View source for Albendazole

{{Short description|Chemical compound}}
{{Use dmy dates|date=February 2025}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox drug
| Watchedfields      = changed
| verifiedrevid      = 477316402
| image              = Albendazole.svg
| image_class        = skin-invert-image
| alt                = 
| image2             = Albendazole-from-xtal-2007-3D-balls.png
| width2             = 250
| alt2               =

<!-- Clinical data  -->
| tradename          = Albenza, others
| Drugs.com          = {{drugs.com|monograph|albendazole}}
| MedlinePlus        = a610019
| DailyMedID         = Albendazole
| pregnancy_AU       = D
| routes_of_administration = [[Oral administration|By mouth]]
| ATC_prefix         = P02
| ATC_suffix         = CA03
| ATC_supplemental   = {{ATCvet|P52|AC11}}

| legal_AU           = S4
| legal_CA           = Rx-only
| legal_UK           = POM
| legal_US           = Rx-only
| legal_US_comment   = (for humans; veterinary suspension and paste are both OTC)<ref name=plumb />

<!-- Pharmacokinetic data -->
| bioavailability    = <5%<ref name = MSR/>
| protein_bound      = 70%<ref name = MSR/>
| metabolism         = [[Liver]]<ref name = MSR/>
| elimination_half-life = 8–12 hours<ref name=MSR/>
| excretion          = [[Bile duct]] (humans)<br />Kidney (ruminants)

<!-- Identifiers -->
| IUPAC_name = methyl [6-(propylsulfanyl)-1''H''-benzimidazol-2-yl]carbamate
| CAS_number_Ref     = {{cascite|correct|??}}
| CAS_number         = 54965-21-8
| PubChem            = 2082
| DrugBank_Ref       = {{drugbankcite|correct|drugbank}}
| DrugBank           = DB00518
| ChemSpiderID_Ref   = {{chemspidercite|correct|chemspider}}
| ChemSpiderID       = 1998
| UNII_Ref           = {{fdacite|correct|FDA}}
| UNII               = F4216019LN
| KEGG_Ref           = {{keggcite|correct|kegg}}
| KEGG               = D00134
| ChEBI_Ref          = {{ebicite|correct|EBI}}
| ChEBI              = 16664
| ChEMBL_Ref         = {{ebicite|correct|EBI}}
| ChEMBL             = 1483
| NIAID_ChemDB       = 007895

<!-- Chemical data -->
| C                  = 12
| H                  = 15
| N                  = 3
| O                  = 2
| S                  = 1
| smiles             = CCCSc2ccc1nc(NC(=O)OC)[nH]c1c2
| StdInChI_Ref       = {{stdinchicite|correct|chemspider}}
| StdInChI           = 1S/C12H15N3O2S/c1-3-6-18-8-4-5-9-10(7-8)14-11(13-9)15-12(16)17-2/h4-5,7H,3,6H2,1-2H3,(H2,13,14,15,16)
| StdInChIKey_Ref    = {{stdinchicite|correct|chemspider}}
| StdInChIKey        = HXHWSAZORRCQMX-UHFFFAOYSA-N
| melting_point      = 208
| melting_high       = 210
}}

<!-- Definition and medical uses -->
'''Albendazole''' is a broad-spectrum [[antihelmintic]] and [[antiprotozoal]] agent of the [[benzimidazole]] type.<ref name=AHFS2015/> It is used for the treatment of a variety of [[intestinal parasite infection]]s, including [[ascariasis]], [[pinworm infection]], [[hookworm infection]], [[trichuriasis]], [[strongyloidiasis]], [[taeniasis]], [[clonorchiasis]], [[opisthorchiasis]], [[cutaneous larva migrans]], [[giardiasis]], and [[gnathostomiasis]], among other diseases.<ref name=AHFS2015>{{cite web|title=Albendazole|url=https://www.drugs.com/monograph/albendazole.html|publisher=The American Society of Health-System Pharmacists|access-date=18 August 2015|website=Drugs.com|url-status=live|archive-url=https://web.archive.org/web/20150923232451/http://www.drugs.com/monograph/albendazole.html|archive-date=23 September 2015 }}</ref>

<!-- Side effects and mechanism -->
Common side effects include [[nausea]], abdominal pain, and [[headache]].<ref name=AHFS2015/> Rare but potentially serious side effects include [[bone marrow suppression]] which usually improves on discontinuing the medication. [[Hepatitis|Liver inflammation]] has been reported and those with prior liver problems are at greater risk.<ref name=AHFS2015/> It is [[pregnancy category]] D in Australia, meaning it may cause harm if taken by pregnant women.<ref name=AHFS2015/><ref>{{cite web |title=Prescribing medicines in pregnancy database |url=https://www.tga.gov.au/products/medicines/find-information-about-medicine/prescribing-medicines-pregnancy-database |author=Australian Government |access-date=22 April 2014 |date=3 March 2014 |url-status=live |archive-url=https://web.archive.org/web/20140408040902/http://www.tga.gov.au/hp/medicines-pregnancy.htm |archive-date=8 April 2014 }}</ref>

