albendazole

Albendazole is an effective treatment for:

• Flatworms
• Clonorchiasis{{Cite web|url=https://www.cdc.gov/parasites/clonorchis/treatment.html|title=CDC - Clonorchis - Treatment|website=CDC|date=20 February 2018|access-date=6 March 2024|archive-date=25 February 2024|archive-url=https://web.archive.org/web/20240225135643/https://www.cdc.gov/parasites/clonorchis/treatment.html|url-status=dead}}
• Fasciolosis
• Opisthorchiasis{{Cite web|url=https://www.cdc.gov/dpdx/opisthorchiasis/tx.html|title=Opisthorchiasis - Treatment Information|website=CDC - DPDx|date=29 November 2013|access-date=7 September 2015|archive-date=13 September 2015|archive-url=https://web.archive.org/web/20150913135607/http://www.cdc.gov/dpdx/opisthorchiasis/tx.html|url-status=dead}}
• Cestodes (tapeworms), as an alternative to praziquantel or niclosamide for adult beef tapeworms and as an alternative to praziquantel for pork tapeworms.{{cite book | vauthors = Tripathi KD | title=Essentials of Medical Pharmacology | date=30 September 2013 | page=850 | url=https://books.google.com/books?id=FfG8AQAAQBAJ&pg=PA850 | publisher=JP Medical Ltd | isbn=978-93-5025-937-5 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=FfG8AQAAQBAJ&pg=PA850 | archive-date=8 September 2017 }} It is also given for infections by T. crassiceps.{{cite book | vauthors = Wu JJ | title=Comprehensive Dermatologic Drug Therapy E-Book | date=18 October 2012 | page=137 | url=https://books.google.com/books?id=Tqpsm5WKKlcC&pg=PA137 | publisher=Elsevier Health Sciences | isbn=978-1-4557-3801-4 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=Tqpsm5WKKlcC&pg=PA137 | archive-date=8 September 2017 }} 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.{{cite book | vauthors = Yaffe SJ, Aranda JV | title=Neonatal and Pediatric Pharmacology: Therapeutic Principles in Practice | date=2010 | pages=470–472 | url=https://books.google.com/books?id=1e2-yggGeUIC&pg=PA470 | publisher=Lippincott Williams & Wilkins | isbn=978-0-7817-9538-8 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=1e2-yggGeUIC&pg=PA470 | archive-date=8 September 2017 }}
• Cysticercosis{{Cite web|url=http://apps.who.int/medicinedocs/en/d/Jh2922e/3.1.1.html|title=Helminths: Cestode (tapeworm) infection: Albendazole|date=1995|website=WHO Model Prescribing Information: Drugs Used in Parasitic Diseases - Second Edition|publisher=WHO|access-date=29 August 2015|url-status=dead|archive-url=https://web.archive.org/web/20150831034730/http://apps.who.int/medicinedocs/en/d/Jh2922e/3.1.1.html|archive-date=31 August 2015}} (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{{cite journal | vauthors = Horton J | title = Albendazole for the treatment of echinococcosis | journal = Fundamental & Clinical Pharmacology | volume = 17 | issue = 2 | pages = 205–212 | date = April 2003 | pmid = 12667231 | doi = 10.1046/j.1472-8206.2003.00171.x | s2cid = 221750495 }} 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.{{cite book | vauthors = Turner A, Horton J | title=Logan Turner's Diseases of the Nose, Throat and Ear | chapter=Albendazole | date=30 December 1987 | edition=10th | publisher=CRC Press | isbn=978-0-340-92767-0 | pages=2227–2239 | chapter-url=https://books.google.com/books?id=2-nwinRKtBQC&pg=PA2227}}
• Nematodes
• Anatrichosomiasis{{Cite web|url=https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html|title=Zoonotic Anatrichosomiasis in a Mother and Daughter|date=2014|website=National Center for Biotechnology Information|access-date=6 March 2024|archive-date=28 September 2023|archive-url=https://web.archive.org/web/20230928115351/https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html|url-status=live}}
• Angiostrongyliasis{{Cite web|url=https://www.cdc.gov/parasites/angiostrongylus/health_professionals/index.html|title=CDC - Angiostrongylus - Resources for Health Professionals|website=CDC|date=20 May 2020|access-date=2 May 2024|archive-date=2 May 2024|archive-url=https://web.archive.org/web/20240502115941/https://www.cdc.gov/parasites/angiostrongylus/health_professionals/index.html|url-status=dead}}
