{{Short description|Topical antiseptic and supplement}} {{Use dmy dates|date=December 2019}} {{cs1 config|name-list-style=vanc|display-authors=6}} {{For-text|the element|Iodine|"Iodine" (capsule, iodized oil)|Lipiodol,<ref name=WHO2008>{{cite book | title = WHO Model Formulary 2008 | year = 2009 | isbn = 978-92-4-154765-9 | veditors = Stuart MC, Kouimtzi M, Hill SR | hdl = 10665/44053 | publisher = World Health Organization | page=499 | hdl-access=free }}</ref> as found in the WHO Model List of Essential Medicines}}<!-- Definition and medical uses -->

'''Iodine''' is a chemical element with many uses in medicine, depending on the form. Elemental iodine and iodophors are topical antiseptics.<ref name="AHFS2017">{{cite web|title=Iodine|url=https://www.drugs.com/monograph/iodine.html|publisher=The American Society of Health-System Pharmacists|access-date=8 January 2017|url-status=live|archive-url=https://web.archive.org/web/20170113090731/https://www.drugs.com/monograph/iodine.html|archive-date=13 January 2017}} &ndash; This article deals with iodine for topical use. The listed brand names (Iodoflex, Iodosorb) are more appropriately attributed to cadexomer iodine, ATC code D03AX01.</ref> Iodine, in non-elemental form, functions as an essential nutrient in human biology (see iodine in biology).<ref>{{Cite web |title=Iodine Deficiency |url=https://www.thyroid.org/iodine-deficiency/ |access-date=2022-11-18 |website=American Thyroid Association |language=en-US |archive-date=18 November 2022 |archive-url=https://web.archive.org/web/20221118193754/https://www.thyroid.org/iodine-deficiency/ }}</ref> Organic compounds containing iodine are also useful iodinated contrast agents in X-ray imaging.<ref name="CONTRAST" />

<!-- Side effects and mechanism: should possibly be split --> Common side effects when applied to the skin include irritation and discoloration.<ref name=AHFS2017/> Supplementation during pregnancy is recommended in regions where deficiency is common, otherwise it is not recommended.<ref name=WHO2008/> Iodine is an essential trace element.<ref name=WHO2008/>

<!-- History and culture --> In 1811, Bernard Courtois isolated iodine from seaweed, and then in 1820 Jean-Francois Coindet linked iodine intake to goiter size.<ref name=Leung>{{cite journal | vauthors = Leung AM, Braverman LE, Pearce EN | title = History of U.S. iodine fortification and supplementation | journal = Nutrients | volume = 4 | issue = 11 | pages = 1740–1746 | date = November 2012 | pmid = 23201844 | pmc = 3509517 | doi = 10.3390/nu4111740 | doi-access = free }}</ref> It initially came into use as a disinfectant and a treatment for goiter.<ref>{{cite book| vauthors = Starke JA | chapter = 14. Application of Iodine Water Purification Tablets: Iodine's Efficacy against Cryptosporidium parvum. | veditors = Preedy VR, Burrow GN, Watson RR | title=Comprehensive Handbook of Iodine: Nutritional, Biochemical, Pathological and Therapeutic Aspects|date=2009|publisher=Academic Press|isbn=978-0-08-092086-3|page=135| chapter-url=https://books.google.com/books?id=7v7g5XoCQQwC&pg=PA135|language=en|url-status=live|archive-url=https://web.archive.org/web/20170812100039/https://books.google.ca/books?id=7v7g5XoCQQwC&pg=PA135|archive-date=2017-08-12}}</ref><ref>{{cite book| vauthors = Sneader W | chapter = Legacy of the Past |title=Drug Discovery: A History|date=2005|publisher=John Wiley & Sons|isbn=978-0-471-89979-2| chapter-url= https://books.google.com/books?id=Cb6BOkj9fK4C&pg=PA66|language=en|url-status=live |archive-url= https://web.archive.org/web/20170113125622/https://books.google.ca/books?id=Cb6BOkj9fK4C&pg=PA66 |archive-date=2017-01-13}}</ref> The following forms of iodine are found on the World Health Organization's List of Essential Medicines:<ref name="WHO21st">{{cite book | title = World Health Organization model list of essential medicines: 21st list 2019 | year = 2019 | hdl = 10665/325771 | publisher = World Health Organization | location = Geneva | id = WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO | hdl-access=free }}</ref>