<!-- History, society and culture -->
Albendazole was developed in 1975.<ref>{{cite book |title=Neonatal Formulary: Drug Use in Pregnancy and the First Year of Life |date=2014 |publisher=John Wiley & Sons |isbn=978-1-118-81959-3 |page=64 |url=https://books.google.com/books?id=VOLhBQAAQBAJ&pg=PA64 |url-status=live |archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=VOLhBQAAQBAJ&pg=PA64 |archive-date=8 September 2017 }}</ref> It is on the [[WHO Model List of Essential Medicines|World Health Organization's List of Essential Medicines]].<ref name="WHO23rd">{{cite book | vauthors = ((World Health Organization)) | title = The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023) | year = 2023 | hdl = 10665/371090 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | id = WHO/MHP/HPS/EML/2023.02 | hdl-access=free }}</ref> Albendazole is available in a [[fixed-dose combination]] with [[ivermectin]].<ref>{{cite web | title=Ivermectin/Albendazole - opinion on medicine for use outside EU | website=[[European Medicines Agency]] (EMA) | date=30 January 2025 | url=https://www.ema.europa.eu/en/opinion-medicine-use-outside-EU/human/ivermectin-albendazole | access-date=16 February 2025}}</ref>

==Medical uses==
Albendazole is an effective treatment for:
* [[Flatworm]]s
** [[Clonorchiasis]]<ref>{{Cite web|url=https://www.cdc.gov/parasites/clonorchis/treatment.html|title=CDC - Clonorchis - Treatment|website=[[Centers for Disease Control and Prevention|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}}</ref>
** [[Fasciolosis]]<ref name=AHFS2015 />
** [[Opisthorchiasis]]<ref>{{Cite web|url=https://www.cdc.gov/dpdx/opisthorchiasis/tx.html|title=Opisthorchiasis - Treatment Information|website=[[Centers for Disease Control and Prevention|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}}</ref>
** [[Cestoda|Cestodes]] (tapeworms), as an alternative to [[praziquantel]] or [[niclosamide]] for adult [[Taenia saginata|beef tapeworms]] and as an alternative to praziquantel for [[Taenia solium|pork tapeworms]].<ref name=tripathi>{{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 }}</ref> It is also given for infections by ''[[Taenia crassiceps|T.&nbsp;crassiceps]]''.<ref name=wu>{{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 }}</ref> 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.<ref name=yaffe-aranda>{{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 }}</ref>
*** [[Cysticercosis]]<ref name="who_mpi_1">{{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|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}}</ref> (especially [[neurocysticercosis]]), which is caused by the larval form of the pork tapeworm<ref name=AHFS2015 /> (i.e. albendazole is the drug of choice for larval pork tapeworms, but not adult pork tapeworms).<ref name=tripathi /> Old cysts are not affected.<ref name=yaffe-aranda />
*** [[Echinococcosis]]<ref name="who_mpi_1"/><ref name="pmid12667231">{{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 }}</ref> of the liver, lung, and peritoneum (caused by the larval form of the [[Echinococcus granulosus|dog tapeworm]], or of the alveoli (caused by ''[[Echinococcus multilocularis|E.&nbsp;multilocularis]]'') when surgical excision is not possible.<ref name=AHFS2015 /> Alveolar and cystic echinococcosis may require lifelong treatment with albendazole, which only prevents the parasites from growing and reproducing rather than killing them.<ref name=turner-horton>{{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}}</ref>
* [[Nematode]]s
** [[Anatrichosoma|Anatrichosomiasis]]<ref>{{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}}</ref>
** [[Angiostrongyliasis]]<ref>{{Cite web|url=https://www.cdc.gov/parasites/angiostrongylus/health_professionals/index.html|title=CDC - Angiostrongylus - Resources for Health Professionals|website=[[Centers for Disease Control and Prevention|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}}</ref>
** [[Anisakiasis]]<ref>{{Cite web|url=https://www.cdc.gov/parasites/anisakiasis/health_professionals/index.html|title=CDC - Anisakiasis - Resources for Health Professionals|website=[[Centers for Disease Control and Prevention|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}}</ref>
** [[Ascariasis]], which can be cured with a single dose of albendazole.<ref name="who_mpi_2">{{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|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}}</ref><ref name=sweet-gibbs>{{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 }}</ref>
** Baylisascariasis, caused by the [[Baylisascaris procyonis|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.<ref>{{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}}</ref>{{Unreliable medical source|date=May 2024}} [[Corticosteroid]]s are sometimes added in cases of eye and CNS infections.