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{{Short description|Anti-parasite medication}}
{{Use dmy dates|date=May 2025}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox drug
| Watchedfields = changed
| verifiedrevid = 464213440
| image = Praziquantel enantiomers labelled.svg
| image_class = skin-invert-image
| width = 300
| alt =
| imageL = (R)-praziquantel-from-xtal-3D-bs-17.png
| widthL = 150
| imageR = (S)-praziquantel-from-xtal-3D-bs-17.png
| widthR = 150


| pronounce = {{IPAc-en|ˌ|p|r|æ|z|ɪ|ˈ|k|w|ɒ|n|t|ɛ|l}}
| tradename = Biltricide
| Drugs.com = {{drugs.com|monograph|praziquantel}}
| MedlinePlus = a608048
| DailyMedID = Praziquantel
| pregnancy_AU = B1
| pregnancy_AU_comment =
| pregnancy_category =
| routes_of_administration = [[Oral administration|by mouth]]
| class =
| ATC_prefix = P02
| ATC_suffix = BA01
| ATC_supplemental = {{ATCvet|P52|AA01}} {{ATCvet|P52|AA51}}


| legal_AU = 
| legal_AU_comment =
| legal_BR = 
| legal_BR_comment =
| legal_CA = Rx-only
| legal_CA_comment = <ref>{{cite web | title=Product monograph brand safety updates | website=Health Canada | date=February 2024 | url=https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database/label-safety-assessment-update/product-monograph-brand-safety-updates.html | access-date=24 March 2024}}</ref>
| legal_DE = 
| legal_DE_comment =
| legal_NZ = 
| legal_NZ_comment =
| legal_UK = 
| legal_UK_comment =
| legal_US = Rx-only
| legal_US_comment = (human use),<br />OTC (veterinary use)
| legal_EU = Rx-only
| legal_EU_comment = <ref name="Prazivetin EPAR" /><ref name="Prazivetin PI" />
| legal_UN = 
| legal_UN_comment =
| legal_status = 


| bioavailability = Relatively small
| protein_bound =
| metabolism = [[Liver]]
| metabolites =
| onset =
| elimination_half-life = 0.8–1.5 hours (main metabolites: 4–5 hours)
| duration_of_action =
| excretion = [[Kidney]] (mainly)


| CAS_number_Ref = {{cascite|correct|??}}
| CAS_number = 55268-74-1
| PubChem = 4891
| IUPHAR_ligand =
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB01058
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 4722
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 6490C9U457
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D00471
| ChEBI =
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 976
| NIAID_ChemDB =
| PDB_ligand =
| synonyms = PZQ


| IUPAC_name = (''RS'')-2-(Cyclohexylcarbonyl)-1,2,3,6,7,11b-hexahydro-4''H''-pyrazino[2,1-''a'']isoquinolin-4-one
| C=19
| H=24
| N=2
| O=2
| SMILES = O=C4N2C(c1c(cccc1)CC2)CN(C(=O)C3CCCCC3)C4
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C19H24N2O2/c22-18-13-20(19(23)15-7-2-1-3-8-15)12-17-16-9-5-4-6-14(16)10-11-21(17)18/h4-6,9,15,17H,1-3,7-8,10-13H2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = FSVJFNAIGNNGKK-UHFFFAOYSA-N
| density =
| density_notes =
| melting_point = 136
| melting_high = 138
| melting_notes =
| boiling_point =
| boiling_notes =
| solubility =
| sol_units =
| specific_rotation =
}}


