Ivermectin

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Ivermectin
Systematic (IUPAC) name
Ivermectin (22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b)
Identifiers
CAS number 70288-86-7 71827-03-7
ATC code P02CF01 QP54AA01 QS02QA03
PubChem 6474909
DrugBank APRD01058
Chemical data
Formula C48H74O14 (22,23-dihydroavermectin B1a)
C47H72O14 (22,23-dihydroavermectin B1b) 
Mol. mass 875.10 g/mol
Pharmacokinetic data
Bioavailability  ?
Protein binding 93%
Metabolism liver; CYP450
Half life 18 hours
Excretion feces; <1% urine
Therapeutic considerations
Pregnancy cat.

B3(AU) C(US)
Legal status
Routes Oral


Ivermectin (22,23-dihydroavermectin B1a + 22,23-dihydroavermectin B1b) is a broad-spectrum antiparasitic medication.

It is sold under brand names Stromectol in the United States, Mectizan in Canada by Merck and Ivexterm in Mexico by Valeant Pharmaceuticals International.

Contents

[edit] Uses

It is traditionally used against worms, but more recently found to be effective against mites[1][2][3] and some lice too.[4][5]

Ivermectin, under the brand name Mectizan, is currently being used to help eliminate river blindness (onchocerciasis) in the Americas and stop transmission of lymphatic filariasis and onchocerciasis around the world.[6] [7] [8] Currently, large amounts of Ivermectin are donated by Merck to fight river blindness in countries that are unable to afford the drug [9]. The disease is endemic in 30 African countries, 6 Latin American countries and Yemen, according to studies conducted by the World Health Organization. [10] The drug rapidly kills microfilariae but not the adult worms. A single oral dose of ivermectin, taken annually for the 10-15 year life span of the adult worms, is all that is needed to protect the individual from onchocerciasis. [11]

[edit] Veterinary use

Ivermectin is also used in veterinary medicine, particularly for horses and dogs. It is sometimes mixed with other medications to reach a wide spectrum of animal parasites. Some collie breeds (especially the Rough Collie and the Smooth Collie) are affected by a genetic defect, a mutation within the MDR1 gene. Affected dogs are very sensitive to some drugs, such as Ivermectin, as well as to some antibiotics, opioids and steroids – over 100 drugs in total.

[edit] Pharmacodynamics

Ivermectin and other avermectins (insecticides most frequently used in home-use ant baits) are macrocyclic lactones derived from the bacterium Streptomyces avermitilis. Ivermectin kills by interfering with nervous system and muscle function, in particular by enhancing inhibitory neurotransmission.

The drug binds and activates glutamate-gated chloride channels (GluCls)[12]. GluCls are invertebrate-specific members of the Cys-loop family of ligand-gated ion channels present in neurons and myocytes.

[edit] Pharmacokinetics

Ivermectin can be given either per os or parenterally. It does not readily cross the blood-brain barrier of mammals,[citation needed] although crossing may still become significant if ivermectin is given at high doses (in which case, brain levels peak 2-5 hours after administration).

[edit] Toxicity

The main concern is neurotoxicity, which in most mammalian species may manifest as CNS depression, and consequent ataxia, as might be expected from potentiation of inhibitory GABA-ergic synapses

[edit] Ecotoxicity

Field studies have demonstrated that the dung of animals treated with ivermectin supports a significantly reduced diversity of invertebrates, and that the dung persists for longer.[13]

[edit] Indications for use

[edit] Humans

Ivermectin is a broad-spectrum antiparasitic agent. It is mainly used in humans in the treatment of onchocerciasis, but is also effective against other worm infestations (such as strongyloidiasis, ascariasis, trichuriasis, filariasis and enterobiasis). More recent evidence supports its off-label use in the treatment of mites such as scabies,[3] usually limited to cases that prove resistant to topical treatments and/or who present in advanced state (such as Norwegian scabies).