<ref name=AHFS2015 />
** [[Pinworm infection]]<ref name="who_mpi_2"/>
** [[Filariasis]]; since albendazole's disintegration of the [[microfilaria]]e ("pre-larva") can cause an allergic reaction, [[antihistamine]]s 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|''Loa loa'' filariasis]] as an adjunct or replacement to diethylcarbamazine.<ref name=AHFS2015 /><ref name=yaffe-aranda /> Albendazole has an embryotoxic effect on ''[[Loa loa]]'' adults and thus slowly reduces microfilaremia.<ref name=sweet-gibbs />
** [[Gnathostomiasis]] when caused by ''[[Gnathostoma spinigerum]].''<ref name=AHFS2015 /> 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.<ref name=turner-horton />
** [[Gongylonema pulchrum|Gongylonemiasis]]<ref name=AHFS2015 />
** Hepatic capillariasis caused by ''[[Capillaria hepatica]]''<ref name=Sawamura>{{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 }}</ref>
** [[Hookworm infection]]s,<ref name="who_mpi_2"/> including [[cutaneous larva migrans]] caused by hookworms of genus ''[[Ancylostoma]]''. A single dose of albendazole is sufficient to treat intestinal infestations by [[Ancylostoma duodenale|''A.&nbsp;duodenale'']] or ''[[Necator americanus]]''.<ref name=AHFS2015 /><ref name=sweet-gibbs />
** [[Intestinal capillariasis]],<ref name="who_mpi_2"/> as an alternative to [[mebendazole]]<ref name=AHFS2015 />
** [[Mansonelliasis]] when caused by ''[[Mansonella perstans]]''. Albendazole is effective against adult worms but not against the immature microfilariae.<ref name=turner-horton />
** [[Oesophagostomum]]iasis, when caused by ''Oesophagostomum bifurcum''<ref name=AHFS2015 />
** [[Strongyloidiasis]],<ref name="who_mpi_2" /> as an alternative to ivermectin or [[Tiabendazole|thiabendazole]].<ref name=AHFS2015 /><ref name=gouma>{{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 }}</ref> Albendazole can be given with diethylcarbamazine to lower microfilaremia levels.<ref name=sweet-gibbs />
** [[Toxocariasis]], also called "visceral larva migrans", when caused by the dog roundworm ''[[Toxocara canis]]'' or cat roundworm ''[[Toxocara cati|T.&nbsp;catis]]''. Corticosteroids can be added in severe cases, and surgery might be required to repair secondary damage.<ref name=AHFS2015 />
** [[Trichinosis]], when caused by ''[[Trichinella spiralis]]''<ref name=tripathi /> or ''T.&nbsp;pseudospiralis''. Albendazole has a similar efficacy to thiabendazole, but fewer side effects.<ref name=turner-horton /> 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.<ref name=yaffe-aranda />
** [[Trichostrongylus|Trichostrongyliasis]], as an alternative to [[Pyrantel|pyrantel pamoate]].<ref name=AHFS2015 /><ref name="who_mpi_2"/> A single dose is sufficient for treatment.<ref name=yaffe-aranda />
** [[Trichuriasis]] (whipworm infection),<ref name="who_mpi_2"/> sometimes considered as an alternative to mebendazole<ref name=AHFS2015 /><ref name=tripathi /> and sometimes considered to be the drug of choice. Only a single dose of albendazole is needed.<ref name=sweet-gibbs /> It can also be given with ivermectin.<ref name=finch>{{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}}</ref>
* [[Giardiasis]], as an alternative or adjunct to [[metronidazole]], especially in children<ref name=AHFS2015 /><ref name=who-hiv>{{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|archive-url=https://web.archive.org/web/20150829220338/http://apps.who.int/medicinedocs/en/d/Js2215e/9.2.html|archive-date=29 August 2015}}</ref>
* [[Microsporidiosis]], including ocular microsporidiosis caused by ''Encephalitozoon hellem'' or ''E.&nbsp;cuniculi'', when combined with topical [[fumagillin]]<ref name=AHFS2015 /><ref name=who-hiv />
* [[Granulomatous amoebic encephalitis]], when caused by the amoeba ''[[Balamuthia mandrillaris]]'', in combination with [[miltefosine]] and [[fluconazole]]<ref name="wu"/>
* [[Arthropod]]s
** [[Crusted scabies]], when combined with topical [[crotamiton]] and [[salicylic acid]]<ref name=wu />
** [[Head lice infestation]], though ivermectin is much better<ref name=wu />
** [[Myiasis|Intestinal myiasis]]<ref>{{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 }}</ref>

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.<ref>{{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 }}</ref>

=== Ivermectin/albendazole ===
When co-administered, ivermectin and albendazole act in synergy.<ref name="EMA PR 20250131" /> Ivermectin targets the parasite's nervous and muscular systems, causing paralysis, while albendazole disrupts the parasite's metabolism and [[microtubule]]s<ref name="EMA PR 20250131" />  by targeting [[tubulin]] polymerization.<ref>{{Cite journal | vauthors = Baksheeva VE, La Rocca R, Allegro D, Derviaux C, Pasquier E, Roche P, Morelli X, Devred F, Golovin AV, Tsvetkov PO | title = NanoDSF Screening for Anti-tubulin Agents Uncovers New Structure–Activity Insights | journal = Journal of Medicinal Chemistry | date = 2025 | doi = 10.1021/acs.jmedchem.5c01008 }}</ref> This dual approach immobilizes and kills the parasite and improves the treatment's effectiveness.<ref name="EMA PR 20250131" />

