Albendazole: Broad-Spectrum Anthelmintic Therapy for Parasitic Infections
Albendazole is a benzimidazole carbamate anthelmintic agent with broad-spectrum activity against intestinal and tissue-dwelling nematodes and cestodes. As a first-line treatment for numerous parasitic infections, it demonstrates potent vermicidal and ovicidal properties through selective inhibition of parasite-specific tubulin polymerization. This comprehensive antiparasitic action makes it an essential therapeutic option in both individual treatment protocols and mass drug administration programs for helminth control. Its unique pharmacokinetic profile, characterized by poor oral bioavailability that significantly enhances with fatty meals, allows for targeted parasiticidal activity while maintaining a generally favorable safety profile when used appropriately.
Features
- Active pharmaceutical ingredient: Albendazole (benzimidazole class)
- Mechanism: Binds to parasite beta-tubulin, inhibiting microtubule assembly
- Formulations: 200 mg and 400 mg chewable tablets; oral suspension (100 mg/5 mL)
- Metabolism: Rapid first-pass metabolism to active sulfoxide metabolite
- Excretion: Primarily biliary; minimal renal excretion
- Pregnancy category: D (contraindicated in pregnancy)
- Regulatory status: WHO Essential Medicine; FDA-approved for specific indications
Benefits
- Provides effective treatment against multiple parasitic organisms with a single agent
- Demonstrates both adulticidal and ovicidal activity, reducing parasite transmission
- Offers convenient once or twice-daily dosing depending on indication
- Shows excellent tissue penetration, including central nervous system penetration for neurocysticercosis
- Cost-effective therapy suitable for mass administration programs in endemic areas
- Well-tolerated profile with most adverse effects being mild and self-limiting
Common use
Albendazole is indicated for the treatment of various parasitic infections including intestinal nematode infections (ascariasis, trichuriasis, hookworm infections, enterobiasis), neurocysticercosis caused by larval forms of Taenia solium, and hydatid disease caused by larval forms of Echinococcus granulosus. It is also used off-label for other tissue nematode infections including cutaneous larva migrans, gnathostomiasis, and loiasis. In public health contexts, it serves as a cornerstone for preventive chemotherapy programs targeting soil-transmitted helminthiases in endemic regions, often administered through school-based deworming programs. The World Health Organization recommends periodic administration in high-prevalence areas to reduce parasite burden and associated morbidity.
Dosage and direction
Dosing varies significantly based on the specific parasitic infection being treated. For intestinal nematodes: 400 mg orally as a single dose for adults and children over 2 years (200 mg for children 1-2 years). 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 requiring 3+ cycles. Administration with a fatty meal increases bioavailability by up to fivefold. Tablets may be crushed and mixed with food for children or those with swallowing difficulties. Hepatic impairment requires dosage adjustment and close monitoring.
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. Patients with neurocysticercosis may experience neurological symptoms due to inflammatory response to dying parasites and may require corticosteroid coverage. Women of childbearing potential should use effective contraception during and for one month after treatment. Retinal examination is recommended before treatment for patients with suspected retinal involvement. Patients should be advised that albendazole may cause dizziness and should avoid driving or operating machinery if affected.
Contraindications
Absolute contraindications include known hypersensitivity to albendazole, other benzimidazoles, or any component of the formulation. The drug is contraindicated in pregnancy due to potential teratogenic effects demonstrated in animal studies. It should not be used in patients with known cirrhosis or significant hepatic impairment. The tablet formulation is contraindicated in children under 1 year of age, though the suspension may be considered in exceptional circumstances under specialist supervision. Avoid use in patients with bone marrow suppression or active hematological disorders.
Possible side effect
The most commonly reported adverse effects include abdominal pain (6%), nausea (4%), vomiting (4%), headache (3%), and dizziness (2%). Elevated liver enzymes occur in approximately 16% of patients receiving prolonged therapy. Less common effects include reversible alopecia (2%), leukopenia (1%), and thrombocytopenia (0.7%). Rare but serious adverse effects include Stevens-Johnson syndrome, toxic epidermal necrolysis, agranulocytosis, pancytopenia, and hepatitis. In neurocysticercosis, intracranial hypertension, meningeal signs, seizures, and focal neurological deficits may occur due to inflammatory responses.
Drug interaction
Albendazole metabolism is primarily mediated by cytochrome P450 1A2, making it susceptible to interactions with inhibitors (cimetidine, fluvoxamine, certain fluoroquinolones) and inducers (carbamazepine, phenytoin, rifampin) of this enzyme. Cimetidine increases albendazole sulfoxide levels by approximately 50%. Dexamethasone increases albendazole sulfoxide levels by approximately 50%. Praziquantel increases plasma levels of albendazole sulfoxide by approximately 50%. Theophylline clearance may be decreased when co-administered with albendazole. Anticonvulsants (carbamazepine, phenytoin, phenobarbital) may decrease albendazole levels.
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. Patients should not double the dose to make up for a missed dose. For once-daily dosing regimens, if remembered within 12 hours of the scheduled time, the dose should be taken; if more than 12 hours have passed, wait until the next scheduled dose. For twice-daily regimens, if remembered within 6 hours, take the dose; if more than 6 hours have passed, wait until the next scheduled dose.
Overdose
Cases of accidental overdose have been reported with doses up to 16 grams. Symptoms may include nausea, vomiting, dizziness, headache, and abdominal pain. In severe cases, hepatic impairment, bone marrow suppression, or neurological symptoms may occur. There is no specific antidote for albendazole overdose. Management should include gastric lavage if presented within 1 hour of ingestion and supportive care. Activated charcoal may be administered. Liver function tests and complete blood counts should be monitored for several weeks following overdose. Hemodialysis is not effective due to high protein binding of the active metabolite.
Storage
Store at controlled room temperature (20-25°C or 68-77°F) in the original container. Protect from light and moisture. Keep the container tightly closed. Do not freeze the oral suspension. Tablets should be protected from excessive heat and humidity. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging. Discard any unused suspension after the recommended period (typically 3 months after opening). Do not transfer tablets or suspension to other containers unless specifically instructed.
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 be consulted. Patients should not initiate or discontinue therapy without professional medical supervision.
Reviews
Clinical studies demonstrate albendazole’s efficacy across multiple parasitic infections. A meta-analysis of 29 randomized controlled trials showed cure rates of 88% for ascariasis, 78% for hookworm, and 42% for trichuriasis. In neurocysticercosis, complete cyst resolution occurs in approximately 60-85% of patients after one cycle of therapy. For hydatid disease, studies show 30-50% cure rates with 30-40% showing significant improvement. The drug is generally well-tolerated, with most adverse effects being mild and transient. Long-term safety data from mass drug administration programs support its favorable benefit-risk profile when used according to guidelines.