Editing Saxitoxin (section)

== Illness and poisoning ==

===Toxicology===

Saxitoxin is highly toxic to [[guinea pig]]s, fatal at only 5&nbsp;μg/kg when [[Intramuscular injection|injected intramuscularly]]. The [[median lethal dose]] (LD<sub>50</sub>) for mice is very similar with varying administration routes: [[intravenous injection|i.v.]] is 3.4&nbsp;μg/kg, [[intraperitoneal injection|i.p.]] is 10&nbsp;μg/kg and [[per os|p.o.]] is 263&nbsp;μg/kg. The oral LD<sub>50</sub> for humans is 5.7&nbsp;μg/kg, therefore approximately 0.57&nbsp;mg of saxitoxin is lethal if ingested and the lethal dose by injection is about one-tenth of that (approximately 0.6&nbsp;μg/kg). The human inhalation toxicity of [[aerosol]]ized saxitoxin is estimated to be 5&nbsp;mg·min/m<sup>3</sup>. Saxitoxin can enter the body via open wounds and a lethal dose of 50&nbsp;μg/person by this route has been suggested.<ref>{{cite journal|last=Patocka J |author2=Stredav L |title=Brief Review of Natural Nonprotein Neurotoxins|journal=ASA Newsletter|date=April 23, 2002|volume=02-2|issue=89|pages=16–23|url=http://www.asanltr.com/newsletter/02-2/articles/Neurotoxins.htm|access-date=26 May 2012|editor1-first=Richard|editor1-last=Price|issn=1057-9419}}</ref>

===Illness in humans===

The human illness associated with ingestion of harmful levels of saxitoxin is known as [[paralytic shellfish poisoning]], or PSP, and saxitoxin and its derivatives are often referred to as "PSP toxins".<ref name="uhm"/>

The medical and environmental importance of saxitoxin derives from the consumption of contaminated [[shellfish]] and certain finfish which can concentrate the toxin from dinoflagellates or cyanobacteria. The blocking of neuronal [[sodium channel]]s which occurs in PSP produces a [[flaccid paralysis]] that leaves its victim calm and conscious through the progression of [[symptom]]s. Death often occurs from [[respiratory failure]]. PSP toxins have been implicated in various marine animal mortalities involving [[food chain|trophic transfer]] of the toxin from its algal source up the food chain to higher [[predator]]s.<ref name="sax"/>

Studies in animals have shown that the lethal effects of saxitoxin can be reversed with [[4-aminopyridine]],<ref>
{{Cite journal 
| last1 = Benton | first1 = B. J. | last2 = Keller | first2 = S. A. | last3 = Spriggs | first3 = D. L. | last4 = Capacio | first4 = B. R. | last5 = Chang | first5 = F. C. | title = Recovery from the lethal effects of saxitoxin: A therapeutic window for 4-aminopyridine (4-AP) | journal = Toxicon | volume = 36 | issue = 4 | pages = 571–588 | year = 1998 | pmid = 9643470 | doi=10.1016/s0041-0101(97)00158-x| bibcode = 1998Txcn...36..571B }}</ref><ref>
{{Cite journal 
| doi = 10.1006/faat.1997.2328 | last1 = Chang | first1 = F. C. | last2 = Spriggs | first2 = D. L. | last3 = Benton | first3 = B. J. | last4 = Keller | first4 = S. A. | last5 = Capacio | first5 = B. R. | title = 4-Aminopyridine reverses saxitoxin (STX)- and tetrodotoxin (TTX)-induced cardiorespiratory depression in chronically instrumented guinea pigs | journal = Fundamental and Applied Toxicology | volume = 38 | issue = 1 | pages = 75–88 | year = 1997 | pmid = 9268607| s2cid = 17185707 
}}</ref><ref>
{{Cite journal 
| last1 = Chen | first1 = H. | last2 = Lin | first2 = C. | last3 = Wang | first3 = T. | doi = 10.1006/taap.1996.0258 | title = Effects of 4-Aminopyridine on Saxitoxin Intoxication | journal = Toxicology and Applied Pharmacology | volume = 141 | issue = 1 | pages = 44–48 | year = 1996 | pmid = 8917674 
}}</ref> but there are no studies on human subjects. As with any paralytic agent, where the acute concern is respiratory failure, mouth-to-mouth resuscitation or [[artificial ventilation]] of any means will keep a poisoned victim alive until [[antidote]] is administered or the poison wears off.<ref>
{{cite web 
| url=https://fishdept.sabah.gov.my/sites/default/files/uploads/basicpage/files/458/redtideinfoeng.pdf | archive-url=https://web.archive.org/web/20211025051457/https://fishdept.sabah.gov.my/sites/default/files/uploads/basicpage/files/458/redtideinfoeng.pdf | url-status=dead | archive-date=October 25, 2021 | title=Paralytic shellfish poisoning (PSP) | access-date= April 10, 2022 | publisher= Fish Dept. Sabah Malaysia
}}</ref>