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.<ref name="EMA PR 20250131">{{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.</ref> 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.<ref name="EMA PR 20250131" /> 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]]''.<ref name="EMA PR 20250131" /> Ivermectin/albendazole is also indicated for the treatment of microfilaraemia (the presence of worm larvae in the blood) in people with lymphatic filariasis.<ref name="EMA PR 20250131" /> 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.<ref name="EMA PR 20250131" /> 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.<ref name="EMA PR 20250131" />

==Contraindications==
[[Hypersensitivity]] to the benzimidazole class of compounds contraindicates its use.<ref name="who_mpi_2" />

==Side effects==
[[File:Taenia solium cyst.jpg|thumb|Close-up of a pork tapeworm cyst. Destruction of these cysts can cause inflammation.]]
The most common side effects of albendazole are experienced by over 10% of people and include [[headache]] and abnormal liver function.<ref name="MSR" /> Elevation of [[liver enzymes]] occurs in 16% of patients receiving treatment specifically for hydatid disease and goes away when treatment ends.<ref name="yaffe-aranda" /><ref name=dailymed>{{Cite web|url=https://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}}</ref> Liver enzymes usually increase to two to four times the normal levels (a mild to moderate increase).<ref name="farrar">{{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}}</ref> 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 [[Cysticercus|cysticerci]] (tapeworm larvae), which causes acute inflammation.<ref name="jung">{{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 }}</ref> Fewer than 1% of people get [[hypersensitivity]] reactions such as rashes and hives, [[leukopenia]]s (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]].<ref name="MSR" /><ref>{{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 }}</ref>

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.<ref name="dailymed" /> Treating hydatid disease can also unmask undiagnosed neurocysticercosis.<ref name="dailymed" /> People receiving albendazole for the treatment of neurocysticercosis can have neurological side effects such as [[seizure]]s, increased intracranial pressure, and [[Focal neurologic signs|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.<ref name="dailymed" /> Those being treated for retinal neurocysticercosis can face [[retina]]l damage if they are not first checked for ocular cysticeri, since changes to existing lesions in the eye by albendazole can cause permanent blindness.<ref name="yaffe-aranda" />

===Pregnancy===
Albendazole is a [[pregnancy category|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 [[Teratology|teratogenic]],<ref name="drugs.com-pregnancy">{{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 }}</ref><ref name="parasitipedia-ricobendazole">{{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}}</ref> albendazole has been found to be safe in humans during the second and third trimesters.<ref name=papich>{{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}}</ref><ref name=briggs>{{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}}</ref> It can, however, possibly cause infantile [[Dermatitis|eczema]] when given during pregnancy.<ref name="wu-et-al">{{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 }}</ref>

In pregnant dogs, albendazole use has led to puppies with reduced weight and with [[Cleft lip and cleft palate|cleft palates]]. Birds have lower rates of laying eggs and hatching when given albendazole.<ref name=parasitipedia-toxicity>{{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 }}</ref>

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.<ref name="drugs.com-pregnancy" /><ref name=wiebe>{{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}}</ref>

==Overdose==
Because of its low solubility, albendazole often cannot be absorbed in high enough quantities to be toxic.<ref name=jung /> The oral [[median lethal dose|LD<sub>50</sub>]] of albendazole in rats was found to be 2,500&nbsp;mg/kg.<ref name=parasitipedia-ricobendazole /> It takes 20 times the normal dose to kill a sheep, and 30 times the normal dose to kill cattle.<ref name=plumb>{{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}}</ref> 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.{{medical citation needed|date=November 2024}} There is no specified antidote.<ref name=parasitipedia-toxicity />

== Interactions ==

The antiepileptics [[carbamazepine]], [[phenytoin]], and [[phenobarbital]] lower the plasma concentration and [[biological half-life|half-life]] of the sulfoxide metabolite's  (''R'')-(+)-enantiomer.<ref name="pmid12021623">{{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 }}</ref>

{| class="wikitable floatright"
|+ Antiepileptics and pharmacokinetics<br /> of albendazole sulfoxide<ref name=finch />
|-
! Drug !! Change in [[Area under the curve (pharmacokinetics)|AUC]] !! Change in [[Cmax (pharmacology)|C<sub>max</sub>]]
|-
| Carbamazepine || 49% decrease || 50–63% decrease
|-
| Phenobarbital || 61% decrease || 50–63% decrease
|-
| Phenytoin || 66% decrease || 50–63% decrease
|}

The antacid [[cimetidine]] heightens [[serum (blood)|serum]] albendazole concentrations, increases the half-life of albendazole, and doubles the levels of the sulfoxide metabolite in bile.<ref>{{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 }}</ref><ref name=dailymed /> It was originally thought to work by increasing albendazole [[bioavailability]] directly; however, it is now known that cimetidine inhibits the breakdown of the sulfoxide by interfering with [[CYP3A4]].<ref name=turner-horton /> The half-life of the sulfoxide metabolite thus increases from 7.4 hours to 19 hours.<ref name=bennett>{{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 }}</ref> This might be a helpful interaction on more severe cases, because it boosts the [[potency (pharmacology)|potency]] of albendazole.<ref name="pmid8192515">{{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 }}</ref> Paradoxically, cimetidine also inhibits the absorption of albendazole by reducing gastric acidity.<ref name=bennett />