* Potassium iodide<ref name="WHO21st"/>{{rp|18,42,43}} * Amidotrizoate<ref name="WHO21st"/>{{rp|40}} * Iohexol<ref name="WHO21st"/>{{rp|40}} * Meglumine iotroxat<ref name="WHO21st"/>{{rp|41}} * Povidone iodine<ref name="WHO21st"/>{{rp|41}} * "Iodine"<ref name="WHO21st"/>{{rp|50}} &ndash; less ambiguously known as iodized oil

In addition, table salt with non-elemental iodine, known as iodized salt, is available in more than 110 countries.<ref>{{cite book| vauthors = Wesley AS, Horton S | chapter = Economics of Food Fortification | veditors = Watson RR, Gerald JK, Preedy VR |title=Nutrients, Dietary Supplements, and Nutriceuticals: Cost Analysis Versus Clinical Benefits|date=2010|publisher=Springer Science & Business Media|isbn=978-1-60761-308-4|page=37|chapter-url=https://books.google.com/books?id=s-Vf9TGG91YC&pg=PA37|url-status=live|archive-url=https://web.archive.org/web/20170113125249/https://books.google.ca/books?id=s-Vf9TGG91YC&pg=PA37|archive-date=2017-01-13}}</ref>

==Forms and formulations== ===Elemental iodine=== {{Infobox drug | drug_name = Iodine, elemental | image = ExAntiseptic.jpg | alt = | caption =

<!-- Clinical data --> | synonyms = | pronounce = | tradename = | Drugs.com = {{Drugs.com|monograph|iodine}} | MedlinePlus = | DailyMedID = Iodine | pregnancy_AU = <!-- A/B1/B2/B3/C/D/X --> | pregnancy_AU_comment = | pregnancy_category= | routes_of_administration = topical

| legal_AU = <!-- S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled--> | legal_AU_comment = | legal_CA = Rx-only | legal_CA_comment = <ref>{{cite web | title=Diagnostic agents | website=Health Canada | date=8 May 2018 | url=https://www.canada.ca/en/services/health/drug-health-products/drug-medical-device-highlights-2017/approved-drugs/diagnostic-agents.html | access-date=13 April 2024}}</ref> | legal_DE = <!-- Anlage I, II, III --> | legal_NZ = <!-- Class A, B, C --> | legal_UK = <!-- GSL, P, POM, CD, CD Lic, CD POM, CD No Reg POM, CD (Benz) POM, CD (Anab) POM or CD Inv POM / Class A, B, C --> | legal_US = <!-- OTC/Rx-only/Schedule I, II, III, IV, V --> | legal_UN = <!-- N I, II, III, IV / P I, II, III, IV--> | legal_status = <!-- Free text -->

<!-- Pharmacokinetic data --> | bioavailability = | protein_bound = | metabolism = | metabolites = | onset = | elimination_half-life = | duration_of_action = | excretion =

<!-- Identifiers --> | CAS_number = 7553-56-2 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 9679TC07X4 | class = | ATCvet = | ATC_prefix = D08 | ATC_suffix = AG03 | PubChem = 807 | DrugBank = DB05382 | ChemSpiderID = 785 | ChEBI = 17606 | ChEMBL = 1201225 | KEGG = D00108

<!-- Chemical and physical data --> | chemical_formula = I<sub>2</sub> | molecular_weight = }} Elemental iodine is used as an antiseptic either as the element, or as the water-soluble triiodide anion I<sub>3</sub><sup>−</sup> generated ''in situ'' by adding iodide to poorly water-soluble elemental iodine (the reverse chemical reaction makes some free elemental iodine available for antisepsis).<ref name="WHO2008"/>

