Editing Suxamethonium chloride (section)

===Apnea===
{{See also|Pseudocholinesterase deficiency}}

The normal short duration of action of suxamethonium is due to the rapid metabolism of the drug by non-specific plasma cholinesterases. However, plasma cholinesterase activity is reduced in some people due to either genetic variation or acquired conditions, which results in a prolonged duration of neuromuscular block. Genetically, ninety six percent of the population have a normal (Eu:Eu) genotype and block duration; however, some people have atypical genes (Ea, Es, Ef) which can be found in varying combinations with the Eu gene, or other atypical genes (see [[Pseudocholinesterase deficiency]]). Such genes will result in a longer duration of action of the drug, ranging from 20 minutes up to several hours. Acquired factors that affect plasma cholinesterase activity include pregnancy, liver disease, kidney failure, [[heart failure]], [[thyrotoxicosis]], and cancer, as well as a number of other drugs.<ref>{{cite book | vauthors = Peck TE, Hill SA, Williams M | title = Pharmacology for Anaesthesia and Intensive Care | edition = 2nd | publisher = Greenwich Medical Media Limited | location = London, UK | date = 2003 | isbn = 1-84110-166-4 }}</ref>

If unrecognized by a clinician it could lead to awareness if anesthesia is discontinued whilst still paralyzed or hypoxemia (and potentially fatal consequences) if artificial ventilation is not maintained. Normal treatment is to maintain sedation and ventilate the patient on an intensive care unit until muscle function has returned. Blood testing for cholinesterase function can be performed.{{medical citation needed|date=January 2020}}

[[Mivacurium]], a non-depolarizing neuromuscular blocking drug, is also metabolized via the same route with a similar clinical effect in patients deficient in plasma cholinesterase activity.{{medical citation needed|date=January 2020}}

Deliberate induction of conscious apnea using this drug led to its use as a form of [[aversion therapy]] in the 1960s and 1970s in some prison and institutional settings.<ref>{{cite journal | vauthors = Reimringer MJ, Morgan SW, Bramwell PF | year = 1970 | title = Succinylcholine as a modifier of acting-out behavior | journal = Clinical Medicine | volume = 77 | issue = 7| page = 28 }}</ref><ref>{{cite news | author-link = Nicholas von Hoffman | vauthors = von Hoffman N | title = A Bit of 'Clockwork Orange,' California-Style | newspaper = Washington Post | date = 5 April 1972 | url = https://news.google.com/newspapers?nid=1755&dat=19720408&id=rLkqAAAAIBAJ&pg=7180%2C2668925 }}</ref><ref>{{cite book | vauthors = Sansweet RJ | date = 1975 | title = The Punishment Cure | location = New York | publisher = Mason/Charter | isbn = 0-88405-118-8 }}</ref> This use was discontinued after negative publicity concerning the terrifying effects on subjects of this treatment and ethical questions about the punitive use of painful aversion.{{citation needed|date=November 2014}}