Albendazole is a broad-spectrum antihelmintic and antiprotozoal agent of the benzimidazole type. It is used for the treatment of a variety of intestinal parasite infections, including ascariasis, pinworm infection, hookworm infection, trichuriasis, strongyloidiasis, taeniasis, clonorchiasis, opisthorchiasis, cutaneous larva migrans, giardiasis, and gnathostomiasis, among other diseases.
Common side effects include nausea, abdominal pain, and headache. Rare but potentially serious side effects include bone marrow suppression which usually improves on discontinuing the medication. Liver inflammation has been reported and those with prior liver problems are at greater risk. It is pregnancy category D in Australia, meaning it may cause harm if taken by pregnant women.
Albendazole was developed in 1975. It is on the World Health Organization's List of Essential Medicines. Albendazole is available in a fixed-dose combination with ivermectin.
Medical uses Albendazole is an effective treatment for: Flatworms Clonorchiasis Fasciolosis Opisthorchiasis Cestodes (tapeworms), as an alternative to praziquantel or niclosamide for adult beef tapeworms and as an alternative to praziquantel for pork tapeworms. It is also given for infections by T. crassiceps. Though praziquantel is often better at treating tapeworm infections, albendazole is used more often in endemic countries due to being cheaper and having a broader spectrum. Cysticercosis (especially neurocysticercosis), which is caused by the larval form of the pork tapeworm (i.e. albendazole is the drug of choice for larval pork tapeworms, but not adult pork tapeworms). Old cysts are not affected. Echinococcosis of the liver, lung, and peritoneum (caused by the larval form of the dog tapeworm, or of the alveoli (caused by E. multilocularis) when surgical excision is not possible. Alveolar and cystic echinococcosis may require lifelong treatment with albendazole, which only prevents the parasites from growing and reproducing rather than killing them. Nematodes Anatrichosomiasis Angiostrongyliasis Anisakiasis Ascariasis, which can be cured with a single dose of albendazole. Baylisascariasis, caused by the raccoon roundworm. Albendazole can achieve good results (95–100% efficacy after a 10-day course of treatment) if treatment is initiated within 72 hours of ingestion of the egg-containing raccoon feces. Corticosteroids are sometimes added in cases of eye and CNS infections. Pinworm infection Filariasis; since albendazole's disintegration of the microfilariae ("pre-larva") can cause an allergic reaction, antihistamines or corticosteroids are sometimes added to treatment. In cases of lymphatic filariasis (elephantiasis) caused by Wuchereria bancrofti or Brugia malayi, albendazole is sometimes given as an adjunct to ivermectin or diethylcarbamazine in order to suppress microfilaremia. It can also be given for Loa loa filariasis as an adjunct or replacement to diethylcarbamazine. Albendazole has an embryotoxic effect on Loa loa adults and thus slowly reduces microfilaremia. Gnathostomiasis when caused by Gnathostoma spinigerum. Albendazole has a similar effectiveness to ivermectin in these cases, though it needs to be given for 21 days rather than the 2 days needed for ivermectin. Gongylonemiasis Hepatic capillariasis caused by Capillaria hepatica Hookworm infections, including cutaneous larva migrans caused by hookworms of genus Ancylostoma. A single dose of albendazole is sufficient to treat intestinal infestations by A. duodenale or Necator americanus. Intestinal capillariasis, as an alternative to mebendazole Mansonelliasis when caused by Mansonella perstans. Albendazole is effective against adult worms but not against the immature microfilariae. Oesophagostomumiasis, when caused by Oesophagostomum bifurcum Strongyloidiasis, as an alternative to ivermectin or thiabendazole. Albendazole can be given with diethylcarbamazine to lower microfilaremia levels. Toxocariasis, also called "visceral larva migrans", when caused by the dog roundworm Toxocara canis or cat roundworm T. catis. Corticosteroids can be added in severe cases, and surgery might be required to repair secondary damage. Trichinosis, when caused by Trichinella spiralis or T. pseudospiralis. Albendazole has a similar efficacy to thiabendazole, but fewer side effects. It works best when given early, acting on the adult worms in the intestine before they generate larva that can penetrate the muscle and cause a more widespread infection. Corticosteroids are sometimes added on to prevent inflammation caused by dying larva. Trichostrongyliasis, as an alternative to pyrantel pamoate. A single dose is sufficient for treatment. Trichuriasis (whipworm infection), sometimes considered as an alternative to mebendazole and sometimes considered to be the drug of choice. Only a single dose of albendazole is needed. It can also be given with ivermectin. Giardiasis, as an alternative or adjunct to metronidazole, especially in children Microsporidiosis, including ocular microsporidiosis caused by Encephalitozoon hellem or E. cuniculi, when combined with topical fumagillin Granulomatous amoebic encephalitis, when caused by the amoeba Balamuthia mandrillaris, in combination with miltefosine and fluconazole Arthropods Crusted scabies, when combined with topical crotamiton and salicylic acid Head lice infestation, though ivermectin is much better Intestinal myiasis
Though albendazole is effective in treating many diseases, it is only FDA-approved for treating hydatid disease caused by dog tapeworm larvae and neurocysticercosis caused by pork tapeworm larvae.