'''Praziquantel''', sold under the brandname '''Biltricide''' among others, is a [[medication]] used to treat a number of types of [[helminthiasis|parasitic worm infection]]s in mammals, birds, amphibians, reptiles, and fish.<ref name=AHFS2016/> In humans specifically, it is used to treat [[schistosomiasis]], [[clonorchiasis]], [[opisthorchiasis]], [[Taeniasis|tapeworm infection]]s, [[cysticercosis]], [[echinococcosis]], [[paragonimiasis]], [[fasciolopsiasis]], and [[fasciolosis]].<ref name=AHFS2016/> It should not be used for worm infections of the eye.<ref name=WHO2008>{{cite book | title = WHO Model Formulary 2008 | year = 2009 | isbn = 978-92-4-154765-9 | vauthors = ((World Health Organization)) | veditors = Stuart MC, Kouimtzi M, Hill SR | hdl = 10665/44053 | author-link = World Health Organization | publisher = World Health Organization | hdl-access=free | pages=88, 593 }}</ref> It is taken [[Oral administration|by mouth]].<ref name=AHFS2016>{{cite web|title=Praziquantel|url=https://www.drugs.com/monograph/praziquantel.html|publisher=The American Society of Health-System Pharmacists|access-date=8 December 2016|url-status=live|archive-url=https://web.archive.org/web/20161220223422/https://www.drugs.com/monograph/praziquantel.html|archive-date=20 December 2016}}</ref>


Side effects in humans may include poor coordination, abdominal pain, vomiting, headache, and allergic reactions.<ref name=WHO2008/> While it may be used during [[pregnancy]], it is not recommended for use during [[breastfeeding]].<ref name=WHO2008/> Praziquantel is in the [[anthelmintic]] class of medications.<ref name=AHFS2016/> It works partly by affecting the function of the worm's [[Sucker (zoology)|sucker]].<ref name=AHFS2016/>


Praziquantel was approved for medical use in the United States in 1982,<ref name=AHFS2016/> and in the European Union in April 2025.<ref name="Prazivetin EPAR" /><ref name="Prazivetin PI" /> 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>