• Anisakiasis{{Cite web|url=https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html|title=CDC - Anisakiasis - Resources for Health Professionals|website=CDC|date=20 May 2020|access-date=6 March 2024|archive-date=28 September 2023|archive-url=https://web.archive.org/web/20230928115351/https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html|url-status=dead}}
• Ascariasis, which can be cured with a single dose of albendazole.{{Cite web|url=http://apps.who.int/medicinedocs/en/d/Jh2922e/3.2.1.html|title=Helminths: Intestinal nematode infection: Albendazole|date=1995|website=WHO Model Prescribing Information: Drugs Used in Parasitic Diseases - Second Edition|publisher=WHO|access-date=29 August 2015|url-status=dead|archive-url=https://web.archive.org/web/20150831034212/http://apps.who.int/medicinedocs/en/d/Jh2922e/3.2.1.html|archive-date=31 August 2015}}{{cite book | vauthors = Sweet RL, Gibbs RS | title=Infectious Diseases of the Female Genital Tract | date=2009 | pages=379, 382–383 | url=https://books.google.com/books?id=wuR_ngItU5oC&pg=PA379 | publisher=Lippincott Williams & Wilkins | isbn=978-0-7817-7815-2 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=wuR_ngItU5oC&pg=PA379 | archive-date=8 September 2017 }}
• 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.{{Cite web|url=https://abpharmacy.ca/articles/quick-thinking-saves-life|title=Quick thinking saves a life|date=2021|website=Alberta College of Pharmacy|access-date=19 June 2021|archive-date=21 June 2021|archive-url=https://web.archive.org/web/20210621034546/https://abpharmacy.ca/articles/quick-thinking-saves-life|url-status=live}}{{Unreliable medical source|date=May 2024}} 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{{cite journal | vauthors = Sawamura R, Fernandes MI, Peres LC, Galvão LC, Goldani HA, Jorge SM, de Melo Rocha G, de Souza NM | title = Hepatic capillariasis in children: report of 3 cases in Brazil | journal = The American Journal of Tropical Medicine and Hygiene | volume = 61 | issue = 4 | pages = 642–647 | date = October 1999 | pmid = 10548302 | doi = 10.4269/ajtmh.1999.61.642 | s2cid = 39515343 | doi-access = free | title-link = doi }}
• 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.{{cite book | vauthors = Gouma DJ | title=Update Gastroenterology 2004: New Developments in the Management of Benign Gastrointestinal Disorders | date=2004 | pages=144–145 | url=https://books.google.com/books?id=FfyJeSjyo-IC&pg=PA144 | publisher=John Libbey Eurotext | isbn=978-2-7420-0538-3 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=FfyJeSjyo-IC&pg=PA144 | archive-date=8 September 2017 }} 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.{{cite book | vauthors = Finch RG, Greenwood D, Whitley RJ, Norrby SR | title=Antibiotic and Chemotherapy E-Book | date=30 November 2010 | page=101 | url=https://books.google.com/books?id=DE4Mxc3aesEC&pg=PA101 | publisher=Elsevier Health Sciences | isbn=978-0-7020-4765-7}}
• Giardiasis, as an alternative or adjunct to metronidazole, especially in children{{Cite web|url=http://apps.who.int/medicinedocs/en/d/Js2215e/9.2.html|title=Drugs: Albendazole|date=1999|website=WHO Model Prescribing Information: Drugs Used in HIV-Related Infections|publisher=WHO|access-date=29 August 2015|url-status=dead|archive-url=https://web.archive.org/web/20150829220338/http://apps.who.int/medicinedocs/en/d/Js2215e/9.2.html|archive-date=29 August 2015}}
• 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{{cite journal | vauthors = Francesconi F, Lupi O | title = Myiasis | journal = Clinical Microbiology Reviews | volume = 25 | issue = 1 | pages = 79–105 | date = January 2012 | pmid = 22232372 | pmc = 3255963 | doi = 10.1128/CMR.00010-11 }}

