Albendazole – A Broad-Spectrum Anthelmintic for Parasitic Infections

 

Introduction:

*Albendazole* is a *broad-spectrum anthelmintic (anti-worm)* medication used to treat a wide range of *intestinal and tissue parasitic infections* caused by *nematodes, cestodes*, and some protozoa. It is on the *WHO’s List of Essential Medicines* and is widely used for *deworming* in both adults and children.

Mechanism of Action:

Albendazole binds to *β-tubulin of parasites*, inhibiting microtubule polymerization. This:

- Disrupts *glucose uptake*

- Depletes *glycogen stores*

- Leads to *paralysis and death* of the parasite

It has *selective toxicity*, meaning it targets parasites with minimal effects on human cells.

Pharmacokinetics:

- *Absorption*: Poor orally (enhanced with fatty meals)

- *Bioavailability*: 5% (increases with food)

- *Metabolism*: Hepatic, rapidly converted to active metabolite *albendazole sulfoxide*

- *Half-life*: ~8.5 hours (active metabolite)

- *Excretion*: Mainly urine (as metabolites)

Pharmacodynamics:

- Effective against:

  - *Nematodes*: Ascaris, Hookworm, Pinworm

  - *Cestodes*: Taenia, Echinococcus

  - *Tissue parasites*: Neurocysticercosis, Hydatid disease

- Causes death of worms over days to weeks, depending on species

Indications:

- *Intestinal helminth infections*:

  - Ascariasis

  - Enterobiasis (pinworm)

  - Hookworm

  - Trichuriasis

- *Tissue infections*:

  - Neurocysticercosis (brain tapeworm)

  - Hydatid disease (Echinococcosis)

- *Other uses*:

  - Strongyloidiasis

  - Giardiasis (off-label)

  - Mass deworming programs in endemic regions

Contraindications:

- Hypersensitivity to albendazole or benzimidazoles  

- *Pregnancy (especially first trimester)*  

- *Liver disease or abnormal liver function*  

- Caution in *children under 1 year* (only use if clearly needed)

Side Effects:

- *Common*:

  - Abdominal pain, nausea

  - Headache, dizziness

  - Temporary hair thinning

- *Rare/Serious*:

  - Elevated liver enzymes

  - Bone marrow suppression (neutropenia, pancytopenia)

  - Allergic reactions

  - Retinal damage (in ocular cysticercosis)

*Note:* Monitor LFTs during prolonged use.

Dosage:

- *For intestinal worms*:  

  - *400 mg once* (adults & children >2 years)

- *200 mg once* (children 1–2 years)

- *Neurocysticercosis*:  

  - 15 mg/kg/day in 2 divided doses for 8–30 days

- *Hydatid disease*:  

  - 10–15 mg/kg/day in 2 divided doses for 28-day cycles (with 14-day breaks between cycles)

- *Take with fatty meal* to enhance absorption in systemic infections.

Brand Names:

- *Zentel* (GSK)  

- *Alworm*  

- *Wormin*  

- *Alzental*  

- *Alzole*  

- *Eskazole*

Price:

- *Pakistan*: PKR 15–60 per 400 mg tablet  

- *India*: INR 5–20 per tablet  

- *International*: 0.50–2 per tablet (generic)

Conclusion:

Albendazole is a *safe, effective, and affordable* option for treating a variety of parasitic infections. Its role in *public health deworming programs* is vital, particularly in endemic regions. Though generally well-tolerated, *long-term or high-dose therapy* requires monitoring for liver function and blood counts.