Editing Permethrin (section)

== Uses ==
=== Insecticide ===
* In agriculture, to protect crops (a drawback is that it is lethal to bees)
* In agriculture, to kill livestock parasites
* For industrial and domestic insect control
* In the textile industry, to prevent insect attack of woollen products
* In aviation, the [[WHO]], [[International Health Regulations|IHR]] and [[ICAO]] require arriving aircraft be [[Aircraft disinsection|disinsected]] prior to embarkation, departure, descent, or deplaning in certain countries. Aircraft disinsection with permethrin-based products is recommended only prior to embarkation. Prior to departure (after boarding), at the top of descent or on arrival, d-phenothrin-based (1R-trans phenothrin) aircraft insecticides are recommended.
[[File:Permethrin 0.5%.png|thumb|0.5% permethrin powder]]

=== Insect incapacitation ===
* As a personal protective measure, 0.5% permethrin is applied to outer clothing. It is a cloth impregnant, notably in mosquito nets and field wear. While permethrin may be marketed as an insect repellent, it does not prevent insects from landing. Instead it works by incapacitating or killing insects on contact before they can bite. In 2016, Consumer Reports found that, as consecutive washes reduce permethrin concentration, incapacitation becomes too slow to prevent bites. In these cases, other common topical [[Insect repellent|repellents]] such as [[icaridin]] may be applied to the clothing, though some, such as [[DEET]] and [[Ethyl butylacetylaminopropionate|IR3535]], can damage certain synthetic fabrics.<ref>{{cite web | vauthors = Jeneen I |title=Can Permethrin Treated Clothing Help You Avoid Mosquito Bites? |url=https://www.consumerreports.org/insect-repellents/permethrin-treated-clothing-mosquito-bites/ |website=Consumer Reports |date=26 May 2016 |access-date=31 May 2019 |archive-date=31 May 2019 |archive-url=https://web.archive.org/web/20190531050608/https://www.consumerreports.org/insect-repellents/permethrin-treated-clothing-mosquito-bites/ |url-status=live }}</ref><ref name="usepa"/><ref>{{cite web |title=How to Use Permethrin on Clothing, Safely |url=https://www.consumerreports.org/health/insect-repellent/how-to-use-permethrin-on-clothing-safely-a4370607226/ |publisher=Consumer Reports |access-date=29 May 2023 |archive-date=6 May 2023 |archive-url=https://web.archive.org/web/20230506205018/https://www.consumerreports.org/health/insect-repellent/how-to-use-permethrin-on-clothing-safely-a4370607226/ |url-status=live }}</ref><ref>{{cite web |title=How to Use Permethrin |date=18 March 2020 |url=https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html |publisher=U.S. [[Centers for Disease Control and Prevention]] (CDC) |access-date=11 September 2023}}</ref>
* In pet flea preventive collars or treatment (safe for use on dogs but not cats<ref>{{cite journal | vauthors = Malik R, Ward MP, Seavers A, Fawcett A, Bell E, Govendir M, Page S | title = Permethrin spot-on intoxication of cats Literature review and survey of veterinary practitioners in Australia | journal = Journal of Feline Medicine and Surgery | volume = 12 | issue = 1 | pages = 5–14 | date = January 2010 | pmid = 20123482 | doi = 10.1016/j.jfms.2009.12.002 | s2cid = 1234198 | pmc = 10845477 }}</ref>)
* In timber treatment