Several other interactions exist. [[Corticosteroid]]s increase the [[Steady state (chemistry)|steady-state]] plasma concentration of the sulfoxide;<ref name=yaffe-aranda /> [[dexamethasone]], for example, can increase the concentration by 56% by inhibiting the elimination of the sulfoxide.<ref name=dailymed /><ref name=jung /> The anti-parasitic [[praziquantel]] increases the maximum plasma concentration of the sulfoxide by 50%,<ref name=dailymed /> and the anti-parasitic [[levamisole]] increases the [[Area under the curve (pharmacokinetics)|AUC]] (total drug exposure) by 75%.<ref name=finch /> [[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 [[Cmax (pharmacology)|maximum concentration]] of albendazole in the plasma as well as the AUC.<ref name=bennett />

==Pharmacology==
[[File:Microtubule structure.png|thumb|A microtubule is composed of polymers of α- and β-tubulin.]]

===Mechanism of action===
{{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 [[Tubulin#β-Tubulin|β-tubulin]], thus inhibiting its polymerization or assembly into [[microtubule]]s (it binds much better to the β-tubulin of parasites than that of mammals).<ref name=AHFS2015 /><ref name=dailymed /> 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 fiber]]s needed for cell division, which in turn blocks egg production and development; existing eggs are prevented from hatching.<ref name=turner-horton /><ref>{{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}}</ref> Cell motility, maintenance of cell shape, and intracellular transport are also disrupted.<ref name=riviere>{{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 }}</ref> 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]].<ref name=plumb /><ref name="parasitipedia-toxicity" /><ref name=waller-simpson>{{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}}</ref> 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.<ref name=dailymed /> 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.<ref name="Landmann-2019">{{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 | article-number = 7.2.25 | s2cid = 96448885 | pmc = 11590423 }}</ref> Elimination of ''Wolbachia'' from these filarial nematodes generally results in either death or sterility of the host nematode.<ref name="pmid12684759">{{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 }}</ref>

===Pharmacokinetics===
To target intestinal parasites, which is the most common indication for prescription, albendazole is taken on an empty stomach to stay within the gut.<ref>{{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}}</ref>

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.<ref name=dayan/>

The absorption also largely depends on [[gastric acid|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.<ref name=gouma /> Generally, the absorption in the GI tract is poor due to albendazole's low solubility in water.<ref name=AHFS2015 /> It is, however, better absorbed than other benzimidazole carbamates.<ref name=finch /> Food stimulates gastric acid secretion, lowering the pH and making albendazole more soluble and thus more easily absorbed.<ref name=bennett /> 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 [[Mucous membrane|mucus surface]] of the GI tract.<ref name="riviere" /><ref name=dayan>{{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 }}</ref>

Absorption is also affected by how much of the albendazole is degraded within the small intestine by metabolic enzymes in the villi.<ref name="gouma" />
[[File:Albendazole metabolism.svg|class=skin-invert-image|thumb|622x622px|General metabolism of albendazole and its sulfoxides]]
The pharmacokinetics of albendazole differ slightly between men and women: women have a lower oral [[Clearance (pharmacology)|clearance]] and [[volume of distribution]], while men have a lower serum peak concentration.<ref name="bennett" />

Albendazole undergoes very fast [[first-pass metabolism]] in all species, such that the unchanged drug is undetectable in plasma.<ref name="dayan" /> Most of it is oxidized into the sulfoxide metabolite, [[ricobendazole]],<ref name="parasitipedia-ricobendazole"/><ref>{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/Ricobendazole|title=Ricobendazole &#124; 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}}</ref> in the liver by [[cytochrome P450 oxidase]]s (CYPs) and a [[flavin-containing monooxygenase]] (FMO),<ref name="rawden">{{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 }}</ref> which was discovered later.<ref>{{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 }}</ref> In humans, the cytochrome P450 oxidases are thought to include [[CYP3A4]]<ref>{{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}}</ref> and [[CYP1A1]],<ref name="dayan" /> while those in the rats are thought to be CYP2C6 and CYP2A1.<ref name="capece" />

Oxidation to ricobendazole by FMO produces the (''R'')-(+) [[enantiomer]], while oxidation the cytochromes and by some enzymes in the gut epithelium produces (''S'')-(−). Different species produce the (''R'')-(+) and (''S'')-(−) enantiomers in different quantities; humans, dogs, and most other species<ref name="capece" /> produce the (''R'')-(+) enantiomer more (with the human AUC ratio being 80:20).<ref name="jung" /><ref name="bennett" /><ref name="dayan" /> 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.<ref name="capece">{{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 }}</ref><ref name="riviere" /> Some albendazole is also converted to hydroxyalbendazole, mainly by [[CYP2J2]].<ref name="wu-et-al" /><ref>{{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-access = subscription }}</ref>