==Medical uses==
Praziquantel is used to treat diseases caused by infection with several types of internal/gastrointestinal, and external parasites, including:
* [[Echinococcosis|Hydatid disease]] caused by infection of various organs with larval stages of tapeworms of the genus ''[[Echinococcus]]''
* [[Cysticercosis]] caused by infection of the brain and/or muscles with the eggs and larvae of the pork tapeworm ''[[Taenia solium]]'' (though it has been judged less effective than [[albendazole]] in treatment of [[neurocysticercosis]])<ref name="pmid18335068">{{cite journal | vauthors = Matthaiou DK, Panos G, Adamidi ES, Falagas ME | title = Albendazole versus praziquantel in the treatment of neurocysticercosis: a meta-analysis of comparative trials | journal = PLOS Neglected Tropical Diseases | volume = 2 | issue = 3 | article-number = e194 | date = March 2008 | pmid = 18335068 | pmc = 2265431 | doi = 10.1371/journal.pntd.0000194 | veditors = Carabin H | doi-access = free }}</ref>
* [[Taeniasis]] caused by intestinal infection with ''[[Taenia saginata]]'' and ''[[Taenia solium]]''<ref>{{Cite web|url=https://www.cdc.gov/parasites/taeniasis/health_professionals/index.html|title=CDC - Taeniasis - Resources for Health Professionals|website=[[Centers for Disease Control and Prevention|CDC]]|date=20 May 2020|access-date=2 May 2024}}</ref>
* [[Diphyllobothriasis]] caused by intestinal infection with ''[[Diphyllobothrium latum]]''<ref>{{Cite web|url=https://www.cdc.gov/parasites/diphyllobothrium/health_professionals/index.html|title=CDC - Diphyllobothrium - Resources for Health Professionals|website=[[Centers for Disease Control and Prevention|CDC]]|date=20 May 2020|access-date=2 May 2024}}</ref>
* [[Hymenolepiasis]] caused by ''[[Hymenolepis nana]]'' and ''[[Hymenolepis diminuta]]''<ref>{{Cite web|url=https://www.cdc.gov/parasites/hymenolepis/health_professionals/index.html|title=CDC - Hymenolepis - Resources for Health Professionals|website=[[Centers for Disease Control and Prevention|CDC]]|date=20 May 2020|access-date=2 May 2024}}</ref>
* [[Bertielliasis]] caused by intestinal infection with ''[[Bertiella studeri]]''<ref>{{Cite web|url=https://www.cdc.gov/dpdx/bertiella/tx.html|title=CDC - DPDx - Bertiella infection - Treatment Information|website=[[Centers for Disease Control and Prevention|CDC]]|date=29 November 2013|access-date=2 May 2024}}</ref>
* In dogs and cats, whose gastrointestinal tracts are infected with the tapeworms ''[[Dipylidium caninum]]'' or ''[[Taenia taeniaeformis]]'', respectively;<ref name=BYRDRTL>{{Citation|title=Drontal Data Sheet; Drontal Cat & Cat XL Film-coated Tablets, Bayer plc|page=2|publisher=Bayer plc, Animal Health Division|place=Newbury, England|url=https://www.drontal.com/static/drontal/DrontalCat&CatXLFilm-coatedTablets.pdf|access-date=23 September 2015|url-status=live|archive-url=https://web.archive.org/web/20150923085950/https://www.drontal.com/static/drontal/DrontalCat%26CatXLFilm-coatedTablets.pdf|archive-date=23 September 2015}}</ref><ref name=FCP>{{Cite book|title=Feline clinical parasitology| vauthors = Bowman DD, Hendrix CM, Lindsay DS, Barr SC |edition=First|year=2002|page=275|publisher=Iowa State University|place=Ames, Iowa|url=https://books.google.com/books?id=mvpsA9dGdpAC&q=%22toxocara+cati%22&pg=PA278|isbn=0-8138-0333-0|url-status=live|archive-url=https://web.archive.org/web/20170910151740/https://books.google.com/books?id=mvpsA9dGdpAC&pg=PA278&dq=%22toxocara+cati%22&hl=en&sa=X&ei=s-JpT7GjFYKviALbkrnNBQ&ved=0CD0Q6AEwAQ#v=onepage&q=%22toxocara%20cati%22&f=false|archive-date=10 September 2017}}</ref> praziquantel is also often used in fixed combination with [[pyrantel embonate]] against the roundworms ([[ascaris|ascarids]]): ''[[Toxocara cati]]'' and ''[[Toxascaris leonina]]''.<ref name=BYRDRTL /><ref name=FCP /> Praziquantel is also effective against ''[[Echinococcus multilocularis]]''.<ref name=BYRDRTL />
* [[Schistosomiasis]] caused by [[trematodes]] of the genus ''[[Schistosoma]]'':<ref name="pmid15642971">{{cite journal | vauthors = Tchuenté LA, Shaw DJ, Polla L, Cioli D, Vercruysse J | title = Efficacy of praziquantel against Schistosoma haematobium infection in children | journal = The American Journal of Tropical Medicine and Hygiene | volume = 71 | issue = 6 | pages = 778–782 | date = December 2004 | pmid = 15642971 | doi = 10.4269/ajtmh.2004.71.778 | doi-access = free }}</ref> As of 2005, praziquantel is the primary treatment for human [[schistosomiasis]], for which it is usually effective in a single dose.<ref name="SCP">{{Cite web | author=The Carter Center | title=Schistosomiasis Control Program | url=http://www.cartercenter.org/health/schistosomiasis/index.html | access-date=17 July 2008 | url-status=live | archive-url=https://web.archive.org/web/20080720091015/http://cartercenter.org/health/schistosomiasis/index.html | archive-date=20 July 2008 }}</ref>
* [[Clonorchiasis]] brought on by the Chinese liver fluke ''[[Clonorchis sinensis]]''<ref name="pmid17570980">{{cite journal | vauthors = Shen C, Kim J, Lee JK, Bae YM, Choi MH, Oh JK, Lim MK, Shin HR, Hong ST | title = Collection of Clonorchis sinensis adult worms from infected humans after praziquantel treatment | journal = The Korean Journal of Parasitology | volume = 45 | issue = 2 | pages = 149–152 | date = June 2007 | pmid = 17570980 | pmc = 2526309 | doi = 10.3347/kjp.2007.45.2.149 | url = http://www.parasitol.or.kr/kjp/abstracts/2007_149.html | archive-url = https://archive.today/20121220070503/http://www.parasitol.or.kr/kjp/abstracts/2007_149.html | archive-date = 20 December 2012 }}</ref>
* [[Opisthorchiasis]] brought on by the liver flukes ''[[Opisthorchis viverrini]]'' and ''[[Opisthorchis felineus]]''<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}}</ref>
* [[Paragonimiasis]] caused by infection with lung flukes, mostly of the species ''[[Paragonimus westermani]]''<ref>{{Cite web|url=https://www.cdc.gov/parasites/paragonimus/gen_info/faqs.html|title=CDC - Paragonimiasis - General Information - Frequently Asked Questions (FAQs)|date=19 April 2019|website=www.cdc.gov|language=en-us|access-date=2 October 2019}}</ref><ref>{{Cite web|url=https://www.cdc.gov/parasites/paragonimus/health_professionals/index.html|title=CDC - Paragonimiasis - Resources for Health Professionals|date=24 May 2019|website=www.cdc.gov|language=en-us|access-date=2 October 2019}}</ref>
* [[Fasciolopsiasis]] caused by the giant intestinal fluke ''[[Fasciolopsis buski]]''<ref name="pmid16150452">{{cite journal | vauthors = Mas-Coma S, Bargues MD, Valero MA | title = Fascioliasis and other plant-borne trematode zoonoses | journal = International Journal for Parasitology | volume = 35 | issue = 11–12 | pages = 1255–1278 | date = October 2005 | pmid = 16150452 | doi = 10.1016/j.ijpara.2005.07.010 }}</ref>
* [[Echinostomiasis]] caused by infection with intestinal flukes of the genus ''[[Echinostoma]]''<ref name="pmid35343418">{{cite journal | vauthors = Toledo R, Álvarez-Izquierdo M, Guillermo-Esteban J, Muñoz-Antoli C | title = Neglected food-borne trematodiases: echinostomiasis and gastrodiscoidiasis | journal = Parasitology| volume = 149 | issue = 10 | pages = 1319–1326 | date = March 2022 | pmid = 35343418 | doi = 10.1017/s0031182022000385 | doi-access = free | pmc = 10090775 }}</ref>
* [[Metagonimiasis]] caused by infection with intestinal flukes of the genus ''[[Metagonimus]]''<ref>{{cite journal | vauthors = Rim HJ, Chu DS, Lee JS, Joo KH, Won CY | title = [Anthelmintic Effects Of Various Drugs Against Metagonimiasis] | journal = Kisaengch'unghak Chapchi. The Korean Journal of Parasitology | volume = 16 | issue = 2 | pages = 117–122 | date = December 1978 | pmid = 12902772 | doi = 10.3347/kjp.1978.16.2.117 }}</ref>
* Heterophyiasis caused by the intestinal fluke ''[[Heterophyes heterophyes]]''<ref name="pmid3799097">{{cite journal | vauthors = Taraschewski H, Mehlhorn H, Bunnag D, Andrews P, Thomas H | title = Effects of praziquantel on human intestinal flukes (Fasciolopsis buski and Heterophyes heterophyes) | journal = Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Series A: Medical Microbiology, Infectious Diseases, Virology, Parasitology| volume = 262 | issue = 4 | pages = 542–550 | date = November 1986 | pmid = 3799097 | doi = 10.1016/s0176-6724(86)80148-1 }}</ref>
* Gastrodiscoidiasis caused by the intestinal fluke ''[[Gastrodiscoides|Gastrodiscoides hominis]]''<ref name="pmid35343418">{{cite journal | vauthors = Toledo R, Álvarez-Izquierdo M, Guillermo-Esteban J, Muñoz-Antoli C | title = Neglected food-borne trematodiases: echinostomiasis and gastrodiscoidiasis | journal = Parasitology| volume = 149 | issue = 10 | pages = 1319–1326 | date = March 2022 | pmid = 35343418 | doi = 10.1017/s0031182022000385 | doi-access = free | pmc = 10090775 }}</ref>