[edit] References

  1. ^ Brooks PA, Grace RF (August 2002). "Ivermectin is better than benzyl benzoate for childhood scabies in developing countries". J Paediatr Child Health 38 (4): 401–4. doi:10.1046/j.1440-1754.2002.00015.x. PMID 12174005. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1034-4810&date=2002&volume=38&issue=4&spage=401. 
  2. ^ Victoria J, Trujillo R (2001). "Topical ivermectin: a new successful treatment for scabies". Pediatr Dermatol 18 (1): 63–5. doi:10.1046/j.1525-1470.2001.018001063.x. PMID 11207977. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0736-8046&date=2001&volume=18&issue=1&spage=63. 
  3. ^ a b Strong M, Johnstone PW (2007). "Interventions for treating scabies". Cochrane Database of Systematic Reviews (Online) (3): CD000320. doi:10.1002/14651858.CD000320.pub2. PMID 17636630. 
  4. ^ Dourmishev AL, Dourmishev LA, Schwartz RA (December 2005). "Ivermectin: pharmacology and application in dermatology". International Journal of Dermatology 44 (12): 981–8. doi:10.1111/j.1365-4632.2004.02253.x. PMID 16409259. 
  5. ^ Strycharz JP, Yoon KS, Clark JM (January 2008). "A new ivermectin formulation topically kills permethrin-resistant human head lice (Anoplura: Pediculidae)". Journal of Medical Entomology 45 (1): 75–81. doi:10.1603/0022-2585(2008)45[75:ANIFTK]2.0.CO;2. PMID 18283945. 
  6. ^ The Carter Center, "River Blindness (Onchocerciasis) Program", http://www.cartercenter.org/health/river_blindness/index.html, retrieved 2008-07-17 
  7. ^ The Carter Center, "Lymphatic Filariasis Elimination Program", http://www.cartercenter.org/health/lf/index.html, retrieved 2008-07-17 
  8. ^ WHO, "African Programme for Onchocerciasis Control" 
  9. ^ http://www.mectizan.org/about.asp
  10. ^ United Front Against Riverblindness, "Riverblindness", http://www.riverblindness.org/index.php?menu=tn2&page=aboutRiverblindness 
  11. ^ United Front Against Riverblindness, "Riverblindness", http://www.riverblindness.org/index.php?menu=tn3&page=Treatment 
  12. ^ Yates DM, Wolstenholme AJ (August 2004). "An ivermectin-sensitive glutamate-gated chloride channel subunit from Dirofilaria immitis". Int. J. Parasitol. 34 (9): 1075–81. doi:10.1016/j.ijpara.2004.04.010. PMID 15313134. http://linkinghub.elsevier.com/retrieve/pii/S0020751904000979. 
  13. ^ Iglesias LE, Saumell CA, Fernández AS, et al. (December 2006). "Environmental impact of ivermectin excreted by cattle treated in autumn on dung fauna and degradation of faeces on pasture". Parasitology Research 100 (1): 93–102. doi:10.1007/s00436-006-0240-x. PMID 16821034. 

[edit] See also

[edit] External links

v • d • e
Antiparasitics – Anthelmintics (P02)
Antiplatyhelmintic agents
Binds tubulin
Other/unknown
Binds tubulin
Other/unknown
Antinematodal agents
(macrofilaricides)
Binds tubulin
macrolide (Ivermectin#)
Other/unknown
#WHO-EM. ‡Withdrawn from market. CLINICAL TRIALS: †Phase III. §Never to phase III
see also diseases
v • d • e
Ectoparasiticides / arthropod (P03)
Insecticide/pediculicide
Chlorine-containing products
Ivermectin
Arachnicide/miticide/scabicide
Ivermectin
Sulfur-containing products
Chlorine-containing products
Other/ungrouped
#WHO-EM. ‡Withdrawn from market. CLINICAL TRIALS: †Phase III. §Never to phase III
See also arthropod infestations
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