Editing Ketamine (section)

==== Relationships between levels and effects ====
[[Dissociative|Dissociation]] and [[psychotomimetic]] effects are reported in people treated with ketamine at plasma concentrations of approximately 100 to 250&nbsp;ng/mL (0.42–1.1&nbsp;μM).<ref name="pmid29945898" /> The typical intravenous antidepressant dosage of ketamine used to treat depression is low and results in maximal plasma concentrations of 70 to 200&nbsp;ng/mL (0.29–0.84&nbsp;μM).<ref name="pmid28249076" /> At similar plasma concentrations (70 to 160&nbsp;ng/mL; 0.29–0.67&nbsp;μM) it also shows analgesic effects.<ref name="pmid28249076" /> In 1–5 minutes after inducing anesthesia by rapid intravenous injection of ketamine, its plasma concentration reaches as high as 60–110&nbsp;μM.<ref name="pmid526385">{{cite journal |vauthors=Idvall J, Ahlgren I, Aronsen KR, Stenberg P |title=Ketamine infusions: pharmacokinetics and clinical effects |journal=Br J Anaesth |volume=51 |issue=12 |pages=1167–73 |date=December 1979 |pmid=526385 |doi=10.1093/bja/51.12.1167 | doi-access = free | title-link = doi }}</ref><ref name="pmid7198883">{{cite journal |vauthors=Domino EF, Zsigmond EK, Domino LE, Domino KE, Kothary SP, Domino SE |title=Plasma levels of ketamine and two of its metabolites in surgical patients using a gas chromatographic mass fragmentographic assay |journal=Anesth Analg |volume=61 |issue=2 |pages=87–92 |date=February 1982 |doi=10.1213/00000539-198202000-00004 |pmid=7198883 |s2cid=27596215 | doi-access = free | title-link = doi }}</ref> When the anesthesia was maintained using [[nitrous oxide]] together with continuous injection of ketamine, the ketamine concentration stabilized at approximately 9.3 μM.<ref name="pmid526385" /> In an experiment with purely ketamine anesthesia, people began to awaken once the plasma level of ketamine decreased to about 2,600&nbsp;ng/mL (11&nbsp;μM) and became oriented in place and time when the level was down to 1,000&nbsp;ng/mL (4&nbsp;μM).<ref name="pmid3970799">{{cite journal |vauthors=White PF, Schüttler J, Shafer A, Stanski DR, Horai Y, Trevor AJ |title=Comparative pharmacology of the ketamine isomers. Studies in volunteers |journal=Br J Anaesth |volume=57 |issue=2 |pages=197–203 |date=February 1985 |pmid=3970799 |doi=10.1093/bja/57.2.197 | doi-access = free | title-link = doi }}</ref> In a single-case study, the concentration of ketamine in [[cerebrospinal fluid]], a proxy for the brain concentration, during anesthesia varied between 2.8 and 6.5&nbsp;μM and was approximately 40% lower than in plasma.<ref name="pmid7248132">{{cite journal |vauthors=Stenberg P, Idvall J |title=Does ketamine metabolite II exist in vivo? |journal=Br J Anaesth |volume=53 |issue=7 |page=778 |date=July 1981 |pmid=7248132 |doi=10.1093/bja/53.7.778 | doi-access = free | title-link = doi }}</ref>