==Side effects==
The majority of side effects develop due to the release of the contents of the parasites as they are killed and the consequent host immune reaction. The heavier the parasite burden, the heavier and more frequent the side effects normally are.{{cn|date=February 2023}}
* Central nervous system (CNS): Frequently occurring side effects are [[dizziness]], [[headache]], and malaise. [[Drowsiness]], [[somnolence]], [[fatigue (physical)|fatigue]], and [[Vertigo (medical)|vertigo]] have also been seen. Almost all patients with cerebral [[cysticercosis]] experience CNS side effects related to the cell-death of the parasites (headache, worsening of pre-existing neurological problems, [[seizures]], [[arachnoiditis]], and [[meningism]]). These side effects may be life-threatening and can be reduced by coadministration of [[corticosteroid]]s. All patients with cerebral [[cysticercosis]] are strongly recommended to be hospitalized during treatment.
* Gastrointestinal tract: About 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. [[Diarrhea]] may develop and may be severe with colic. Sweating, fever, and sometimes bloody stools may occur together with diarrhea.
* Liver: Asymptomatic and transient increases of liver enzymes ([[Aspartate transaminase|AST]] and [[Alanine transaminase|ALT]]) are noted frequently (up to 27%). No case of symptomatic liver damage has been seen so far.
* Sensitivity reactions: [[Urticaria]], [[rash]], [[pruritus]] and [[eosinophilia]] in white blood cell counts
* Other locations/body as a whole: Lower back pain, myalgia, arthralgia, fever, sweating, various cardiac [[arrhythmias]], and [[hypotension]]

