therapy should be initiated before starting albendazole for neurocysticercosis to prevent inflammatory reactions to dying parasites. Pregnancy should be excluded before initiation and effective contraception maintained during and for one month after treatment.
Contraindications
Hypersensitivity to albendazole, other benzimidazoles, or any component of the formulation. Pregnancy (category C) due to potential teratogenic effects demonstrated in animal studies. Breastfeeding is not recommended during therapy. History of bone marrow suppression. Pre-existing uncontrolled hepatic dysfunction. Retinal lesions in patients with neurocysticercosis may represent a relative contraindication requiring careful risk-benefit assessment.
Possible side effect
The most commonly reported adverse effects include abdominal pain, nausea, vomiting, headache, dizziness, and transient elevation of liver enzymes. Less frequent effects include leukopenia, thrombocytopenia, pancytopenia, alopecia (usually reversible), and allergic reactions including rash and pruritus. Rare but serious adverse effects include Stevens-Johnson syndrome, toxic epidermal necrolysis, and agranulocytosis. In neurocysticercosis, intracranial hypertension and meningeal signs may occur due to inflammatory response to dying parasites. Hepatic toxicity ranging from elevated transaminases to acute liver failure has been reported, particularly with prolonged high-dose therapy.
Drug interaction
Albendazole metabolism is primarily mediated by cytochrome P450 1A2, making it susceptible to interactions with inhibitors (cimetidine, fluvoxamine, some fluoroquinolones) and inducers (omeprazole, phenytoin, carbamazepine) of this enzyme. Cimetidine increases albendazole sulfoxide levels approximately 2-fold. Dexamethasone decreases albendazole sulfoxide levels by approximately 50%. Praziquantel increases albendazole sulfoxide concentrations by approximately 50%. Anticonvulsants (phenytoin, carbamazepine, phenobarbital) may decrease albendazole levels. Theophylline clearance may be decreased when co-administered with albendazole.
Missed dose
If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Doubling of doses to make up for a missed dose is not recommended. For single-dose regimens for intestinal parasites, if vomiting occurs within 3 hours of administration, the dose should be repeated. For multi-dose regimens, consistency in timing relative to meals is important to maintain stable drug levels.
Overdose
Symptoms of overdose may include severe nausea, vomiting, abdominal cramping, diarrhea, dizziness, and headache. In massive overdose, hepatic injury, bone marrow suppression, or neurological symptoms may occur. There is no specific antidote for albendazole overdose. Management should include gastric lavage if presentation is early after ingestion, activated charcoal administration, and supportive care with monitoring of hepatic function and complete blood count. Hemodialysis is not likely to be effective due to high protein binding of the active metabolite.
Storage
Store at controlled room temperature (20-25°C or 68-77°F) in a dry place protected from light and moisture. Keep in the original container with the lid tightly closed. Do not store in bathroom cabinets where humidity levels may fluctuate. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging. Properly discard any unused medication according to local regulations for pharmaceutical waste disposal.
Disclaimer
This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions should be made by qualified healthcare professionals based on individual patient circumstances. The prescribing physician should be consulted for specific dosage recommendations and treatment duration. While every effort has been made to ensure accuracy, medical knowledge evolves and the most current prescribing information should always be consulted. Patients should not alter or discontinue medication without medical supervision.
Reviews
Clinical studies demonstrate albendazole’s efficacy with cure rates of 90-100% for ascariasis, 70-90% for hookworm, and 60-90% for trichuriasis. In neurocysticercosis, albendazole shows superior cyst reduction compared to praziquantel with complete resolution in approximately 80% of cases after multiple cycles. For hydatid disease, albendazole achieves cure or significant improvement in 70-80% of patients with uncomplicated cysts. The medication is generally well-tolerated with most adverse effects being mild and transient. Long-term safety data support its use in mass drug administration programs with minimal serious adverse events when used according to guidelines.