For systemic parasites, albendazole acts as a [[prodrug]], while ricobendazole reaches systemic circulation and acts as the real antihelminthic.<ref name="turner-horton" /> Ricobendazole 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.<ref name="bennett" />

Ricobendazole is converted to the inactive albendazole sulfone by cytochrome P450 oxidases, thought to include CYP3A4<ref name="bennett" /> or [[CYP2C]].<ref name="turner-horton" /> Other inactive metabolites include: 2-aminosulfone, ω-hydroxysulfone, and β-hydroxysulfone.<ref name="rawden" /><ref name="jung" /> The major final metabolites that are excreted by humans are:<ref name="turner-horton" />
* methyl [5-(propylsulfonyl-1''H''-benzimidazol-2-yl)] carbamate,
* methyl [6-hydroxy 5-(n-propylsulfonyl)-1''H''-benzimidazol-2-yl)] carbamate,
* methyl [5-(n-propylsulfinyl)-1''H''-benzimidazol-2-yl)] carbamate,
* 5-(n-propylsulfonyl)-1''H''-benzimidazol-2-yl amine<!-- not sulfinyl -->, and
* 5-(n-propylsulfinyl)-1''H''-benzimidazol-2-yl amine.
There are also some minor hydroxylated sulfated or glucuronidated derivatives.<ref name="turner-horton" /> No unchanged albendazole is excreted, as it is metabolized too quickly.<ref name="MSR" />

In humans, the metabolites are excreted mostly in bile, with only a small amount being excreted in urine (less than 1%) and feces.<ref name=MSR >{{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}}</ref><ref name=turner-horton /> In ruminants, 60–70% of the metabolites are excreted in urine.<ref name=parasitipedia-toxicity />

Like all benzimidazoles, albendazole has no residual effect, and thus protects poorly against reinfestations.<ref name=parasitipedia-ricobendazole />

==History==
Albendazole, patented in 1975, was invented by Robert J. Gyurik and Vassilios J. Theodorides and assigned to [[Smith, Kline & French|SmithKline Corporation]].<ref>{{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]</ref><ref>{{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 }}</ref> It was introduced in 1977 as an antihelminthic for sheep in Australia, and was registered for human use in 1982.<ref name="yaffe-aranda" /><ref name=turner-horton />

==Society and culture==
[[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|thumb|Discarded bottles of albendazole distributed in Africa]]

===Economics===
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.<ref>{{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 }}</ref>

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.<ref>{{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 }}</ref>

===Brand names===
Brand names include: Albenza,<ref name=dailymed /> Alworm, Andazol, Eskazole, Noworm, Zentel, Alben-G, ABZ, Cidazole, Wormnil etc.

==Research==
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 [[binary fission|divide]]. Since ''[[Brugia malayi]]'' relies on symbiotic ''Wolbachia'', this would mean that albendazole is targeting both the worm and its essential symbiont.<ref name=Wolb>{{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 | article-number = e1002922 | date = September 2012 | pmid = 23028321 | pmc = 3447747 | doi = 10.1371/journal.ppat.1002922 | doi-access = free | title-link = doi }}</ref>

==Veterinary use==
Albendazole is mainly used in cattle and sheep, but has found some use in cats and dogs as well;<ref name=papich /> 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.<ref name=plumb />

