Difference between revisions of "Ivermectin"

Revision as of 14:05, 6 July 2010

Ivermectin (22,23-dihydroavermectin B_1a + 22,23-dihydroavermectin B_1b) 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.

Uses

Ivermectin is a broad-spectrum antiparasitic agent.

Helminth

It is traditionally used against worms.

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).

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.^[1][2][3] Currently, large amounts of Ivermectin are donated by Merck to fight river blindness in countries that are unable to afford the drug ^[4]. The disease is endemic in 30 African countries, 6 Latin American countries and Yemen, according to studies conducted by the World Health Organization.^[5] 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.^[6]

Arthropod

More recent evidence supports its off-label use against arthropods:

• mites such as scabies^[7][8][9]. It is usually limited to cases that prove resistant to topical treatments and/or who present in advanced state (such as Norwegian scabies).^[9]

• lice^[10][11]

Veterinary use

Ivermectin is also used in veterinary medicine, particularly for horses, dogs and cats. It is sometimes mixed with other medications to reach a wide spectrum of animal parasites. Some breeds (especially the Rough Collie, the Smooth Collie and the Australian Shepherd) 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. Kittens are also very sensitive and ivermectin should never be used on kittens less than 10-12 weeks of age. Nor should it be used on any weak, dehydrated or debilitated animal except in dire situations.^{[citation needed]}

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.

Pharmacokinetics

Ivermectin can be given either by mouth or injection. 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).

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. Dogs with defects in the P-glycoprotein gene can be severely poisoned by ivermectin.

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]

See also

• Onchocerciasis
• The Carter Center
• Lymphatic filariasis
• Neglected diseases
• United Front Against Riverblindness

References

External links

• Stromectol
• The Carter Center River Blindness (Onchocerciasis) Control Program
• Mectizan Donation Program
• American NGDO Treating River Blindness

de:Ivermectin es:Ivermectina fr:Ivermectine nl:Ivermectine ja:イベルメクチン pt:Ivermectina zh:伊維菌素

1. ↑ The Carter Center, "River Blindness (Onchocerciasis) Program", retrieved 2008-07-17 
2. ↑ The Carter Center, "Lymphatic Filariasis Elimination Program", retrieved 2008-07-17 
3. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
4. ↑ http://www.mectizan.org/about.asp
5. ↑ United Front Against Riverblindness, "Riverblindness" 
6. ↑ United Front Against Riverblindness, "Riverblindness" 
7. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
8. ↑ 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. 
9. ↑ ^{9.0 9.1} 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. 
10. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
11. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
12. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
13. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.