In the alternative, iodine may be produced from iodophors, which contain iodine complexed with a solubilizing agent (the iodide ion may be thought of loosely as the iodophor in triiodide water solutions). Examples of such preparations include:<ref>{{cite book | vauthors = Block SS |title=Disinfection, sterilization, and preservation |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |date=2001 |page=159 |isbn=978-0-683-30740-5}}</ref>

* Tincture of iodine: iodine in ethanol, or iodine and sodium iodide in a mixture of ethanol and water. * Lugol's iodine: iodine and iodide in water alone, forming mostly triiodide. Unlike tincture of iodine, Lugol's iodine has a minimised amount of the free iodine (I<sub>2</sub>) component. * Iodine glycerin, a preparation used in dentistry. * Povidone iodine (an iodophor). * Iodine-V: iodine (I<sub>2</sub>) and fulvic acid form a clathrate compound (iodine molecules are "caged" by fulvic acid in this host-guest complex). A water-soluble, solid, stable, crystalline complex. Unlike other iodophors, Iodine-V only contains iodine in molecular (I<sub>2</sub>) form.<ref>{{cite journal | vauthors = Köntös Z | title = Efficacy of "Essential Iodine Drops" against Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) | journal = PLOS ONE | volume = 16 | issue = 7 | article-number = e0254341 | date = 2021-07-09 | pmid = 34242340 | pmc = 8270147 | doi = 10.1371/journal.pone.0254341 | bibcode = 2021PLoSO..1654341K | doi-access = free }}</ref>

The antimicrobial action of iodine is quick and works at low concentrations, and thus it is used in operating theatres.<ref>{{cite journal | vauthors = Patwardhan N, Kelkar U | title = Disinfection, sterilization and operation theater guidelines for dermatosurgical practitioners in India | journal = Indian Journal of Dermatology, Venereology and Leprology | volume = 77 | issue = 1 | pages = 83–93 | date = 2011 | pmid = 21220895 | doi = 10.4103/0378-6323.74965 | doi-access = free }}</ref> Its specific mode of action is unknown. It penetrates into microorganisms and attacks particular amino acids (such as cysteine and methionine), nucleotides, and fatty acids, ultimately resulting in cell death. It also has an antiviral action, but nonlipid viruses and parvoviruses are less sensitive than lipid enveloped viruses. Iodine probably attacks surface proteins of enveloped viruses, and it may also destabilise membrane fatty acids by reacting with unsaturated carbon bonds.<ref name="pmid9880479">{{cite journal | vauthors = McDonnell G, Russell AD | title = Antiseptics and disinfectants: activity, action, and resistance | journal = Clinical Microbiology Reviews | volume = 12 | issue = 1 | pages = 147–179 | date = January 1999 | pmid = 9880479 | pmc = 88911 | doi = 10.1128/CMR.12.1.147 | bibcode = 1999CliMR..12..147M }}</ref>

===Iodine-containing salts=== As a nutrient, iodine enters cells as the iodide ion;<ref name="EskinGrotkowski1995">{{cite journal | vauthors = Eskin BA, Grotkowski CE, Connolly CP, Ghent WR | title = Different tissue responses for iodine and iodide in rat thyroid and mammary glands | journal = Biological Trace Element Research | volume = 49 | issue = 1 | pages = 9–19 | date = July 1995 | pmid = 7577324 | doi = 10.1007/BF02788999 | bibcode = 1995BTER...49....9E | s2cid = 24230708 }}</ref> iodide is also the form of iodine found in food such as kelp.<ref>{{cite journal | vauthors = Nagataki S, Shizume K, Nakao K | title = Thyroid function in chronic excess iodide ingestion: comparison of thyroidal absolute iodine uptake and degradation of thyroxine in euthyroid Japanese subjects | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 27 | issue = 5 | pages = 638–647 | date = May 1967 | pmid = 4164900 | doi = 10.1210/jcem-27-5-638 }}</ref>

