Albendazole is a benzimidazole anthelmintic, active against most nematodes and some cestodes. It is used in the treatment of intestinal nematode infections and in higher doses in the treatment of hydatid disease. Albendazole exhibits vermicidal, ovicidal, and larvicidal activity. The principal mode of action of Albendazole is its inhibitory effect on tubulin polymerization, which results in the loss of cytoplasmic microtubules.

Albendazole is a broad spectrum anthelmintic. Albendazole exhibits vermicidal, ovicidal and larvicidal activities. The drug is thought to exert its anthelmintic effect by blocking glucose uptake in the susceptible helminths, thereby depleting the energy level until it becomes inadequate for survival. Immobilization is followed by the parasite. These events may be a consequence of the binding and subsequent inhibition of parasite tubulin polymerization by Albendazole and its metabolites, although the drug also binds to human tubulin. Albendazole is extensively metabolized, probably in the liver. Albendazole is poorly absorbed from the gastrointestinal tract but rapidly undergoes extensive first-pass metabolism. The principal metabolite albendazole sulphoxide has anthelmintic activity and a plasma half-life of about 8.5 hrs. It is excreted in the urine together with other metabolites.

Albendazole is indicated in single and mixed infestations of-

• Hookworm (Ancylostoma, Necator)
• Roundworm (Ascaris)
• Threadworm (Enterobius)
• Whipworm (Trichuris)
• Strongyloides
• Tapeworm
• Opisthorchi
• Hydatid.

Adults & children over 2 years:

• 400 mg (1 tablet or 10 ml suspension) as a single dose in cases of Enterobius vermicularis, Trichuris trichiura, Ascaris lumbricoides, Ancylostoma duodenale and Necator americanus.
• In cases of strongyloidiasis or taeniasis, 400 mg (1 tablet or 10 ml suspension) daily should be given for 3 consecutive days. If the patient is not cured on follow-up after three weeks, a second course of treatment is indicated. 

Children of 1-2 years: Recommended dose is a single dose of 200 mg (5 ml suspension).

Children under 1 year: Not recommended.

In Hydatid disease (Echinococcosis):

• Albendazole is given by mouth with meals in a dose of 400 mg twice daily for 28 days for patients weighing over 60 kg.
• A dose of 15 mg/kg body weight daily in two divided doses (to a maximum total daily dose of 800 mg) is used for patients weighing less than 60 kg.
• For cystic echinococcosis, the 28 days course may be repeated after 14 days without treatment, to a total of 3 treatment cycles.
• For alveolar echinococcosis, cycles of 28 days of treatment followed by 14 days without treatment, may need to continue for months or years.
• In giardiasis, 400 mg (1 tablet or 10 ml suspension) once daily for five days is used.

Neonates: Albendazole is not normally used in neonates.

Children: Reduction of the dose from 400 mg to 200 mg may be indicated in children weighing less than 10 kg but there are no grounds for a general reduction in dosage to children.

Pregnant woman: Albendazole should not be given during pregnancy or women thought to be pregnant. No information is available on placental transfer.

Concurrent disease: There is no evidence to suggest that dose should be altered in renal, hepatic or cardiac failure.

Gastrointestinal disturbances, headache, dizziness, changes in liver enzymes, rarely reversible alopecia; rash, fever, blood disorders including leucopenia and pancytopenia reported; allergic shock if cyst leakage; convulsion and meningism in cerebral disease.

Pregnancy & Lactation

US FDA Pregnancy category of Albendazole is C. So, Albendazole should be avoided in pregnancy and lactation unless the potential benefits to the other outweigh the possible risks to the fetus.

Precautions & Warnings

Blood counts and liver function tests before treatment and twice during each cycle; breastfeeding; exclude pregnancy before starting treatment. Albendazole should only be used in the treatment of Echinococcosis if there is constant medical supervision with regular monitoring of serum-transaminase concentrations and of leucocyte and platelet counts