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.{{cite web | title=Albenza New FDA Drug Approval | work=CenterWatch | access-date=8 August 2017 | url=http://www.centerwatch.com/drug-information/fda-approved-drugs/drug/126/albenza-albendazole | url-status=live | archive-url=https://web.archive.org/web/20170711183022/http://www.centerwatch.com/drug-information/fda-approved-drugs/drug/126/albenza-albendazole | archive-date=11 July 2017 }}

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. 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.{{cite web | title=New combination of medicines to treat parasitic worm infections | website=European Medicines Agency (EMA) | date=31 January 2025 | url=https://www.ema.europa.eu/en/news/new-combination-medicines-treat-parasitic-worm-infections | access-date=16 February 2025}} 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.

Hypersensitivity to the benzimidazole class of compounds contraindicates its use.

File:Taenia solium cyst.jpg

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.{{Cite web|url=http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e8941166-b77d-45aa-a6e8-04f1c0afd845|title=ALBENZA- albendazole tablet, film coated (NDC Code(s): 52054-550-22, 52054-550-28)|website=DailyMed|date=February 2013|access-date=9 October 2024|url-status=live|archive-url=https://web.archive.org/web/20150912165344/http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e8941166-b77d-45aa-a6e8-04f1c0afd845|archive-date=12 September 2015}} Liver enzymes usually increase to two to four times the normal levels (a mild to moderate increase).{{cite book|url=https://books.google.com/books?id=GTjRAQAAQBAJ&pg=PA807|title=Manson's Tropical Diseases E-Book | vauthors = Farrar J, Hotez PJ, Junghanss T, Kang G, Lalloo D, White NJ |date=26 October 2013|publisher=Elsevier Health Sciences|isbn=978-0-7020-5306-1|page=807}} 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.{{cite book | veditors=Singh G, Prabhakar S | vauthors=Jung H, Gonzáles-Esquivel DF | title=Taenia Solium Cysticercosis: From Basic to Clinical Science | chapter=Pharmacology of Anticysticeral Therapy | date=2002 | chapter-url=https://books.google.com/books?id=lCAd10-uTtQC&pg=PA368 | publisher=CABI | isbn=978-0-85199-839-8 | pages=368–371 | access-date=8 August 2017 | archive-date=14 January 2023 | archive-url=https://web.archive.org/web/20230114104521/https://books.google.com/books?id=lCAd10-uTtQC&pg=PA368 | url-status=live }} 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.{{cite web | title = Albenza (Albendazole) – Warnings and Precautions | url = http://www.druglib.com/druginfo/albenza/warnings_precautions/ | access-date = 9 March 2011 | url-status = live | archive-url = https://web.archive.org/web/20110302113148/http://www.druglib.com/druginfo/albenza/warnings_precautions/ | archive-date = 2 March 2011 }}

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.

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,{{cite web | title=Albendazole (Albenza) Use During Pregnancy | work=Drugs.com | access-date=4 August 2017 | url=https://www.drugs.com/pregnancy/albendazole.html | url-status=live | archive-url=https://web.archive.org/web/20170808113413/https://www.drugs.com/pregnancy/albendazole.html | archive-date=8 August 2017 }}{{Cite web|url=http://parasitipedia.net/index.php?option=com_content&view=article&id=2518&Itemid=2791|title=Ricobendazole = Albendazole Sulfoxide for Veterinary Use on Cattle, Sheep, Goats, Pig Poultry, Dogs and Cats against roundworms, tapeworms and liver flukes| vauthors = Junquera P |date=26 July 2015|website=Parasitipedia|access-date=21 October 2015|url-status=live|archive-url=https://web.archive.org/web/20160304093723/http://parasitipedia.net/index.php?option=com_content&view=article&id=2518&Itemid=2791|archive-date=4 March 2016}} albendazole has been found to be safe in humans during the second and third trimesters.{{cite book | vauthors = Papich MG | title=Saunders Handbook of Veterinary Drugs | chapter=Albendazole | location=St. Louis, Mo | date=2007 | edition=2nd | publisher=Saunders/Elsevier | isbn=978-1-4160-2888-8 | pages=8–9}}{{cite book | vauthors = Briggs GG, Freeman RK, Yaffe SJ | title=Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk | date=2011 | page=31 | url=https://books.google.com/books?id=OIgTE4aynrMC&pg=PA31 | publisher=Lippincott Williams & Wilkins | isbn=978-1-60831-708-0}} It can, however, possibly cause infantile eczema when given during pregnancy.{{cite journal | vauthors = Wu Z, Lee D, Joo J, Shin JH, Kang W, Oh S, Lee DY, Lee SJ, Yea SS, Lee HS, Lee T, Liu KH | title = CYP2J2 and CYP2C19 are the major enzymes responsible for metabolism of albendazole and fenbendazole in human liver microsomes and recombinant P450 assay systems | journal = Antimicrobial Agents and Chemotherapy | volume = 57 | issue = 11 | pages = 5448–5456 | date = November 2013 | pmid = 23959307 | pmc = 3811268 | doi = 10.1128/AAC.00843-13 | url = http://aac.asm.org/content/57/11/5448.full | url-status = live | archive-url = https://web.archive.org/web/20150904013040/http://aac.asm.org/content/57/11/5448.full | archive-date = 4 September 2015 }}

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.{{cite web | vauthors = Junquera P | title=Albendazole toxicity, poisoning, intoxication, overdose, antidote: safety summary for veterinary use on dogs, cats, cattle, sheep, goats, swine and poultry | publisher=Parasitipedia | access-date=24 July 2017 | url=http://parasitipedia.net/index.php?option=com_content&view=article&id=2697&Itemid=2960 | url-status=live | archive-url=https://web.archive.org/web/20170808113832/http://parasitipedia.net/index.php?option=com_content&view=article&id=2697&Itemid=2960 | archive-date=8 August 2017 }}