Ivermectin/albendazole When co-administered, ivermectin and albendazole act in synergy. Ivermectin targets the parasite's nervous and muscular systems, causing paralysis, while albendazole disrupts the parasite's metabolism and microtubules by targeting tubulin polymerization. This dual approach immobilizes and kills the parasite and improves the treatment's effectiveness.
In January 2025, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive scientific opinion for ivermectin/albendazole for the treatment of infections caused by several types of worm parasites including lymphatic filariasis, a neglected tropical disease. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. Ivermectin/albendazole is indicated for use in people aged five years of age or older, for the treatment of soil-transmitted helminth infections, caused by different types of intestinal parasitic worms, which are spread through soil contaminated by human feces in areas with poor sanitation. Among the worms responsible for these diseases are hookworms (Ancylostoma duodenale, Necator americanus), roundworms (Ascaris lumbricoides), whipworms (Trichuris trichiura) and a roundworm called Strongyloides stercoralis. Ivermectin/albendazole is also indicated for the treatment of microfilaraemia (the presence of worm larvae in the blood) in people with lymphatic filariasis. Lymphatic filariasis is a neglected tropical disease commonly known as elephantiasis, which impairs the lymphatic system and can lead to the abnormal enlargement of body parts, causing pain, severe disability and social stigma. Ivermectin/albendazole is indicated for the treatment of cases of lymphatic filariasis caused by Wuchereria bancrofti, a parasite which is responsible for 90% of cases worldwide.
Contraindications Hypersensitivity to the benzimidazole class of compounds contraindicates its use.
Side effects
The most common side effects of albendazole are experienced by over 10% of people and include headache and abnormal liver function. Elevation of liver enzymes occurs in 16% of patients receiving treatment specifically for hydatid disease and goes away when treatment ends. Liver enzymes usually increase to two to four times the normal levels (a mild to moderate increase). An estimated 1–10% of people experience abdominal pain, nausea or vomiting, dizziness or vertigo, increased intracranial pressure, meningeal signs, temporary hair loss, and fever. The headache, nausea, and vomiting are thought to be caused by the sudden destruction of cysticerci (tapeworm larvae), which causes acute inflammation. Fewer than 1% of people get hypersensitivity reactions such as rashes and hives, leukopenias (drop in white blood cell levels) such as agranulocytosis and granulocytopenia, thrombocytopenia (reduced platelet count), pancytopenia (drop in white blood cells, red blood cells, and platelets), hepatitis, acute liver failure, acute kidney injury, irreversible bone marrow suppression, and aplastic anemia.
Side effects can be different when treating for hydatid disease versus neurocysticercosis: for example, those being treated for the former are more likely to experience elevated liver enzymes and abdominal pain, while those being treated for the latter are more likely to experience headache. Treating hydatid disease can also unmask undiagnosed neurocysticercosis. People receiving albendazole for the treatment of neurocysticercosis can have neurological side effects such as seizures, increased intracranial pressure, and focal signs caused by the inflammatory reaction that occurs when parasites in the brain are killed. Steroids and anticonvulsants are often given with albendazole when treating neurocysticercosis to avoid these effects. Those being treated for retinal neurocysticercosis can face retinal damage if they are not first checked for ocular cysticeri, since changes to existing lesions in the eye by albendazole can cause permanent blindness.
Pregnancy Albendazole is a pregnancy class D drug in Australia. It is contraindicated in the first trimester of pregnancy, and should be avoided up to one month before conception. While studies in pregnant rats and rabbits have shown albendazole to be teratogenic, albendazole has been found to be safe in humans during the second and third trimesters. It can, however, possibly cause infantile eczema when given during pregnancy.
In pregnant dogs, albendazole use has led to puppies with reduced weight and with cleft palates. Birds have lower rates of laying eggs and hatching when given albendazole.
The sulfoxide metabolite is secreted into breast milk at around 1.5% of the maternal dose, though oral absorption is poor enough that it is unlikely to affect nursing infants.
Overdose Because of its low solubility, albendazole often cannot be absorbed in high enough quantities to be toxic. The oral LD50 of albendazole in rats was found to be 2,500 mg/kg. It takes 20 times the normal dose to kill a sheep, and 30 times the normal dose to kill cattle. Overdose affects the liver, testicles, and gastrointestinal tract (GI tract) the most. It can manifest with lethargy, loss of appetite, vomiting, diarrhea, intestinal cramps, dizziness, convulsions, and sleepiness. There is no specified antidote.
Interactions
The antiepileptics carbamazepine, phenytoin, and phenobarbital lower the plasma concentration and half-life of the sulfoxide metabolite's (R)-(+)-enantiomer.
+ Antiepileptics and pharmacokinetics of albendazole sulfoxide Drug Change in AUC Change in Cmax Carbamazepine 49% decrease 50–63% decrease Phenobarbital 61% decrease 50–63% decrease Phenytoin 66% decrease 50–63% decrease