{| class="wikitable"
|+ Albendazole use in animals<ref name=plumb /><ref name=papich /><ref name=bowman>{{cite book | vauthors = Bowman DD | title=Georgis' Parasitology for Veterinarians - E-Book | date=12 March 2014 | page=282 | url=https://books.google.com/books?id=7CFLBAAAQBAJ&pg=PA282 | publisher=Elsevier Health Sciences | isbn=978-1-4557-3988-2}}</ref><ref name=parasitipedia-use>{{cite web | vauthors = Junquera P | title=Albendazole for veterinary use on cattle, sheep, goats, pig poultry, dogs and cats against roundworms, tapeworms and liver flukes | work=Parasitipedia | access-date=3 August 2017 | date=11 February 2017 | url=http://parasitipedia.net/index.php?option=com_content&view=article&id=2513&Itemid=2786 | url-status=live | archive-url=https://web.archive.org/web/20170808153423/http://parasitipedia.net/index.php?option=com_content&view=article&id=2513&Itemid=2786 | archive-date=8 August 2017 }}</ref><ref name=dailymed-valbazen>{{cite web | publisher = US National Library of Medicine | title=VALBAZEN- albendazole suspension | work=DailyMed | access-date=2 August 2017 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=94cf5818-f27d-4374-87ad-54a2d9ce6ef1 | url-status=live | archive-url=https://web.archive.org/web/20170808193203/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=94cf5818-f27d-4374-87ad-54a2d9ce6ef1 | archive-date=8 August 2017 }}</ref>
! style="width: 20%;" |
! style="width: 15%;" | Cattle
! style="width: 15%;" | Sheep
! Others
|-
| colspan="4" | '''[[Platyhelminthes|Platyhelminthes (flatworms)]]'''
|-
| colspan="4" | [[Trematodes]]
|-
| style="padding-left: 2em;"| ''[[Dicrocoelium]]'' (liver flukes)
|| ''[[Dicrocoelium dendriticum|D. dendriticum]]'' (lancet liver fluke)<ref name=divers>{{cite book | vauthors = Divers TJ, Peek SF | title=Rebhun's Diseases of Dairy Cattle | date=2008 | page=238 | url=https://books.google.com/books?id=PbEWJrEtECIC&pg=PA238 | publisher=Elsevier Health Sciences | isbn=978-1-4160-3137-6 | url-status=live | archive-url=https://web.archive.org/web/20170908140627/https://books.google.com/books?id=PbEWJrEtECIC&pg=PA238 | archive-date=8 September 2017 }}</ref>
|| ''D. dendriticum''<ref name="parasitipedia-dosing" />
||
|-
| style="padding-left: 2em;"| ''[[Fasciola]]'' (liver flukes)
|| ''[[Fasciola hepatica|F. hepatica]]''
|| ''F. hepatica''
|| For ''F. hepatica'' and ''F. gigantica'' in people<ref name=AHFS2015 />
|-
| style="padding-left: 2em;"| ''[[Fascioloides]]'' (liver flukes)
|| ''F. magna''<ref name=divers />
|| ''F. magna''
|| Also for ''F. magna'' in South American [[camelids]] (ex. llama and alpaca)<ref name="parasitipedia-dosing" />
|-
| style="padding-left: 2em;" | ''[[Paragonimus]]'' (lung flukes)
|| —
|| —
|| For ''[[Paragonimus kellicotti|P. kellicotti]]'' in cats and dogs<ref name="parasitipedia-dosing" />
|-
| style="padding-left: 2em;" | ''Platynosomum''
|| —
|| —
|| For ''Platynosomum'' infections in cats
|-
| style="padding-left: 2em;" | ''Opisthorchiidae''
|| —
|| —
|| For ''Opisthorchiidae'' infections in cats
|-
| colspan="4" | [[Tapeworms|Cestodes (tapeworms)]]
|-
|style="padding-left: 2em;" | ''[[Echinococcus]]''
|| –
|| —
|| For ''Echinococcus'' cysts in horses and humans<ref name="parasitipedia-dosing" /><ref name=AHFS2015 />
|-
|style="padding-left: 2em;" | ''[[Moniezia]]''
|| ''[[Moniezia expansa|M. expansa]]''<br />''M. benedini''
|| ''M. expansa''<br />&nbsp;
||
|-
|style="padding-left: 2em;" | ''[[Taenia (flatworm)|Taenia]]''
|| ''[[Taenia saginata|T. saginata]]'' larvae
|| —
|| For ''T. saginata'', ''[[Taenia solium|T. solium]]'', and ''[[Taenia crassiceps|T. crassiceps]]'' in humans<ref name=tripathi /><ref name=wu /> and ''Taenia'' infections in dogs<ref>{{cite book | vauthors = Webster C | title=Clinical Pharmacology | date=March 2001 | pages=91, 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 }}</ref>
|-
|style="padding-left: 2em;" | ''Thysanosoma''
|| —
|| ''T. actinoides''
||
|-
| colspan="4" | '''[[Nematoda|Nematodes (roundworms)]]'''
|-
|''[[Ancylostoma]]''
|| —
|| –
|| For ''Ancylostoma'' infections in dogs, cats, and humans<ref name="parasitipedia-dosing" /><ref name=AHFS2015 />
|-
|''[[Bunostomum]]''
|| ''B. phlebotomum''
|| –
||
|-
| ''[[Capillaria (nematode)|Capillaria]]''
|| —
|| —
|| For causative agents of various forms of capillariasis in cats and dogs (including ''[[Capillaria philippinensis|C. philippinensis]]'', ''[[Capillaria hepatica|C. hepatica]]'', ''[[Capillaria aerophila|C. aerophila]]'', and ''[[Capillaria plica|C. plica]]'') and intestinal capillariasis (''C. philippinensis'') in humans.
|-
|''Chabertia''
|| —
|| ''[[Chabertia ovina|C. ovina]]''
||
|-
| ''Cooperia''
|| ''C. oncophora''<br />''C. punctata''
|| ''C. oncophora''<br />&nbsp;
|-
|''[[Dictyocaulus]]'' (lungworm)
|| ''[[Dictyocaulus#Dictyocaulus viviparus|D. viviparus]]''
|| ''D. filaria''
|| For ''D. amfieldi'' infections in horses
|-
| ''Filaroides'' (lungworm)
|| —
|| —
|| For ''F. hirthi'' and ''F. osleri'' in dogs