Albendazole sulfoxide 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.{{cite book | vauthors = Wiebe VJ | title=Drug Therapy for Infectious Diseases of the Dog and Cat | date=11 May 2015 | page=247 | url=https://books.google.com/books?id=jLM_CQAAQBAJ&pg=PA247 | publisher=John Wiley & Sons | isbn=978-1-118-55747-1}}

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.{{cite book | vauthors = Plumb DC | title=Plumb's Veterinary Drug Handbook | chapter=Albendazole | location=Stockholm, Wisconsin; Ames, Iowa | date=2011 | edition=7th | publisher=Wiley | isbn=978-0-470-95964-0 | pages=19–21}} 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.{{medcn|date=November 2024}} There is no specified antidote.

The antiepileptics carbamazepine, phenytoin, and phenobarbital lower the plasma concentration and half-life of albendazole sulfoxide's R(+) enantiomer.{{cite journal | vauthors = Lanchote VL, Garcia FS, Dreossi SA, Takayanagui OM | title = Pharmacokinetic interaction between albendazole sulfoxide enantiomers and antiepileptic drugs in patients with neurocysticercosis | journal = Therapeutic Drug Monitoring | volume = 24 | issue = 3 | pages = 338–345 | date = June 2002 | pmid = 12021623 | doi = 10.1097/00007691-200206000-00003 | url = https://www.researchgate.net/publication/11349600 | url-status = live | s2cid = 25194606 | archive-url = https://web.archive.org/web/20170808155134/https://www.researchgate.net/profile/Fabiola_Praca/publication/11349600_Pharmacokinetic_Interaction_Between_Albendazole_Sulfoxide_Enantiomers_and_Antiepileptic_Drugs_in_Patients_With_Neurocysticercosis/links/5639f9a308ae405111a54f49.pdf | archive-date = 8 August 2017 }}

The antacid cimetidine heightens serum albendazole concentrations, increases the half-life of albendazole, and doubles albendazole sulfoxide levels in bile.{{cite journal | vauthors = Schipper HG, Koopmans RP, Nagy J, Butter JJ, Kager PA, Van Boxtel CJ | title = Effect of dose increase or cimetidine co-administration on albendazole bioavailability | journal = The American Journal of Tropical Medicine and Hygiene | volume = 63 | issue = 5–6 | pages = 270–273 | date = December 2000 | pmid = 11421376 | doi = 10.4269/ajtmh.2000.63.270 | s2cid = 28550143 | doi-access = free | title-link = doi }} It was originally thought to work by increasing albendazole bioavailability directly; however, it is now known that cimetidine inhibits the breakdown of albendazole sulfoxide by interfering with CYP3A4. The half-life of albendazole sulfoxide thus increases from 7.4 hours to 19 hours.{{cite book | vauthors = Bennett JE, Dolin R, Blaser MJ | title=Principles and Practice of Infectious Diseases | date=28 August 2014 | page=520 | url=https://books.google.com/books?id=BseNCgAAQBAJ&pg=PA520 | publisher=Elsevier Health Sciences | isbn=978-1-4557-4801-3 | url-status=live | archive-url=https://web.archive.org/web/20161207205507/https://books.google.com/books?id=BseNCgAAQBAJ | archive-date=7 December 2016 }} This might be a helpful interaction on more severe cases, because it boosts the potency of albendazole.{{cite journal | vauthors = Wen H, Zhang HW, Muhmut M, Zou PF, New RR, Craig PS | title = Initial observation on albendazole in combination with cimetidine for the treatment of human cystic echinococcosis | journal = Annals of Tropical Medicine and Parasitology | volume = 88 | issue = 1 | pages = 49–52 | date = February 1994 | pmid = 8192515 | doi = 10.1080/00034983.1994.11812834 }} Paradoxically, cimetidine also inhibits the absorption of albendazole by reducing gastric acidity.

Several other interactions exist. Corticosteroids increase the steady-state plasma concentration of albendazole sulfoxide; dexamethasone, for example, can increase the concentration by 56% by inhibiting the elimination of albendazole sulfoxide. The anti-parasitic praziquantel increases the maximum plasma concentration of albendazole sulfoxide by 50%, and the anti-parasitic levamisole increases the AUC (total drug exposure) by 75%. Grapefruit inhibits the metabolism of albendazole within the intestinal mucosa. Finally, long-term administration of the antiretroviral ritonavir, which works as a CYP3A4 inhibitor, decreases the maximum concentration of albendazole in the plasma as well as the AUC.