===Pregnancy===
The WHO states praziquantel is safe during pregnancy (although does not recommend use during the first trimester).<ref>{{cite web |url=https://www.who.int/schistosomiasis/strategy/en/ |archive-url=https://web.archive.org/web/20070617184031/http://www.who.int/schistosomiasis/strategy/en/ |archive-date=17 June 2007 |website=World Health Organisation: Schistosomiasis |access-date=4 March 2020|title=WHO } Guideline }}</ref><ref>{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK578392/pdf/Bookshelf_NBK578392.pdf |website=WHO (2022) "WHO Guideline on control and elimination of human schistosomiasis" ISBN 978-92-4-004160-8
|access-date=2 October 2024|title=WHO } Strategy }}</ref> Animal studies have failed to reveal evidence of fetal harm. Praziquantel is effective in reducing schistosomiasis during pregnancy.<ref>{{cite journal | vauthors = Tweyongyere R, Mawa PA, Emojong NO, Mpairwe H, Jones FM, Duong T, Dunne DW, Vennervald BJ, Katunguka-Rwakishaya E, Elliott AM | title = Effect of praziquantel treatment of Schistosoma mansoni during pregnancy on intensity of infection and antibody responses to schistosome antigens: results of a randomised, placebo-controlled trial | journal = BMC Infectious Diseases | volume = 9 | issue = 32 | article-number = 32 | date = March 2009 | pmid = 19296834 | pmc = 2666740 | doi = 10.1186/1471-2334-9-32 | doi-access = free }}</ref> Another trial found that treatment with praziquantel did not increase the rates of low birthweight, fetal death, or congenital anomalies.<ref>{{cite journal | vauthors = Olveda RM, Acosta LP, Tallo V, Baltazar PI, Lesiguez JL, Estanislao GG, Ayaso EB, Monterde DB, Ida A, Watson N, McDonald EA, Wu HW, Kurtis JD, Friedman JF | title = Efficacy and safety of praziquantel for the treatment of human schistosomiasis during pregnancy: a phase 2, randomised, double-blind, placebo-controlled trial | journal = The Lancet. Infectious Diseases | volume = 16 | issue = 2 | pages = 199–208 | date = February 2016 | pmid = 26511959 | pmc = 4752899 | doi = 10.1016/S1473-3099(15)00345-X }}</ref>

==Drug interactions==
The antibiotic [[rifampicin]] decreases plasma concentrations of praziquantel.<ref>{{cite journal | vauthors = Ridtitid W, Wongnawa M, Mahatthanatrakul W, Punyo J, Sunbhanich M | title = Rifampin markedly decreases plasma concentrations of praziquantel in healthy volunteers | journal = Clinical Pharmacology and Therapeutics | volume = 72 | issue = 5 | pages = 505–513 | date = November 2002 | pmid = 12426514 | doi = 10.1067/mcp.2002.129319 | s2cid = 30853881 }}</ref>