|-
| ''Haemonchus''
|| ''[[Haemonchus contortus|H. contortus]]'' <br /> ''H. placei''
|| ''H. contortus''<br />&nbsp;
||
|-
|''Marshallagia''
|| —
|| ''M. marshalli''
||
|-
|''Metastrongylus''
|| —
|| —
|| For ''M. apri'' in swine
|-
| ''Nematodirus''
|| ''N. spathiger''<br />''N. helvetianus''
|| ''N. spathiger''<br />''N. filicollis''
||
|-
| ''Parascaris''
|| —
|| —
|| For ''[[Parascaris equorum|P. equorum]]'' in horses<ref name=parasitipedia-use />
|-
| ''Ostertagia''
|| ''[[Ostertagia ostertagi|O.&nbsp;ostertagi]]''
|| ''[[Ostertagia circumcincta|O.&nbsp;circumcincta]]''
|| For ''O. bifurcum'' in humans
|-
| ''Oesophagostomum''
|| ''O. radiatum''
|| ''O.&nbsp;columbianum''
||
|-
| ''[[Strongyloides]]''
|| —
|| —
|| For ''[[Strongyloides stercoralis|S. stercoralis]]'' in dogs and humans<ref name=AHFS2015 /><ref name="parasitipedia-dosing" />
|-
| ''Strongylus''
|| —
|| —
|| For ''S. equinus'' in horses<ref name=parasitipedia-dosing />
|-
| ''[[Toxocara]]''
|| —
|| —
|| For ''[[Toxocara canis|T. canis]]'' infections in dogs<ref name="parasitipedia-dosing">{{cite web | vauthors = Junquera P | title=Albendazole dose for dogs, cats, horses, cattle, sheep, goats, swine and other domestic animals | work=Parasitipedia | access-date=3 August 2017 | date=8 December 2016 | url=http://parasitipedia.net/index.php?option=com_content&view=article&id=3675&Itemid=4072 | url-status=live | archive-url=https://web.archive.org/web/20170808153207/http://parasitipedia.net/index.php?option=com_content&view=article&id=3675&Itemid=4072 | archive-date=8 August 2017 }}</ref> and toxocariasis in humans (caused by ''T. canis'' and ''[[Toxocara cati|T. cati]]'')
|-
| ''Trichostrongylus''
|| ''T. axei''<br />''T.&nbsp;colubriformis''
|| ''T. axei''<br />''T.&nbsp;colubriformis''
|| For any ''Trichostrongylus'' infection in humans
|-
| ''[[Trichuris]]'' (whipworm)
|| Most species, but those usually found in cattle are:<ref name="parasitipedia-trichuris" /><br />''[[Trichuris discolor|T. discolor]]''<br />''T. globulosa'' <br />''[[Trichuris ovis|T. ovis]]''
|| Most species, but those usually found in sheep are:<ref name="parasitipedia-trichuris" /><br />''T. discolor''<br />''T. globulosa'' <br />''T. ovis''
|| Albendazole is also used for ''Trichuris'' infections in humans (usually ''[[Trichuris trichiura|T. trichiura]]'', causative agent of trichuriasis), dogs (usually ''[[Trichuris vulpis|T. vulpis]]'' and ''T. campanula''), cats (usually ''[[Trichuris serrata|T. serrata]]'' and ''T. campanula''), pigs (usually ''[[Trichuris suis|T. suis]]''), and other ruminants (same species as those found in cattle and sheep).<ref name="parasitipedia-trichuris">{{cite web | vauthors = Junquera P | title=''Trichuris spp.'', parasitic whipworms of dogs, cats and livestock - cattle, sheep, goats and pigs: Biology, prevention and control | work=Parasitipedia | access-date=3 August 2017 | date=12 December 2016 | url=http://parasitipedia.net/index.php?option=com_content&view=article&id=2601&Itemid=2883 | url-status=live | archive-url=https://web.archive.org/web/20170808153735/http://parasitipedia.net/index.php?option=com_content&view=article&id=2601&Itemid=2883 | archive-date=8 August 2017 }}</ref>
|-
| colspan="4" | '''Other'''
|-
| ''Encephalitozoon''
|| —
|| —
|| For ''[[Encephalitozoon cuniculi|E. cuniculi]]'' infections (microsporidiosis) in humans and rabbits
|-
| ''[[Giardia]]''
|| ''[[Giardia lamblia|G. lamblia]]'' (causative agent of [[giardiasis]])
|| —
|| Also treats giardiasis in humans, dogs, and small mammals
|-
| ''[[Leishmania]]''
|| —
|| —
|| Treats [[leishmaniasis]], caused by various species of ''Leishmania'', in dogs
|}

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.<ref name=parasitipedia-toxicity /><ref>{{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 }}</ref> Side effects include anorexia in dogs and lethargy, depression, and anorexia in cats,<ref name=plumb /> with more than 10% of dogs and cats having anorexia.<ref name=wiebe /> 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.<ref name=wiebe /> 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.<ref name=papich /><ref name=bowman /> 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]].<ref name=webster>{{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 }}</ref>

It is extensively used for ruminant livestock in [[Latin America]].<ref name=parasitipedia-ricobendazole /> 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;<ref name=plumb /><ref name=papich /> 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) is administered by subcutaneous injection.{{citation needed|date=August 2017}}

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

===Meat===
{{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''&nbsp;''μg/kg.

There is a 27-day cattle [[withdrawal time]] for meat.<ref name=papich />

== References ==
{{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:Propylthio compounds]]