Praziquantel

Praziquantel
Clinical data
Pronunciation praz-i-KWAN-tel
Trade names Biltricide
AHFS/Drugs.com Monograph
MedlinePlus a608048
Pregnancy
category
  • AU: B1
  • US: B (No risk in non-human studies)
Routes of
administration
Human use: by mouth (tablets)
ATC code P02BA01 (WHO) QP52AA01 (WHO)
Legal status
Legal status
  • US: ℞-only (human use),
    OTC (veterinary use)[1]
Pharmacokinetic data
Bioavailability Relatively small
Metabolism Liver
Biological half-life 0.8–1.5 hours (main metabolites: 4–5 hours)
Excretion Urine (mainly)
Identifiers
CAS Number 55268-74-1 YesY
PubChem (CID) 4891
DrugBank DB01058 YesY
ChemSpider 4722 YesY
UNII 6490C9U457 YesY
KEGG D00471 YesY
ChEMBL CHEMBL976 YesY
Chemical and physical data
Formula C19H24N2O2
Molar mass 312.411
3D model (Jmol) Interactive image
Melting point 136 to 138 °C (277 to 280 °F)
  (verify)

Praziquantel, marketed as Biltricide, is an anthelmintic used for the treatment of tapeworms and flukes. For example, it is effective against Schistosoma (blood flukes), the liver fluke Clonorchis sinensis and the fish tapeworm Diphyllobothrium latum.

It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[2]

Medical uses

Praziquantel is used to treat diseases caused by infection with several types of internal/gastrointestinal, and external parasites, including:

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.

Pregnancy

Animal studies have failed to reveal evidence of fetal harm. There are no controlled data in human pregnancy. Praziquantel should be used during pregnancy only if clearly needed; caution is recommended.

Drug interactions

The antibiotic rifampicin decreases plasma concentrations of praziquantel.[10]

Carbamazepine and phenytoin are reported to reduce the bioavailability of praziquantel.[11]

Chloroquine reduces the bioavailability of praziquantel.[12]

The drug cimetidine heightens praziquantel bioavailability.[13][14]

Mechanism of action

The 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, 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.

Another hypothesis concerning the mechanism of action of praziquantel has been recently reported. The drug seems to interfere with adenosine uptake in cultured worms. This effect may have therapeutical relevance given that the schistosome, as the Taenia and the Echinococcus (other praziquantel-sensitive parasites), is unable to synthesize purines such as adenosine de novo.

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 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."[15]

Praziquantel is administered as a racemate, but only the (R)-enantiomer is biologically active; the enantiomers may be separated using a resolution of an amine obtained from praziquantel.[16]

Pharmacokinetics

Praziquantel is well absorbed (about 80%) from the gastrointestinal tract. However, due to extensive first-pass metabolism, only a relatively small amount enters systemic circulation. Praziquantel has a serum half-life of 0.8 to 1.5 hours in adults with normal renal and liver function. Metabolites 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 induce or inhibit CYP3A4 such as phenytoin, rifampin, and azole antifungals will affect the metabolism of praziquantel.

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.[7]

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.

Society and culture

Brand names

Regulatory approval

Praziquantel is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[2]

Praziquantel is not licensed for use in humans in the UK but it can be imported when necessary on a named patient basis.[18] It is available in the UK as a veterinary anthelmintic.

Praziquantel is FDA approved in the US for the treatment of schistosomiasis and liver fluke, although it is effective in other infections.[19]

Veterinary medicine

It may cause problems in dogs with MDR1 mutations.[21]