[[Carbamazepine]] and [[phenytoin]] are reported to reduce the bioavailability of praziquantel.<ref>{{cite journal | vauthors = Quinn DI, Day RO | title = Drug interactions of clinical importance. An updated guide | journal = Drug Safety | volume = 12 | issue = 6 | pages = 393–452 | date = June 1995 | pmid = 8527014 | doi = 10.2165/00002018-199512060-00005 | s2cid = 34890344 }}</ref> [[Chloroquine]] also reduces its bioavailability.<ref>{{cite journal | vauthors = Masimirembwa CM, Naik YS, Hasler JA | title = The effect of chloroquine on the pharmacokinetics and metabolism of praziquantel in rats and in humans | journal = Biopharmaceutics & Drug Disposition | volume = 15 | issue = 1 | pages = 33–43 | date = January 1994 | pmid = 8161714 | doi = 10.1002/bdd.2510150103 | s2cid = 45098166 }}</ref>

The drug [[cimetidine]] heightens praziquantel bioavailability.<ref>{{cite journal | vauthors = Metwally A, Bennett JL, Botros S, Ebeid F | title = Effect of cimetidine, bicarbonate and glucose on the bioavailability of different formulations of praziquantel | journal = Arzneimittel-Forschung | volume = 45 | issue = 4 | pages = 516–518 | date = April 1995 | pmid = 7779153 }}</ref><ref>{{cite journal | vauthors = Jung H, Medina R, Castro N, Corona T, Sotelo J | title = Pharmacokinetic study of praziquantel administered alone and in combination with cimetidine in a single-day therapeutic regimen | journal = Antimicrobial Agents and Chemotherapy | volume = 41 | issue = 6 | pages = 1256–1259 | date = June 1997 | pmid = 9174180 | pmc = 163896 | doi = 10.1128/AAC.41.6.1256 }}</ref>

==Mechanism of action==
The drug's mode of action is not exactly known at present, but experimental evidence indicates praziquantel increases the permeability of the membranes of schistosome cells towards calcium ions. The drug thereby induces contraction of the parasites' muscle, resulting in paralysis in the contracted state. The dying parasites are dislodged from their site of action in the host organism and may enter systemic circulation or may be destroyed by host immune reaction ([[phagocytosis]]). Additional mechanisms including focal disintegrations and disturbances of oviposition (laying of eggs) are seen in other types of sensitive parasites.{{cn|date=February 2023}}

Another hypothesis regarding the mechanism of action is that it interferes with [[adenosine]] uptake in worms.<ref>{{cite journal | vauthors = Angelucci F, Basso A, Bellelli A, Brunori M, Pica Mattoccia L, Valle C | title = The anti-schistosomal drug praziquantel is an adenosine antagonist | journal = Parasitology | volume = 134 | issue = Pt 9 | pages = 1215–1221 | date = August 2007 | pmid = 17428352 | doi = 10.1017/S0031182007002600 | s2cid = 22482704 }}</ref> This effect may have therapeutical relevance given that the schistosome, as the [[Taenia (flatworm)|''Taenia'']] and the ''[[Echinococcus]]'' (other praziquantel-sensitive parasites), is unable to synthesize [[purine]]s, such as adenosine, ''de novo''.{{cn|date=February 2023}}

Bayer's Animal Health Division website states, "Praziquantel is active against cestodes (tapeworms). Praziquantel is absorbed, metabolized in the liver, and excreted in the bile. Upon entering the digestive tract from the bile, cestocidal activity is exhibited. Following exposure to praziquantel, the tapeworm loses its ability to resist digestion by the mammalian host. Because of this, whole tapeworms, including the [[cestoda|scolices]] (plural of "scolex"), are very rarely passed after administration of praziquantel. In many instances, only disintegrated and partially digested pieces of tapeworms will be seen in the stool. The majority of tapeworms are digested and are not found in the feces."<ref>{{Cite web |url=http://bayer.naccvp.com/view_label.php |title=Archived copy |access-date=24 March 2010 |archive-date=18 May 2007 |archive-url=https://web.archive.org/web/20070518114008/http://bayer.naccvp.com/view_label.php }}{{full citation needed|date=March 2017}}</ref>