=== Medical use ===

Permethrin is available for topical use as a cream or lotion. It is [[indicated]] for the treatment and prevention in exposed individuals of [[head lice]] and treatment of [[scabies]].<ref>{{cite web|title=Permethrin (Lexi-Drugs)|url=http://www.lexi.com/|work=Lexicomp Online|publisher=Wolters Kluwer|access-date=19 April 2014|url-status=live|archive-url=https://web.archive.org/web/20140417164854/http://www.lexi.com/|archive-date=17 April 2014}}</ref>
In general, one treatment is curative.<ref>{{cite web|title=Permethrin Patient Package Insert|url=https://www.accessdata.fda.gov/drugsatfda_docs/anda/98/074806ap.pdf|publisher=FDA|access-date=19 April 2014|url-status=live|archive-url=https://web.archive.org/web/20140420043409/http://www.accessdata.fda.gov/drugsatfda_docs/anda/98/074806ap.pdf|archive-date=20 April 2014}}</ref> A single application of permethrin is more effective than a single oral dose of ivermectin for scabies. In addition permethrin provides more rapid symptomatic relief than ivermectin.<ref>{{cite journal | vauthors = Usha V, Gopalakrishnan Nair TV | title = A comparative study of oral ivermectin and topical permethrin cream in the treatment of scabies | journal = Journal of the American Academy of Dermatology | volume = 42 | issue = 2 Pt 1 | pages = 236–240 | date = February 2000 | pmid = 10642678 | doi = 10.1016/S0190-9622(00)90131-2 | publication-date = Feb 2000 }}</ref> When a second dose of ivermectin is days later, the efficacy between permethrin and ivermectin approach parity.<ref>{{cite journal | vauthors = Dhana A, Yen H, Okhovat JP, Cho E, Keum N, Khumalo NP | title = Ivermectin versus permethrin in the treatment of scabies: A systematic review and meta-analysis of randomized controlled trials | journal = Journal of the American Academy of Dermatology | volume = 78 | issue = 1 | pages = 194–198 | date = January 2018 | pmid = 29241784 | doi = 10.1016/j.jaad.2017.09.006 | s2cid = 29398956 | doi-access = free | publication-date = Jan 2018 }}</ref>  Contact with eyes should be avoided.<ref name="Package Label">{{cite web|title=Package Label|url=https://www.accessdata.fda.gov/drugsatfda_docs/anda/2000/75014_Permethrin_Prntlbl.pdf|publisher=Alpharma, USPD, Inc. Baltimore|access-date=19 April 2014|url-status=live|archive-url=https://web.archive.org/web/20140420031625/http://www.accessdata.fda.gov/drugsatfda_docs/anda/2000/75014_Permethrin_Prntlbl.pdf|archive-date=20 April 2014}}</ref>

==== Mechanism of action ====
Permethrin acts on the nerve cell membrane to disrupt the sodium channel current by which the polarization of the membrane is regulated. Delayed repolarization and paralysis of the pests are the consequences of this disturbance.<ref>{{cite web |title=MarkerDB |url=https://markerdb.ca/conditions/6982 |access-date=2 January 2024 |website=markerdb.ca |archive-date=2 January 2024 |archive-url=https://web.archive.org/web/20240102133744/https://markerdb.ca/conditions/6982 |url-status=live }}</ref><ref>{{cite web |title=Permethrin Cream, 5%* |url=https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=041444b6-a71e-4d13-8d24-f2d104bf721d&type=display |access-date=2 January 2024 |website=dailymed.nlm.nih.gov}}</ref>

=== Pest control / effectiveness and persistence ===
In agriculture, permethrin is mainly used on cotton, wheat, [[maize]], and alfalfa crops. Its use is controversial because, as a [[broad-spectrum]] chemical, it kills indiscriminately; as well as the intended pests, it can harm beneficial insects, including [[honey bee]]s, as well as cats and aquatic life.<ref>{{cite journal | vauthors = Ian RH | title = Aquatic organisms and pyrethroids | year = 1989 | journal = [[Pesticide Science]] | volume = 27 | issue = 4 | pages = 429–457 | doi = 10.1002/ps.2780270408}}</ref><ref>{{cite journal | vauthors = Drago B, Shah NS, Shah SH | title = Acute permethrin neurotoxicity: Variable presentations, high index of suspicion | journal = Toxicology Reports | volume = 1 | pages = 1026–1028 | date = 2014 | pmid = 28962315 | pmc = 5598406 | doi = 10.1016/j.toxrep.2014.09.007 | bibcode = 2014ToxR....1.1026D }}</ref>

Permethrin kills ticks and mosquitoes on contact with treated clothing. A method of reducing deer tick populations by treating rodent vectors involves stuffing biodegradable cardboard tubes with permethrin-treated cotton. Mice collect the cotton for lining their nests. Permethrin on the cotton kills any immature ticks feeding on the mice.{{citation needed|date=December 2022}}