File:Microtubule structure.png

{{Cleanup section|reason=should be sorted by target molecule, specifically into tubulin-related (intestines, spindle, shape) and unrelated parts|date=January 2021}}

As a vermicide, albendazole causes degenerative alterations in the intestinal cells of the worm by binding to the colchicine-sensitive site of β-tubulin, thus inhibiting its polymerization or assembly into microtubules (it binds much better to the β-tubulin of parasites than that of mammals). Albendazole leads to impaired uptake of glucose by the larval and adult stages of the susceptible parasites, and depletes their glycogen stores. Albendazole also prevents the formation of spindle fibers needed for cell division, which in turn blocks egg production and development; existing eggs are prevented from hatching.{{cite book | vauthors = St Georgiev V | title=Infectious Diseases in Immunocompromised Hosts | date=1997 | page=695 | url=https://books.google.com/books?id=73QOP6Xqh6EC&pg=PA695 | publisher=CRC Press | isbn=978-0-8493-8553-7}} Cell motility, maintenance of cell shape, and intracellular transport are also disrupted.{{cite book | vauthors = Riviere JE, Papich MG | title=Veterinary Pharmacology and Therapeutics | date=17 March 2009 | pages=1054, 1062 | url=https://books.google.com/books?id=ievLulSqwBAC&pg=PA1054 | publisher=John Wiley & Sons | isbn=978-0-8138-2061-3 | url-status=live | archive-url=https://web.archive.org/web/20160603202647/https://books.google.com/books?id=ievLulSqwBAC | archive-date=3 June 2016 }} At higher concentrations, it disrupts the helminths' metabolic pathways by inhibiting metabolic enzymes such as malate dehydrogenase and fumarate reductase, with inhibition of the latter leading to less energy produced by the Krebs cycle.{{cite book | vauthors = Waller DG, Sampson T | title=Medical Pharmacology and Therapeutics E-Book | date=4 June 2017 | page=616 | url=https://books.google.com/books?id=6b0tDwAAQBAJ&pg=PA616 | publisher=Elsevier Health Sciences | isbn=978-0-7020-7190-4}} Due to diminished ATP production, the parasite is immobilized and eventually dies.

Some parasites have evolved some resistance to albendazole by having a different set of amino acids constitute β-tubulin, decreasing the binding affinity of albendazole. Some parasites (especially filarial nematodes) live in symbiosis with Wolbachia, a type of intracellular parasite bacteria. In such cases the Wolbachia are necessary to the survival of the parasitic worms.{{cite journal | vauthors = Landmann F | title = The Wolbachia Endosymbionts | journal = Microbiology Spectrum | volume = 7 | issue = 2 | pages = 1–15 | date = March 2019 | pmid = 30953430 | doi = 10.1128/microbiolspec.bai-0018-2019 | publisher = American Society for Microbiology | veditors = Cossart P, Roy CR, Sansonetti P | s2cid = 96448885 | pmc = 11590423 }} Elimination of Wolbachia from these filarial nematodes generally results in either death or sterility of the host nematode.{{cite journal | vauthors = Hoerauf A, Mand S, Fischer K, Kruppa T, Marfo-Debrekyei Y, Debrah AY, Pfarr KM, Adjei O, Büttner DW | title = Doxycycline as a novel strategy against bancroftian filariasis-depletion of Wolbachia endosymbionts from Wuchereria bancrofti and stop of microfilaria production | journal = Medical Microbiology and Immunology | volume = 192 | issue = 4 | pages = 211–216 | date = November 2003 | pmid = 12684759 | doi = 10.1007/s00430-002-0174-6 | s2cid = 23349595 }}

To target intestinal parasites, which is the most common indication for prescription, albendazole is taken on an empty stomach to stay within the gut.{{cite book | vauthors = Boullata JI, Armenti VT | title=Handbook of Drug-Nutrient Interactions | date=17 March 2010 | page=306 | url=https://books.google.com/books?id=6MSRviXlDtAC&pg=PA306 | publisher=Springer Science & Business Media | isbn=978-1-60327-362-6}}

Oral absorption of albendazole varies among species, with 1–5% of the drug being successfully absorbed in humans, 20–30% in rats, and 50% in cattle.