Praziquantel is administered as a [[Racemic mixture|racemate]], but only the (''R'')-[[enantiomer]] is biologically active; the enantiomers may be separated using a resolution of an [[amine]] obtained from praziquantel.<ref name="Todd PZQ">{{cite journal | vauthors = Woelfle M, Seerden JP, de Gooijer J, Pouwer K, Olliaro P, Todd MH | title = Resolution of praziquantel | journal = PLOS Neglected Tropical Diseases | volume = 5 | issue = 9 | article-number = e1260 | date = September 2011 | pmid = 21949890 | pmc = 3176743 | doi = 10.1371/journal.pntd.0001260 | veditors = Geary TG | doi-access = free }}</ref>

==Pharmacokinetics==
Praziquantel is well absorbed (about 80%) from the [[gastrointestinal tract]]. However, due to extensive [[First pass effect|first-pass metabolism]], only a relatively small amount enters systemic circulation. Praziquantel has a [[Blood serum|serum]] [[half-life]] of 0.8 to 1.5 hours in adults with normal renal and liver function. [[Metabolite]]s have a half-life of 4 to 5 hours. In patients with significantly impaired liver function ([[Child-Pugh score]] B and C), the serum half-life is increased to 3 to 8 hours. Praziquantel and its metabolites are mainly excreted renally; within 24 h after a single oral dose, 70 to 80% is found in urine, but less than 0.1% as the unchanged drug. Praziquantel is metabolized through the [[cytochrome P450]] pathway via [[CYP3A4]]. Agents that [[Enzyme induction and inhibition|induce or inhibit]] CYP3A4 such as [[phenytoin]], [[rifampin]], and [[Azole antifungals#Imidazole and triazole antifungals|azole]] antifungals will affect the metabolism of praziquantel.{{cn|date=February 2023}}

Praziquantel has a particularly dramatic effect on patients with [[schistosomiasis]]. Studies of those treated have shown that within six months of receiving a dose of praziquantel, up to 90% of the damage done to internal organs due to schistosomiasis infection can be reversed.<ref name="SCP"/>

==History==
Praziquantel was developed in the laboratories for parasitological research of [[Bayer AG]] and [[Merck KGaA]] in Germany (Elberfeld and Darmstadt) in the mid-1970s.{{cn|date=February 2023}}

==Society and culture==

===Brand names===
* Biltricide ([[Bayer]]) Tablets (for human use)<ref>{{Cite web|url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=34ce1cdd-648e-4f1e-8512-bf3d4cc22eb9|title=BILTRICIDE- praziquantel tablet, film coated (NDC Code(s): 50419-747-01)|website=DailyMed|date=July 2015|access-date=8 September 2015|url-status=live|archive-url=https://web.archive.org/web/20150910035308/http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=34ce1cdd-648e-4f1e-8512-bf3d4cc22eb9|archive-date=10 September 2015}}</ref>
* Cesol ([[Merck Group|Merck]]) Tablets
* Cestoved ([[Vedco]]) both tablets and injectable for veterinary use
* Cysticide (Merck) Tablets
* Distocide ([[Shin Poong Pharm]]. Co., Ltd.) tablet (for human use)
* Distoside ([[Chandra Bhagat Pharma]] Pvt Ltd) tablet (for human use)
* Droncit (Bayer) for veterinary use
* Drontal (combination with [[pyrantel pamoate]]) (Bayer) for veterinary use
* D-Worm ([[Farnum]]) for veterinary use; note that D-Worm also makes roundworm medicine containing [[piperidine]] which is not effective against tapeworms.
* Fish Tapes ([[Thomas Labs]]) for aquarium use
* Interceptor Plus chewable tablets (combination with [[milbemycin]]) ([[Elanco]]) for veterinary use. Note regular Interceptor only has milbemycin and does not contain praziquantel.
* Kaicide (Taiwan)
* Milbemax (combination with [[milbemycin oxime]]) ([[Novartis]]) for veterinary use
* Popantel ([[Jurox]])
* PraziPro ([[Hikari (company)|Hikari]]) for aquarium use
* Praz-Tastic (NFP/[[National Fish Pharmaceuticals]]) for aquarium use
* Pure Prazi ([[COTS Koi]]/Children of the Sun Koi) for aquarium use
* PraziPure (J.K.O., Inc. d/b/a Kodama Koi Farm & Kodama Koi Garden; licensed by COTS Koi) for aquarium use
* Profender (combination with [[emodepside]]) (Bayer) for veterinary use
* Tape Worm Tabs ([[Trade Winds]]) for veterinary use
* Zentozide ([[Berich]] (Thailand) Co)