Permethrin is used in tropical areas to prevent mosquito-borne disease such as [[dengue fever]] and [[malaria]]. Mosquito nets used to cover beds may be treated with a solution of permethrin. This increases the effectiveness of the bed net by killing parasitic insects before they are able to find gaps or holes in the net. Personnel working in malaria-endemic areas may be instructed to treat their clothing with permethrin as well.{{citation needed|date=February 2023}}

Permethrin is the most commonly used insecticide worldwide for the protection of wool from keratinophagous insects such as ''[[Tineola bisselliella]]''.<ref>{{cite journal | vauthors = Ingham PE, McNeil SJ, Sunderland MR | year = 2012 | title = Functional finishes for wool – Eco considerations | journal = Advanced Materials Research | volume = 441 | pages = 33–43 | doi = 10.4028/www.scientific.net/amr.441.33| s2cid = 136607213 }}</ref>

To better protect soldiers from the risk and annoyance of biting insects, the British<ref>{{cite web | url = http://www.army.mod.uk/documents/general/Black_Bag_A5_booklet.pdf | work = Personal Clothing – British Army Website | archive-url = https://web.archive.org/web/20150923185556/http://www.army.mod.uk/documents/general/Black_Bag_A5_booklet.pdf | archive-date=23 September 2015 | title = What's in the Black Bag? | access-date = 14 October 2015 }}</ref> and US armies are treating all new uniforms with permethrin.<ref>{{cite web | url = https://www.army.mil/article/88171/Army_s_new_ACUs_combat_insect_borne_diseases/ | title = Insect-repelling ACUs now available to all Soldiers | archive-url = https://web.archive.org/web/20131004213322/http://www.army.mil/article/88171/Army_s_new_ACUs_combat_insect_borne_diseases/ | archive-date = 4 October 2013| work = Canadian and United States Army | url-status = live | date = October 2012 }}</ref>

Permethrin (as well as other long-term pyrethroids) is effective over several months, in particular when used indoors. International studies report that permethrin can be detected in house dust, in fine dust, and on indoor surfaces even years after the application. Its degradation rate under indoor conditions is approximately 10% after 3 months.<ref>{{cite journal | vauthors = Nakagawa LE, do Nascimento CM, Costa AR, Polatto R, Papini S | title = Persistence of indoor permethrin and estimation of dermal and non-dietary exposure | journal = Journal of Exposure Science & Environmental Epidemiology | volume = 30 | issue = 3 | pages = 547–553 | date = May 2020 | pmid = 30926895 | doi = 10.1038/s41370-019-0132-7 | bibcode = 2020JESEE..30..547N | s2cid = 85566713 }}</ref><ref>{{cite journal | vauthors = Berger-Preiess E, Preiess A, Sielaff K, Raabe M, Ilgen B, Levsen K |doi=10.1111/j.1600-0668.1997.00004.x|title=The Behaviour of Pyrethroids Indoors: A Model Study|year=1997 |journal=Indoor Air|volume=7|issue=4|pages=248–262|bibcode=1997InAir...7..248B |doi-access=free}}</ref>

=== Resistance ===
In ''[[Aedes aegypti]]'' permethrin resistance is via "[[knockdown resistance]]" (kdr) mutations which is common to pyrethroids and [[DDT]]. This differs to the most common mechanism of [[insecticide resistance]] evolution which is [[selection (genetics)|selection]] for preexisting, low-frequency [[allele]]s. García et al. 2009 found that a kdr allele has rapidly spread throughout Mexico and become dominant there.<ref name="Labbe-et-al-2011">{{cite book | vauthors = Labbé P, Alout H, Djogbénou L, Pasteur N, Weill M | veditors = Tibayrenc M | title=Genetics and Evolution of Infectious Disease | chapter=Evolution of Resistance to Insecticide in Disease Vectors | publisher=[[Elsevier]] | year=2011 | isbn=978-0-12-384890-1 | pages=363–409}}</ref>