References

  1. "Farnam Pet Press Release. TRUSTED D-WORM™ offers product for tapeworm management". Farnam Companies, Inc. Retrieved 3 October 2016.
  2. 1 2 "WHO Model List of EssentialMedicines" (PDF). World Health Organization. October 2013. Retrieved 22 April 2014.
  3. Matthaiou DK, Panos G, Adamidi ES, Falagas ME (2008). Carabin, Hélène, ed. "Albendazole versus Praziquantel in the Treatment of Neurocysticercosis: A Meta-analysis of Comparative Trials". PLoS Negl Trop Dis. 2 (3): e194. doi:10.1371/journal.pntd.0000194. PMC 2265431Freely accessible. PMID 18335068.
  4. 1 2 3 Drontal Data Sheet; Drontal Cat & Cat XL Film-coated Tablets, Bayer plc (PDF), Newbury, England: Bayer plc, Animal Health Division, p. 2, retrieved 23 September 2015
  5. 1 2 Bowman, Dwight D.; Hendrix, Charles M.; Lindsay, David S.; Barr, Steven C. (2002). Feline clinical parasitology (First ed.). Ames, Iowa: Iowa State University. p. 275. ISBN 0-8138-0333-0.
  6. Tchuenté LA, Shaw DJ, Polla L, Cioli D, Vercruysse J (December 2004). "Efficacy of praziquantel against Schistosoma haematobium infection in children". Am. J. Trop. Med. Hyg. 71 (6): 778–82. PMID 15642971.
  7. 1 2 The Carter Center. "Schistosomiasis Control Program". Retrieved 2008-07-17.
  8. Shen C, Kim J, Lee JK, et al. (June 2007). "Collection of Clonorchis sinensis adult worms from infected humans after praziquantel treatment". The Korean Journal of Parasitology. 45 (2): 149–52. doi:10.3347/kjp.2007.45.2.149. PMC 2526309Freely accessible. PMID 17570980.
  9. Mas-Coma S, Bargues MD, Valero MA (October 2005). "Fascioliasis and other plant-borne trematode zoonoses". Int. J. Parasitol. 35 (11-12): 1255–78. doi:10.1016/j.ijpara.2005.07.010. PMID 16150452.
  10. Ridtitid W, Wongnawa M, Mahatthanatrakul W, Punyo J, Sunbhanich M (November 2002). "Rifampin markedly decreases plasma concentrations of praziquantel in healthy volunteers". Clin. Pharmacol. Ther. 72 (5): 505–13. doi:10.1067/mcp.2002.129319. PMID 12426514.
  11. Quinn DI, Day RO (June 1995). "Drug interactions of clinical importance. An updated guide". Drug Saf. 12 (6): 393–452. doi:10.2165/00002018-199512060-00005. PMID 8527014.
  12. Masimirembwa CM, Naik YS, Hasler JA (January 1994). "The effect of chloroquine on the pharmacokinetics and metabolism of praziquantel in rats and in humans". Biopharm Drug Dispos. 15 (1): 33–43. doi:10.1002/bdd.2510150103. PMID 8161714.
  13. Metwally A, Bennett JL, Botros S, Ebeid F (April 1995). "Effect of cimetidine, bicarbonate and glucose on the bioavailability of different formulations of praziquantel". Arzneimittelforschung. 45 (4): 516–8. PMID 7779153.
  14. Jung H, Medina R, Castro N, Corona T, Sotelo J (June 1997). "Pharmacokinetic study of praziquantel administered alone and in combination with cimetidine in a single-day therapeutic regimen". Antimicrob. Agents Chemother. 41 (6): 1256–9. PMC 163896Freely accessible. PMID 9174180.
  15. http://bayer.naccvp.com/view_label.php
  16. Woelfle, M.; Seerden, J. P.; De Gooijer, J.; Pouwer, K.; Olliaro, P.; Todd, M. H. (2011). Geary, Timothy G, ed. "Resolution of Praziquantel". PLoS Neglected Tropical Diseases. 5 (9): e1260. doi:10.1371/journal.pntd.0001260. PMC 3176743Freely accessible. PMID 21949890.
  17. "BILTRICIDE- praziquantel tablet, film coated (NDC Code(s): 50419-747-01)". DailyMed. July 2015. Retrieved 2015-09-08.
  18. "Antihelmintics - Medicines for Worms; threadword, roundworm". Patient. Retrieved 2015-06-15.
  19. Brunton, Laurence; Chabner, Bruce; Knollman, Bjorn (2011-01-10). Goodman and Gilman's The Pharmacological Basis of Therapeutics, Twelfth Edition (12 ed.). New York: McGraw-Hill Education / Medical. ISBN 9780071624428.
  20. "Treatment of fish parasites. 2. Effects of praziquantel, niclosamide, levamisole-HCl, and metrifonate on monogenea (Gyrodactylus aculeati, Diplozoon paradoxum)".
  21. http://www.collieassociation.co.uk/health/MDR1leaflet.pdf

External links

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