Albendazole is a benzimidazole carbamate anthelmintic agent with broad-spectrum activity against intestinal and tissue-dwelling parasitic worms. This synthetic compound demonstrates potent vermicidal and ovicidal properties by selectively inhibiting parasite-specific tubulin polymerization, disrupting microtubule formation, and impairing glucose uptake in susceptible helminths. Its extensive first-pass metabolism produces the active sulfoxide metabolite, which achieves therapeutic concentrations in various tissues, making it particularly effective against systemic parasitic infections. The medication represents a cornerstone in antiparasitic therapy due to its excellent tissue penetration and proven efficacy across multiple nematode and cestode species.

Features

• Chemical name: methyl 5-(propylthio)-2-benzimidazolecarbamate
• Molecular formula: C₁₂H₁₅N₃O₂S
• Mechanism: Selective inhibition of parasite β-tubulin polymerization
• Bioavailability: Approximately 5% (significantly enhanced with fatty meals)
• Protein binding: 70% of the active sulfoxide metabolite
• Half-life: 8-12 hours (active metabolite)
• Metabolism: Extensive first-pass metabolism to albendazole sulfoxide
• Excretion: Primarily biliary; minimal renal excretion

Benefits

• Eradicates multiple parasitic species through vermicidal and ovicidal action
• Achieves therapeutic concentrations in plasma, bile, liver, cyst fluid, and cerebrospinal fluid
• Demonstrates high cure rates against neurocysticercosis and hydatid disease
• Prevents parasite replication by inhibiting microtubule-dependent glucose uptake
• Offers convenient once or twice-daily dosing regimen for improved compliance
• Provides cost-effective treatment for endemic populations in resource-limited settings

Common use

Albendazole is indicated for the treatment of various parasitic infections including neurocysticercosis caused by larval forms of Taenia solium, hydatid disease caused by Echinococcus granulosus, and intestinal infections by Ascaris lumbricoides, hookworm (Ancylostoma duodenale and Necator americanus), Enterobius vermicularis, Trichuris trichiura, and Strongyloides stercoralis. It is also used off-label for cutaneous larva migrans, microsporidiosis, and giardiasis in certain patient populations. The World Health Organization recommends albendazole for mass drug administration programs in endemic areas for soil-transmitted helminthiases.

Dosage and direction

Dosage varies according to the specific parasitic infection being treated. For neurocysticercosis: 400 mg twice daily with meals for 8-30 days. For hydatid disease: 400 mg twice daily with meals for 28-day cycles followed by 14-day drug-free intervals, typically for 3 cycles. For intestinal parasites: single 400 mg dose, repeated after 2-3 weeks if necessary. Pediatric dosing above 2 years: 400 mg single dose or 200 mg twice daily depending on indication. Administration with a fatty meal increases bioavailability approximately 5-fold. Tablets should be swallowed whole with water; crushing or chewing may affect absorption.

Precautions

Hepatic function should be monitored before and during treatment, with transaminase measurements at beginning of each cycle and every 2 weeks during therapy. Complete blood counts should be performed before each treatment cycle and monitored 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 used during and for one month after treatment completion due to teratogenic potential. Retinal examination is recommended in patients receiving high-dose or prolonged therapy.

Contraindications

Absolute contraindications include known hypersensitivity to albendazole, other benzimidazoles, or any component of the formulation. The drug is contraindicated in pregnancy (FDA Pregnancy Category C) due to demonstrated embryotoxicity and teratogenicity in animal studies. Avoid use in patients with significant hepatic impairment where metabolic capacity may be compromised. Not recommended for children under 2 years due to limited safety data. Contraindicated in patients with pre-existing bone marrow suppression or active hematological disorders.

Possible side effect

The most common adverse reactions include elevated liver enzymes (up to 16% of patients), abdominal pain (up to 6%), nausea/vomiting (4%), headache (up to 4%), and dizziness (1-2%). Less frequently reported effects include leukopenia (1%), thrombocytopenia (0.7%), alopecia (0.7%), and fever (0.5%). Rare but serious adverse events include Stevens-Johnson syndrome, toxic epidermal necrolysis, agranulocytosis, pancytopenia, and acute liver failure. In neurocysticercosis, intracranial hypertension may occur due to inflammatory response to dying parasites, requiring appropriate monitoring and management.

Drug interaction

Albendazole sulfoxide concentrations may be increased by cimetidine, dexamethasone, and praziquantel through CYP3A4 inhibition. Anticonvulsants (carbamazepine, phenytoin, phenobarbital) may decrease albendazole sulfoxide levels through CYP3A4 induction. Theophylline levels may be increased when co-administered with albendazole. Concurrent use with other bone marrow suppressants (e.g., zidovudine, ganciclovir) may increase hematological toxicity. Bile acid sequestrants may reduce albendazole absorption and should be administered separately.

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 once-daily dosing regimens, if remembered within 12 hours of the scheduled time, the dose should be taken; if beyond 12 hours, wait until the next scheduled dose. For twice-daily regimens, if remembered within 6 hours, take the dose; if beyond 6 hours, wait until the next scheduled dose.

Overdose

Symptoms of overdose may include severe nausea, vomiting, dizziness, headache, and elevated liver enzymes. In massive overdose, bone marrow suppression, hepatotoxicity, or neurological symptoms may occur. There is no specific antidote for albendazole overdose. Management should include gastric lavage if presentation is within 1-2 hours of ingestion, activated charcoal administration, and supportive care with monitoring of hematological parameters and liver function. Hemodialysis is unlikely to be effective due to high protein binding and extensive tissue distribution.

Storage

Store at controlled room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted between 15°C to 30°C (59°F to 86°F). Protect from light and moisture. Keep in original container with tight closure. Do not store in bathroom or other humid areas. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Properly discard any unused medication after treatment completion.

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 dosing recommendations and monitoring requirements. While every effort has been made to ensure accuracy, medical knowledge evolves and the most current prescribing information should always be consulted.

Reviews

Clinical studies demonstrate albendazole efficacy rates of 72-98% for ascariasis, 92-100% for hookworm infection, and 90-98% for enterobiasis. In neurocysticercosis, complete cyst resolution occurs in approximately 60-85% of patients after one course of therapy, with significant reduction in seizure frequency. For hydatid disease, albendazole shows cure rates of 30-50% and improvement in 40-60% of patients, with many avoiding surgical intervention. Systematic reviews confirm its superiority over mebendazole for soil-transmitted helminths, particularly hookworm infections. The medication is generally well-tolerated with most adverse effects being transient and mild to moderate in severity.