The absorption also largely depends on gastric pH. People have varying levels of gastric pHs on empty stomachs, and thus absorption from one person to another can vary wildly when taken without food. Generally, the absorption in the GI tract is poor due to albendazole's low solubility in water. It is, however, better absorbed than other benzimidazole carbamates. Food stimulates gastric acid secretion, lowering the pH and making albendazole more soluble and thus more easily absorbed. Oral absorption is especially increased with a fatty meal, as albendazole dissolves better in lipids, allowing it to cross the lipid barrier created by the mucus surface of the GI tract.{{cite journal | vauthors = Dayan AD | title = Albendazole, mebendazole and praziquantel. Review of non-clinical toxicity and pharmacokinetics | journal = Acta Tropica | volume = 86 | issue = 2–3 | pages = 141–159 | date = May 2003 | pmid = 12745134 | doi = 10.1016/S0001-706X(03)00031-7 | series = Preparing to control Schistosomiasis and Soil-transmitted Helminthiasis in the Twenty-First Century }}

Absorption is also affected by how much of the albendazole is degraded within the small intestine by metabolic enzymes in the villi.

File:Albendazole metabolism.svg

The pharmacokinetics of albendazole differ slightly between men and women: women have a lower oral clearance and volume of distribution, while men have a lower serum peak concentration.

Albendazole undergoes very fast first-pass metabolism in all species, such that the unchanged drug is undetectable in plasma. Most of it is oxidized into albendazole sulfoxide (also known as ricobendazole and albendazole oxide{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/Ricobendazole|title=Ricobendazole | C12H15N3O3S (CID=83969)|date=17 October 2015|website=PubChem|publisher=National Center for Biotechnology Information|access-date=21 October 2015|url-status=live|archive-url=https://web.archive.org/web/20160306034517/http://pubchem.ncbi.nlm.nih.gov/compound/Ricobendazole|archive-date=6 March 2016}}) in the liver by cytochrome P450 oxidases (CYPs) and a flavin-containing monooxygenase (FMO),{{cite journal | vauthors = Rawden HC, Kokwaro GO, Ward SA, Edwards G | title = Relative contribution of cytochromes P-450 and flavin-containing monoxygenases to the metabolism of albendazole by human liver microsomes | journal = British Journal of Clinical Pharmacology | volume = 49 | issue = 4 | pages = 313–322 | date = April 2000 | pmid = 10759686 | pmc = 2014938 | doi = 10.1046/j.1365-2125.2000.00170.x }} which was discovered later.{{cite journal | vauthors = Fargetton X, Galtier P, Delatour P | title = Sulfoxidation of albendazole by a cytochrome P450-independent monooxygenase from rat liver microsomes | journal = Veterinary Research Communications | volume = 10 | issue = 4 | pages = 317–324 | date = July 1986 | pmid = 3739217 | doi = 10.1007/BF02213995 | s2cid = 24053943 }} In humans, the cytochrome P450 oxidases are thought to include CYP3A4{{cite book | vauthors = Stipanuk MH, Caudill MA | title=Biochemical, Physiological, and Molecular Aspects of Human Nutrition - E-Book | date=13 August 2013 | page=564 | url=https://books.google.com/books?id=XVNPAQAAQBAJ&pg=PA564 | publisher=Elsevier Health Sciences | isbn=978-0-323-26695-6}} and CYP1A1, while those in the rats are thought to be CYP2C6 and CYP2A1.

Oxidation to albendazole sulfoxide by FMO produces R(+) enantiomers, while oxidation the cytochromes and by some enzymes in the gut epithelium produce S(−). Different species produce the R(+) and S(−) enantiomers in different quantities; humans, dogs, and most other species produce the R(+) enantiomer more (with the human AUC ratio being 80:20). Compared to the S(−) enantiomer, the R(+) has greater pharmacological activity, lasts longer in the bloodstream, is found in higher concentrations in the infected host tissues, and is found in higher concentrations within the parasites themselves.{{cite journal | vauthors = Capece BP, Virkel GL, Lanusse CE | title = Enantiomeric behaviour of albendazole and fenbendazole sulfoxides in domestic animals: pharmacological implications | journal = Veterinary Journal | volume = 181 | issue = 3 | pages = 241–250 | date = September 2009 | pmid = 19124257 | doi = 10.1016/j.tvjl.2008.11.010 | hdl = 11336/95707 | hdl-access = free }} Some albendazole is also converted to hydroxyalbendazole, mainly by CYP2J2.{{cite journal | vauthors = Karkhanis A, Hong Y, Chan EC | title = Inhibition and inactivation of human CYP2J2: Implications in cardiac pathophysiology and opportunities in cancer therapy | journal = Biochemical Pharmacology | volume = 135 | pages = 12–21 | date = July 2017 | pmid = 28237650 | doi = 10.1016/j.bcp.2017.02.017 | s2cid = 43456597 | url = https://repository.hkbu.edu.hk/cgi/viewcontent.cgi?article=7373&context=hkbu_staff_publication | access-date = 7 September 2019 | archive-date = 27 April 2019 | archive-url = https://web.archive.org/web/20190427104456/https://repository.hkbu.edu.hk/cgi/viewcontent.cgi?article=7373&context=hkbu_staff_publication | url-status = dead | url-access = subscription }}

For systemic parasites, albendazole acts as a prodrug, while albendazole sulfoxide reaches systemic circulation and acts as the real antihelminthic. Albendazole sulfoxide is able to cross the blood–brain barrier and enter the cerebrospinal fluid at 43% of plasma concentrations; its ability to enter the central nervous system allows it to treat neurocysticercosis.

