Albendazole is a broad spectrum antiparasitic that exhibits vemicidal, ovicidal and lavicidal activity in animal and human studies. The results of studies with benzimidazole anthelminitics using sensitive and resistant strains were consistent with tubuline binding being the primary mechanism of action for all drugs in this class
Albendazole is poorly absorbed from the gastrointestinal tract due to its low aqueous solubility, albendazole concentrations are negligible or undetectable in plasma, as it is readily converted to the sulfoxide metabolite prior to reaching systemic circulation. The systemic antihelmintic activity has been attributed to the primary metabolite-albendazole sulfoxide. Oral bioavailability appears to be enhanced when albendazole is co-administered with a fatty meal, as evidenced by higher plasma concentrations of albendazole-sulfoxide, as compaired to fasted state.
Maximum plasma concentrations (Cmax) of albendazole sulfoxide are typically achieved 2 to 5 hours after dosing and are on average 1.31 mcg/ml (range 0.46 to 1.58 mcg/ml) following oral doses of albendazole (400mg). The mean apparent terminal elimination half-life of albendazole sulfoxide typically ranges from 8-12 hours. Albendazole sulfoxide is widely distributed throughout the body including into the bile and CSF.
Albendazole is rapidly converted in the liver to the primary metabolite, albendazole sulfoxide which is further metabolized to albendazole sulfone and other primary oxidative metabolites that have been identified in human urine. Urinary excretion of albendazole sulfoxide is a minor elimination pathway with less than 1% of the dose recovered in the urine. Biliary elimination presumably accounts for a portion of elimination as evidenced by biliary concentration of albendazole sulfoxide similar to those achieved in plasma. Following single dose administration of 200 to 300 mg (approximately 10mg/kg), in children aged 6 to 13 years with hydatid disease, albendazole sulfoxide pharmacokinetics were similar to those observed in adults.
Albendazole is effective in the treatment of single and mixed intestinal nematode infestations such as ascariasis, enterobias, ancylostomiasis and trichuriasis. It is also used in treatment of tapeworm infections like Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm) and Hymenolepis nana (dwarf tapeworm). Albendazole is also used in the treatment of Echinococcus granulosus (Hydatid cyst), Neurocysticerosis filariasis, cutaneous larva migrains, toxocariasis and cysticercosis
Womiban (albendazole) is contraindicated in patients with known hypersensitivity to the albendazole class of compounds or any of the components of Womiban
Rare fatalities associated with the use of albendazole have been reported due to granulocytopenia or pancytopenia. Blood counts should be monitored at the beginning of 28 days cycle of therapy and every 2 weeks, while on therapy with albendazole. Albendazole should not be used in pregnant women, excerpt in clinical circumstances where no alternative management is appropriate.
“Patient should not become pregnant for at least one month following cessation of albendazole therapy. If a patient becomes pregnant while taking this drug, albendazole should be immediately discontinued”
Patients being treated for neurocysticercosis should receive appropriate steroid and anticonvulsant therapy as required.
Pregnancy and lactation
There are no adequate and well-controlled studies of ablendazole administration in pregnant women. Albendazole should be used in pregnancy only if the potential benefits justify the risks to the foetus. Caution should be exercised when albendazole is administered to a nursing mother.
Use in children
No significant problems have been encountered in patients as young as one year when treated with albendazole and the efficacy appears to be similar to adults.
Use in elderly
Experience in patients 65 years of age or older is limited. No problem associated with an older population have been observed.
At usual dosages side effects are generally restricted to GI tract such as transient abdominal pain and diarrhea. High doses as in hydatid cyst can cause side effects like allergic reactions, raised liver enzyme values, alopecia, bone marrow depression and raised serum amylase values.
Albendazole acts on the enzyme cytochrome p450. Hence it may increase the ophylline levels in the blood.