|Systematic (IUPAC) name|
|Pregnancy cat.||D (AU) C (US)|
|Legal status||Prescription Only (S4) (AU) ℞-only (CA) POM (UK) ℞-only (US)|
|ATC code||P02 QP52|
|Mol. mass||265.333 g/mol|
|(what is this?)|
Albendazole, marketed as Albenza (United States), Eskazole, Zentel, Andazol, and Alworm, is a benzimidazole drug used for the treatment of a variety of parasitic worm infestations. It is marketed in the U.S. by Amedra Pharmaceuticals, and by GlaxoSmithKline in international markets. Albendazole was first discovered at the SmithKline Animal Health Laboratories in 1972. It is a broad-spectrum anthelmintic, effective against roundworms, tapeworms, and flukes of domestic animals and humans.
It is on the World Health Organization's List of Essential Medicines, a list of the most important medications needed in a basic health system.
It is effective first-line of treatment against:
In Africa, albendazole is being used to treat lymphatic filariasis as part of efforts to stop transmission of the disease. In sub-Saharan Africa, albendazole is used in conjunction with ivermectin, and elsewhere in the world, the medicine is used in combination with diethylcarbamazine.
Albendazole may cause abdominal pain, dizziness, headache, fever, nausea, vomiting, or temporary hair loss.
In rare cases, it may cause persistent sore throat, severe headache, seizures, vision problems, yellowing eyes or skin, dark urine, stomach pain, easy bruising, mental/mood changes, very stiff neck, or changes in amount of urine. Elevation of liver enzymes during treatment is a common side effect, but in rare cases, acute liver failure has been reported. Allergic reactions are also possible.
Rarely, albendazole has been reported to cause marrow suppression, agranulocytosis, or aplastic anemia, which may be permanent. The risk of developing this side effect seems to be increased in patients with liver disease, including echinococcal cysts. Because of this dangerous side effect, it is important to regularly monitor complete blood counts.
Antacids/histamine H2 antagonists
The drug cimetidine heightens serum albendazole concentrations, and increases the half life of albendazole. This might be a helpful interaction on more severe cases, because it boosts the potency of albendazole.
Hypersensitivity to the benzimidazole class of compounds contraindicates its use.
Do not take when pregnant, and do not become pregnant for one month after taking this drug; in Australia it is assigned class D. Pharmacokinetic studies have shown that trace amounts of albendazole appears in semen. Given this potential for teratogenicity, the manufacturers advise that the male sexual partner should also use adequate protections.
Mechanism of action
As a vermicidal, albendazole causes degenerative alterations in the intestinal cells of the worm by binding to the colchicine-sensitive site of tubulin, thus inhibiting its polymerization or assembly into microtubules. The loss of the cytoplasmic microtubules leads to impaired uptake of glucose by the larval and adult stages of the susceptible parasites, and depletes their glycogen stores. Degenerative changes occur in the endoplasmic reticulum, the mitochondria of the germinal layer, and the subsequent release of lysosome.
Albendazole has been used as an anthelmintic and for control of flukes in a variety of animal species, including cattle, sheep, goats, swine, camels, dogs, cats, elephants, poultry, and others. In many countries, it is very commonly used for ruminant livestock. For use in livestock, albendazole is marketed by Zoetis (formerly Pfizer Animal Health) in numerous countries (including the United States and Canada) as Valbazen in oral suspension and paste formulations; by Interchemie in the Netherlands and elsewhere as Albenol-100; by Channelle Animal Health Ltd. in the United Kingdom as Albex; by Ravensdown in New Zealand as Albendazole; etc. Although most formulations are administered orally, Ricomax (ricobendazole, or albendazole sulfoxide) is administered by subcutaneous injection.
Labeled usage (with regard to host species, dosage, withdrawal intervals, reproductive or lactational status, etc.) varies among nations. The US label for Valbazen oral suspension provides examples of some considerations in albendazole use in animals. It specifies dosage of 10 mg of albendazole per kg livemass for cattle and goats; 7.5 mg per kg livemass for sheep. With an albendazole concentration of 113.6 mg/ml in the suspension, these dosages are equivalent to 4 ml and 3 ml of suspension, respectively, per 100 pounds of body weight. Minimum intervals between administration and slaughter for food are 27 days (cattle) and 7 days (sheep and goats). This anthelmintic is not approved for use in female dairy cattle of breeding age or lactating does . The US label indicates that albendazole is not to be administered to female cattle during the first 45 days of pregnancy or for 45 days after removal of bulls; or to ewes or does in the first 30 days of pregnancy or for 30 days after removal of rams or bucks.
The limitations relating to early pregnancy are due to a limited period during which teratogenic effects may occur. Summarized research data relating to the durations of these preslaughter and early pregnancy periods when albendazole should not be administered are found in US FDA NADA 110-048 (cattle) and 140-934 (sheep). Some data and inferences regarding goats are found in US FDA Supplemental NADA 110-048 (approved January 24, 2008).
Maximum residue limits (MRLs) for albendazole in food, adopted by the FAO/WHO Codex Alimentarius in 1993, are 5000, 5000, 100, and 100 micrograms/kg for kidney, liver, fat and muscle, respectively, and 100 micrograms/l for milk. For analysis purposes, MRLs of various nations may pertain to concentration of a marker substance which has been correlated with concentrations of the administered substance and its metabolized products. For example, in Canada, the marker substance specified by Health Canada is albendazole-2-aminosulfone, for which the MRL in liver of cattle is 200 micrograms per kg.
Since 2010, the U.S. price of albendazole has increased by >4000% to over US$100 per 200-mg tablet. Amedra Pharmaceuticals is the U.S. distributor. GlaxoSmithKline retains distribution rights in all markets outside the U.S. The international wholesale price is typically less than US$0.05 per 200-mg tablet. In 2013, GlaxoSmithKline donated 763 million albendazole tablets for the treatment and prevention of parasitic infections in developing countries, bringing the total to over 4 billion tablets donated since 1998.
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- MedicineNet article
- Albenza description at RxList