Pharmacology of Albendazole

Introduction

Albendazole, a benzimidazole anthelmintic, is an FDA-approved medication employed to manage various parasitic worm infections, demonstrating a broad-spectrum efficacy against numerous helminth diseases​^1,​​ ²​.

Mechanism of Action:

The primary mechanism of action revolves around the inhibition of microtubule polymerization. Specifically, the active metabolite of Albendazole, albendazole sulfoxide, induces selective degeneration of cytoplasmic microtubules in the intestinal and tegmental cells of intestinal helminths and larvae. This action leads to glycogen depletion, impaired glucose uptake, and cholinesterase secretion, culminating in the accumulation of desecratory substances intracellularly, which ultimately disrupts the metabolic processes of parasites​³​.

Pharmacokinetics:

• Absorption: Albendazole’s bioavailability is limited due to its poor absorption from the gastrointestinal tract, although this can be enhanced when ingested with a fatty meal.
• Distribution: Post absorption, it’s rapidly metabolized in the liver to its primary active metabolite, albendazole sulfoxide, which is then disseminated throughout the body including in the cerebrospinal fluid and across the placenta.
• Metabolism: The liver extensively metabolizes Albendazole, predominantly to albendazole sulfoxide, via cytochrome P450 enzymes.
• Excretion: The biliary system primarily excretes the metabolites of Albendazole, with a lesser extent of excretion occurring through the urine.

Therapeutic Uses:

The broad therapeutic applications of Albendazole encompass the treatment of gastrointestinal helminthiasis, echinococcosis, neurocysticercosis, ascariasis, trichuriasis, hookworm infection, strongyloidiasis, and other systemic helminth infections.

Adverse Effects:

Common adverse effects are usually mild and transient, encompassing gastrointestinal symptoms such as abdominal pain, nausea, and vomiting. Other side effects may include headache, dizziness, and reversible alopecia. Although rare, hepatic toxicity and bone marrow suppression are serious adverse effects that could occur.

Drug Interactions:

Drug interactions may arise, especially with medications that undergo hepatic metabolism. The concurrent administration of Albendazole with certain medications like anticonvulsants or antiretroviral agents could alter its efficacy and toxicity.

Clinical Efficacy:

The anthelmintic efficacy of Albendazole has been substantiated through numerous studies, with certain studies showcasing cure rates and 0% egg reduction rates​⁴​.

Conclusion:

Albendazole remains a pivotal antihelminthic agent with a well-tolerated profile, making it a vital drug in the management of parasitic infections. Understanding its pharmacology is crucial for healthcare practitioners to ensure its safe and effective utilization in clinical settings.

This chapter is informed by recent updates as of 2023, as referenced from reputable sources including the NCBI, DrugBank, and PubMed among others​^{1, 2,}​​ ^5,​​ ³​​, ⁴​.