Albendazole sulfoxide is converted to the inactive albendazole sulfone by cytochrome P450 oxidases, thought to include CYP3A4 or CYP2C. Other inactive metabolites include: 2-aminosulfone, ω-hydroxysulfone, and β-hydroxysulfone. The major final metabolites that are excreted by humans are:

• methyl [5-(propylsulfonyl-1H-benzimidazol-2-yl)] carbamate,
• methyl [6-hydroxy 5-(n-propylsulfonyl)-1H-benzimidazole-2-yl)] carbamate,
• methyl [5-(n-propylsulfinyl)-1H-benzimidazole-2-yl)] carbamate,
• 5-(n-propylsulfonyl)-1H-benzimidazole-2-yl amine, and
• 5-(n-propysulfinyl)-1H-benzimidazole-2-yl amine.

There are also some minor hydroxylated sulfated or glucuronidated derivatives. No unchanged albendazole is excreted, as it is metabolized too quickly.

In humans, the metabolites are excreted mostly in bile, with only a small amount being excreted in urine (less than 1%) and feces.{{cite web|title=Albenza, (albendazole) dosing, indications, interactions, adverse effects, and more|work=Medscape Reference|publisher=WebMD|access-date=25 February 2014|url=http://reference.medscape.com/drug/albenza-albendazole-342648#showall|url-status=live|archive-url=https://web.archive.org/web/20140301073400/http://reference.medscape.com/drug/albenza-albendazole-342648#showall|archive-date=1 March 2014}} In ruminants, 60–70% of the metabolites are excreted in urine.

Like all benzimidazoles, albendazole has no residual effect, and thus protects poorly against reinfestations.

Albendazole, patented in 1975, was invented by Robert J. Gyurik and Vassilios J. Theodorides and assigned to SmithKline Corporation.{{cite patent|country=US|number=003915986|title=Methyl 5-propylthio-2-benzimidazolecarbamate|status=patent|pubdate=28 October 1975|fdate=|pridate=|gdate=|invent1=|inventor=Gyurkik, Robert; Theodorides, Vassilios|invent2=|assign1=SmithKline Corporation|assign2=|url=https://www.google.com/patents/US3915986|class=}} {{Webarchive|url=https://web.archive.org/web/20130724063646/http://www.google.com/patents/US3915986 |date=24 July 2013 }} [https://patents.google.com/patent/US3915986]{{cite patent|country=US|number=956499|title=Methods and compositions for producing polyphasic parasiticide activity using methyl 5-propylthio-2-benzimidazolecarbamate|status=patent|pubdate=11 May 1976|inventor=Gyurik R, Theodorides V|url=http://www.google.com/patents/US3956499|assign=SmithKline Corporation}} {{Webarchive|url=https://web.archive.org/web/20160319103246/http://www.google.com/patents/US3956499 |date=19 March 2016 }} [https://patents.google.com/patent/US3956499] {{Webarchive|url=https://web.archive.org/web/20240701042829/https://patents.google.com/patent/US3956499 |date=1 July 2024 }} It was introduced in 1977 as an antihelminthic for sheep in Australia, and was registered for human use in 1982.

File:US Navy 090308-N-0506A-393 Empty bottles of the de-worming medication albendazole are discarded in a box during a Combined Joint Task Force-Horn of Africa medical civil action project.jpg

The pharmaceutical company Amedra increased the price after purchasing the rights to the drug, instead of lowering it as generics are predicted to do, drawing criticism from patients' rights advocates.{{cite web | vauthors = Greene JA | title=Generic drug price gouging: How Shkreli and other monopolists cornered the market on essential medications | work=Slate | url=http://www.slate.com/articles/health_and_science/medical_examiner/2015/09/generic_drug_price_gouging_how_shkreli_and_other_monopolists_cornered_the.html | url-status=live | archive-url=https://web.archive.org/web/20151106171153/http://www.slate.com/articles/health_and_science/medical_examiner/2015/09/generic_drug_price_gouging_how_shkreli_and_other_monopolists_cornered_the.html | archive-date=6 November 2015 | date=23 September 2015 }}

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.{{cite journal | vauthors = Gustavsen KM, Bradley MH, Wright AL | title = GlaxoSmithKline and Merck: private-sector collaboration for the elimination of lymphatic filariasis | journal = Annals of Tropical Medicine and Parasitology | volume = 103 | issue = Suppl 1 | pages = S11–S15 | date = October 2009 | pmid = 19843393 | doi = 10.1179/000349809X12502035776478 | s2cid = 206837136 }}

Brand names include: Albenza, Alworm, Andazol, Eskazole, Noworm, Zentel, Alben-G, ABZ, Cidazole, Wormnil etc.

