Albendazole: Broad-Spectrum Anthelmintic for Effective Parasite Elimination
Albendazole is a benzimidazole carbamate anthelmintic agent with broad-spectrum activity against intestinal and tissue-dwelling nematodes and cestodes. This synthetic compound demonstrates potent vermicidal and ovicidal properties through selective inhibition of parasite-specific β-tubulin polymerization, disrupting microtubule formation and energy metabolism. Its unique pharmacokinetic profile, characterized by poor oral bioavailability that significantly enhances with fatty meals and extensive first-pass metabolism to the active sulfoxide metabolite, makes it a cornerstone in clinical parasitology. Medical professionals worldwide rely on albendazole for its proven efficacy in managing both common helminthic infections and complex parasitic diseases.
Features
- Chemical name: Methyl 5-(propylthio)-2-benzimidazolecarbamate
- Molecular formula: C₁₂H₁₅N₃O₂S
- Molecular weight: 265.33 g/mol
- White to off-white crystalline powder
- Poor aqueous solubility (0.2 mg/mL at 25°C)
- Melting point: 208-210°C
- Available as 200 mg and 400 mg chewable tablets
- Oral suspension formulation available (100 mg/5 mL)
- Lipophilic properties enhancing tissue penetration
- Active against both adult worms and larval stages
Benefits
- Demonstrates high cure rates against numerous nematode and cestode infections
- Provides ovicidal activity, reducing environmental contamination and reinfection risk
- Offers single-dose efficacy for many intestinal helminth infections
- Exhibits excellent tissue penetration for treatment of systemic parasitic diseases
- Shows minimal development of parasite resistance compared to other anthelmintics
- Cost-effective treatment option with favorable safety profile in mass drug administration programs
Common use
Albendazole is indicated for the treatment of various parasitic infections including soil-transmitted helminthiases (ascariasis, trichuriasis, hookworm infections), enterobiasis, strongyloidiasis, and giardiasis. It serves as the drug of choice for neurocysticercosis caused by Taenia solium larvae and hydatid disease caused by Echinococcus granulosus. The World Health Organization includes albendazole in its Model List of Essential Medicines for its critical role in preventive chemotherapy programs targeting neglected tropical diseases. Off-label uses include treatment of cutaneous larva migrans, microsporidiosis in immunocompromised patients, and as part of combination therapy for certain filarial infections.
Dosage and direction
Dosage varies significantly based on the specific parasitic infection, patient weight, and clinical context. For intestinal helminth infections in adults and children over 2 years: 400 mg single dose (repeated after 2-3 weeks for enterobiasis). For neurocysticercosis: 15 mg/kg/day in two divided doses (maximum 800 mg/day) with meals for 8-30 days. For hydatid disease: 15 mg/kg/day in two divided doses (maximum 800 mg/day) with meals for 28-day cycles followed by 14-day drug-free intervals.
Administration with a fatty meal increases bioavailability by up to fivefold. Tablets should be chewed or crushed and swallowed with water. For patients unable to swallow tablets, the oral suspension should be shaken well before administration. Duration of treatment ranges from single-dose therapy to multiple cycles spanning several months depending on infection type and severity.
Precautions
Hepatic function should be monitored before and during treatment, with transaminase levels checked every 2 weeks during prolonged therapy. Complete blood counts should be performed regularly due to potential bone marrow suppression. Use with caution in patients with pre-existing liver disease or biliary obstruction. Corticosteroid therapy should be initiated concurrently for neurocysticercosis to prevent inflammatory reactions to dying parasites. Effective contraception must be maintained during and for one month after treatment due to teratogenic risks. Breastfeeding should be discontinued during therapy.
Contraindications
Absolute contraindications include known hypersensitivity to albendazole, other benzimidazoles, or any component of the formulation. Pregnancy constitutes an absolute contraindication due to demonstrated embryotoxicity and teratogenicity in animal studies. Not recommended for children under 1 year due to limited safety data. Avoid use in patients with retinal lesions from ocular cysticercosis due to risk of irreversible damage from inflammatory reactions.
Possible side effect
The most common adverse reactions include transient abdominal pain, nausea, vomiting, and headache occurring in approximately 6% of patients. Elevated liver enzymes (2-4% of patients) and reversible alopecia (1-2%) may occur with prolonged therapy. Rare but serious effects include leukopenia (0.6%), thrombocytopenia (0.3%), and pancytopenia (0.1%). Neurological side effects including dizziness, meningeal signs, and increased intracranial pressure may occur during treatment of neurocysticercosis. Hypersensitivity reactions including rash, pruritus, and urticaria occur in less than 1% of patients.
Drug interaction
Cimetidine, dexamethasone, and praziquantel increase plasma levels of albendazole sulfoxide metabolite. Carbamazepine, phenytoin, and rifampin decrease plasma levels through induction of cytochrome P450 enzymes. May potentiate effects of other myelosuppressive drugs. Concurrent use with metronidazole may increase risk of Stevens-Johnson syndrome. Antacids and proton pump inhibitors may reduce absorption of albendazole.
Missed dose
If a dose is missed, it should be taken as soon as remembered unless it is nearly 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 missed doses is not recommended. For single-dose regimens used in intestinal helminth infections, the missed dose should be taken immediately when remembered.
Overdose
Symptoms of overdose may include severe nausea, vomiting, abdominal pain, dizziness, and headache. Massive overdose may lead to liver injury, bone marrow suppression, or neurological toxicity. There is no specific antidote. Gastric lavage may be considered if performed soon after ingestion. Supportive care including monitoring of hematological and hepatic parameters is essential. Hemodialysis is not effective due to high protein binding of the active metabolite.
Storage
Store at controlled room temperature (15-30°C) in original container. Protect from light and moisture. Keep tablets in tightly closed containers. Oral suspension should be stored upright and used within the period specified after opening. Keep out of reach of children and pets. Do not use beyond the expiration date printed on packaging.
Disclaimer
This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions must be made by qualified healthcare professionals based on individual patient circumstances. Always follow local prescribing guidelines and regulatory approvals. The prescriber should be familiar with complete prescribing information including boxed warnings regarding teratogenicity.
Reviews
Clinical studies demonstrate cure rates of 72-98% for ascariasis, 65-90% for hookworm infections, and 28-70% for trichuriasis depending on intensity of infection. In neurocysticercosis, albendazole shows 60-85% reduction in number of viable cysts and 70-90% resolution of seizures with appropriate therapy. For hydatid disease, studies indicate 30-50% cure rate and 30-40% improvement rate with medical therapy alone. Systematic reviews confirm albendazole’s superiority over mebendazole for soil-transmitted helminths and equivalent efficacy to praziquantel for some cestode infections with better tolerability profile.