Albendazole is a benzimidazole carbamate anthelmintic agent with broad-spectrum activity against intestinal and tissue-dwelling nematodes and cestodes. This synthetic compound demonstrates 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 plasma, bile, hepatic cysts, and cerebrospinal fluid. The medication represents a cornerstone in clinical parasitology for both individual treatment and mass drug administration programs due to its favorable efficacy-to-safety profile and well-characterized pharmacokinetics.

Features

• Molecular formula: C₁₂H₁₅N₃O₂S
• Chemical name: Methyl 5-(propylthio)-2-benzimidazolecarbamate
• White to off-white crystalline powder
• Poor aqueous solubility (0.2 mg/mL at 25°C)
• Administered orally as tablets or suspension
• Requires fatty meal for optimal absorption (approximately 5-fold increase in bioavailability)
• Plasma half-life: 8-12 hours (active metabolite)
• Protein binding: approximately 70%
• Extensive hepatic metabolism via cytochrome P450 system
• Excretion primarily in bile (with enterohepatic recycling) and urine

Benefits

• Demonstrates high cure rates against numerous nematode and cestode infections
• Provides ovicidal activity, reducing environmental contamination and transmission risk
• Achieves therapeutic concentrations in difficult-to-treat locations including cysts, eyes, and CNS
• Enables single-dose administration for many intestinal helminthiases
• Offers cost-effective treatment suitable for resource-limited settings
• Shows activity against both larval and adult parasite forms

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. Off-label uses include treatment of cutaneous larva migrans, microsporidiosis in immunocompromised patients, and as part of combination therapy for gnathostomiasis. The World Health Organization includes albendazole in its Model List of Essential Medicines and recommends it for preventive chemotherapy in endemic areas for soil-transmitted helminthiases.

Dosage and direction

Dosage must be individualized based on infection type, patient weight, and hepatic function. 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 separated by 14-day drug-free intervals. For intestinal helminths: single 400 mg dose for adults and children over 2 years (200 mg for children 1-2 years). Administration with a fatty meal increases bioavailability approximately 5-fold. Tablets should be swallowed whole with water; the suspension should be shaken well before use. Patients should be advised to complete the full course of treatment even if symptoms improve earlier.

Precautions

Monitor complete blood count before treatment and every 2 weeks during prolonged therapy due to risk of bone marrow suppression. Hepatic enzymes should be monitored before and during treatment, particularly with pre-existing liver dysfunction. Use with caution in patients with retinal lesions or history of photosensitivity reactions. Corticosteroid therapy should be co-administered for neurocysticercosis to prevent cerebral hypertension and 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

Hypersensitivity to albendazole, other benzimidazoles, or any component of the formulation. Pregnancy (category C) due to demonstrated teratogenicity and embryotoxicity in animal studies. Patients with known cirrhosis or significant hepatic impairment. History of bone marrow suppression or pre-existing hematological disorders. Concurrent use with ritonavir due to significant interaction potential. Children under 1 year of age due to limited safety data.

Possible side effect

Common adverse reactions (>1%) include headache, dizziness, nausea, vomiting, abdominal pain, diarrhea, and transient elevation of liver enzymes. Less frequent effects (<1%) include leukopenia, thrombocytopenia, pancytopenia, alopecia, fever, skin rash, and pruritus. Rare but serious reactions include Stevens-Johnson syndrome, toxic epidermal necrolysis, acute liver failure, and agranulocytosis. Ocular side effects may include retinal changes and visual impairment. Neurological effects can include meningeal signs, increased intracranial pressure, and vertigo.

Drug interaction

Cimetidine, dexamethasone, and praziquantel increase plasma levels of albendazole sulfoxide. Carbamazepine, phenytoin, and phenobarbital may decrease albendazole concentrations. Ritonavir significantly reduces albendazole sulfoxide levels and is contraindicated. Theophylline metabolism may be inhibited, requiring monitoring. Warfarin efficacy may be reduced due to induction of metabolism. Albendazole may decrease the efficacy of oral contraceptives, requiring additional contraceptive methods.

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 administration. For single-dose regimens for intestinal helminths, the dose may be taken when remembered without regard to meals, though a fatty meal is still recommended.

Overdose

Symptoms of overdose may include severe nausea, vomiting, dizziness, headache, and drowsiness. In massive overdose, bone marrow suppression, hepatitis, or renal impairment may occur. There is no specific antidote. Gastric lavage may be considered if performed soon after ingestion. Activated charcoal may be administered. Supportive care should include monitoring of hematological parameters and hepatic function. Hemodialysis is not effective due to high protein binding.

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 suspension. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Discard any unused suspension after the prescribed treatment course.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Treatment decisions must be made by qualified healthcare professionals based on individual patient circumstances. The prescribing physician should be consulted for specific dosing recommendations and management of adverse effects. Patients should not self-medicate with albendazole without proper diagnosis and medical supervision.

Reviews

Clinical studies demonstrate albendazole efficacy rates of 72-98% for ascariasis, 65-92% for hookworm, and 28-70% for trichuriasis. In neurocysticercosis, albendazole shows 67-85% cyst resolution rates with concomitant steroid therapy. For hydatid disease, studies report cure rates of 30-50% and improvement in 30-50% of patients with multiple cycles. Systematic reviews confirm albendazole’s superiority over mebendazole for soil-transmitted helminths, particularly against hookworm infections. The medication is generally well-tolerated, with most adverse effects being mild and transient.