Albendazole and related compounds or metabolites like albendazole sulfone (ALB-SO2) exhibit antibacterial effects via an unknown, possibly FtsZ-related, mechanism. It inhibits division of Wolbachia and Mycobacterium tuberculosis, turning them into a long "filament" shape as they grow and fail to divide. Since Brugia malayi relies on symbiotic Wolbachia, this would mean that albendazole is targeting both the worm and its essential symbioant.{{cite journal | vauthors = Serbus LR, Landmann F, Bray WM, White PM, Ruybal J, Lokey RS, Debec A, Sullivan W | title = A cell-based screen reveals that the albendazole metabolite, albendazole sulfone, targets Wolbachia | journal = PLOS Pathogens | volume = 8 | issue = 9 | pages = e1002922 | date = September 2012 | pmid = 23028321 | pmc = 3447747 | doi = 10.1371/journal.ppat.1002922 | doi-access = free | title-link = doi }}

Albendazole is mainly used in cattle and sheep, but has found some use in cats and dogs as well; it is also used in ratite birds for flagellate parasites and tapeworms. It is also used off-label to treat endoparasites in goats and pigs.

Albendazole has been used as an antihelminthic and for control of flukes in a variety of animal species, including cattle, sheep, goats, swine, camels, dogs, cats, elephants, poultry, and others.{{cite book | vauthors = Fowler ME | title=Biology, Medicine, and Surgery of Elephants | date=2 October 2006 | page=174 | url=https://books.google.com/books?id=oCpiZA61tyQC&pg=PA174 | publisher=John Wiley & Sons | isbn=978-0-8138-0676-1 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=oCpiZA61tyQC&pg=PA174 | archive-date=8 September 2017 }} Side effects include anorexia in dogs and lethargy, depression, and anorexia in cats, with more than 10% of dogs and cats having anorexia. Of dogs and cats, 1–10% experience elevated liver enzymes, nausea, vomiting, and diarrhea. Less than 1% experience neutropenia or aplastic anemia, though these require a use of at least 5 days. While it is also associated with bone marrow suppression and toxicity in cats and dogs at high doses, albendazole has a higher margin of safety in other species. Thus, it is usually only prescribed in cats and dogs when an infection is present that is resistant to the commonly prescribed metronidazole and fenbendazole.{{cite book | vauthors = Webster C | title=Clinical Pharmacology | date=March 2001 | page=142 | url=https://books.google.com/books?id=NmR00leAkt8C&pg=PA142 | publisher=Teton NewMedia | isbn=978-1-893441-37-8 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=NmR00leAkt8C&pg=PA142 | archive-date=8 September 2017 }}

It is extensively used for ruminant livestock in Latin America. It is marketed for this purpose 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; and by Ravensdown in New Zealand (as Albendazole). Although most formulations are administered orally, Ricomax (ricobendazole, or albendazole sulfoxide) is administered by subcutaneous injection.{{citation needed|date=August 2017}}

Albendazole has greater bioavailability in ruminants: some albendazole sulfoxide, when released back into the rumen, is reduced to albendazole by the resident microbiota, with a preference of the (+) enantiomer being the substrate. Cats and dogs, having no rumen reservoir, sometimes need higher or more frequent doses as compared to ruminants. In dogs, albendazole sulfoxide is detectable in the plasma for less than 12 hours, but in sheep and goats, it remains at measurable levels for around three days.

{{more citations needed|section|date=August 2017}}

The limitations in 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 24 January 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 per kilogram of body weight (μg/kg) for kidney, liver, fat, and muscle, respectively, and 100 μg/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 μg/kg.

There is a 27-day cattle withdrawal time for meat.

{{reflist}}

{{Anthelmintics}}

{{Excavata antiparasitics}}

{{GlaxoSmithKline}}

{{Portal bar | Medicine}}

{{Authority control}}

Category:Anthelmintics

Category:Benzimidazoles

Category:Carbamates

Category:Drugs developed by GSK plc

Category:Thioethers

Category:World Health Organization essential medicines

Category:Wikipedia medicine articles ready to translate

Category:Propyl compounds