===Regulatory approval===
Praziquantel is on the World Health Organization's List of Essential Medicines.<ref name="WHO23rd" />

Praziquantel is not licensed for use in humans in the UK, but it can be imported when necessary on a named-patient basis.<ref>{{Cite web| title = Antihelmintics - Medicines for Worms; threadword, roundworm| work = Patient| access-date = 15 June 2015| url = http://patient.info//health/antihelmintics-medicines-for-worms| url-status = live| archive-url = https://web.archive.org/web/20150618002318/http://patient.info/health/antihelmintics-medicines-for-worms| archive-date = 18 June 2015}}</ref> It is available in the UK as a veterinary anthelmintic.

Praziquantel is approved in the US for the treatment of schistosomiasis and liver flukes, although it is effective in other infections.<ref>{{Cite book| edition = 12| publisher = McGraw-Hill Education / Medical| isbn = 978-0-07-162442-8| vauthors = Brunton L, Chabner B, Knollman B | title = Goodman and Gilman's The Pharmacological Basis of Therapeutics, Twelfth Edition| location = New York| date = 10 January 2011}}{{page needed|date=March 2017}}</ref>

==Veterinary medicine==
* [[Salmon poisoning disease]]
* ''[[Diplozoon paradoxum]]'' and other [[Trematoda]] infections of many fish species<ref name="NIH">{{cite journal | vauthors = Schmahl G, Taraschewski H | title = Treatment of fish parasites. 2. Effects of praziquantel, niclosamide, levamisole-HCl, and metrifonate on monogenea (Gyrodactylus aculeati, Diplozoon paradoxum) | journal = Parasitology Research | volume = 73 | issue = 4 | pages = 341–351 | year = 1987 | pmid = 3615395 | doi = 10.1007/bf00531089 | s2cid = 12241452 }}</ref>

In March 2025, the [[Committee for Veterinary Medicinal Products]] of the [[European Medicines Agency]] adopted a positive opinion, recommending the granting of a marketing authorization for the veterinary medicinal product 'Prazivetin premix for medicated feeding stuff' intended for sea bream.<ref name="Prazivetin EPAR" /> The applicant for this veterinary medicinal product is Vethellas S.A.<ref name="Prazivetin EPAR" /> The main benefit of Prazivetin is its efficacy against infestations of the gills caused by the monogenean ''[[Sparicotyle chrysophrii]]''.<ref name="Prazivetin EPAR">{{cite web | title=Prazivetin EPAR | website=[[European Medicines Agency]] (EMA) | date=13 March 2025 | url=https://www.ema.europa.eu/en/medicines/veterinary/EPAR/prazivetin | access-date=19 March 2025}} Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.</ref> Praziquantel was authorized for veterinary use in the European Union in April 2025.<ref name="Prazivetin EPAR" /><ref name="Prazivetin PI">{{cite web | title=Prazivetin PI | website=Union Register of medicinal products | date=28 April 2025 | url=https://ec.europa.eu/health/documents/community-register/html/v340.htm | access-date=3 May 2025}}</ref>

== References ==
{{reflist}}

== External links ==
{{Wiktionary}}
* {{Cite web|url=http://reference.medscape.com/drug/biltricide-praziquantel-342666|title=Praziquantel (Rx) Biltricide|website=Medscape|publisher=WebMD|access-date=1 November 2015}}

{{Anthelmintics}}
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[[Category:Anthelmintics]]
[[Category:Antiparasitic agents]]
[[Category:Carboxamides]]
[[Category:Drugs developed by Bayer]]
[[Category:Drugs developed by Merck]]
[[Category:Lactams]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Veterinary drugs]]
[[Category:World Health Organization essential medicines]]
[[Category:Nitrogen heterocycles]]
[[Category:Heterocyclic compounds with 3 rings]]
[[Category:Cyclohexyl compounds]]

Praziquantel - Revision history

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