The form of iodide salt most commonly used medically is potassium iodide. At low doses, it is one of the options for making iodized salt, along with the more stable potassium iodate. A saturated solution of potassium iodide is used to treat acute thyrotoxicosis. It is also used to block uptake of iodine-131 in the thyroid gland (see isotopes section above), when this isotope is used as part of radiopharmaceuticals (such as iobenguane) that are not targeted to the thyroid or thyroid-type tissues.<ref>{{cite web|url=http://hazard.com/msds/mf/baker/baker/files/p5906.htm |title=Solubility of KI in water |publisher=Hazard.com |date=1998-04-21 |access-date=2013-01-21}}</ref><ref>{{cite web|url=http://www.eanm.org/scientific_info/guidelines/gl_radio_ther_benzyl.pdf|archive-url=https://web.archive.org/web/20090617073253/http://www.eanm.org/scientific_info/guidelines/gl_radio_ther_benzyl.pdf | title=EANM procedure guidelines for 131I-meta-iodobenzylguanidine (131I-mIBG) therapy|archive-date=17 June 2009|date=17 June 2009}}</ref>

Iodine-131 (usually as iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine and retain it for periods longer than this isotope's radiological half-life of eight days. For this reason, people at risk of exposure to environmental radioactive iodine (iodine-131) in fallout may be instructed to take non-radioactive potassium iodide tablets. The typical adult dose is one 130&nbsp;mg tablet per 24 hours, supplying 100&nbsp;mg (100,000 micrograms) of ionic iodine (the typical daily dose of iodine for normal health is on the order of 100 micrograms). Ingestion of this large dose of non-radioactive iodine minimises the uptake of radioactive iodine by the thyroid gland.<ref>[https://www.cdc.gov/radiation-emergencies/treatment/potassium-iodide.html "Potassium Iodide (KI) | Radiation Emergencies | CDC"], U.S. Centers for Disease Control, 11 October 2006, accessed 14 November 2010.</ref>

Before the advent of organic chelating agents, salts of iodide were given orally in the treatment of lead or mercury poisoning, such as heavily popularized by Louis Melsens and many nineteenth and early twentieth century doctors.<ref>[https://books.google.com/books?id=Cj9FAAAAcAAJ&pg=PP1 "Sur l'emploi de l'iodure de potassium pour combattre les affections saturnines et mercurielles"], in ''Annales de chimie et de physique'', t. 26, 3<sup>e</sup> série, 1849.</ref><ref name=KI_en>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192934/ "On the Employment of Iodide of Potassium as a Remedy for the Affections Caused by Lead and Mercury"], in ''Br Foreign Med Chir Rev.'' 1853 Jan; 11(21): 201–224.</ref>

=== Organoiodine compounds === [[File:Diatrizoic acid.svg|class=skin-invert-image|thumb|right|Diatrizoic acid, an iodine-containing radiocontrast agent]] As an element with high electron density and atomic number, iodine absorbs X-rays weaker than 33.3&nbsp;keV due to the photoelectric effect of the innermost electrons.<ref name=CONTRAST>{{cite book | vauthors = Lancaster JL | chapter-url = http://ric.uthscsa.edu/personalpages/lancaster/DI-II_Chapters/DI_chap4.pdf | chapter = Chapter 4: Physical Determinants of Contrast | archive-url =https://web.archive.org/web/20151010172937/http://ric.uthscsa.edu/personalpages/lancaster/DI-II_Chapters/DI_chap4.pdf | archive-date=10 October 2015 | title = Physics of Medical X-Ray Imaging | publisher = The University of Texas Health Science Center }}</ref> Organoiodine compounds are used with intravenous injection as X-ray radiocontrast agents. This application is often in conjunction with advanced X-ray techniques such as angiography and CT scanning. At present, all water-soluble radiocontrast agents rely on iodine-containing compounds.

*Iohexol (contrast agent) *Amidotrizoate (contrast agent) *Meglumine iotroxate (contrast agent) *Iopanoic acid (contrast agent)

''Iodized oil'', made by reacting ether esters of fatty acids form vegetable oil with hydroiodic acid, is another important organoiodine preparation. As an iodine supplement, it is given by mouth once per year to prevent endemic goiter in remote communities.<ref name=WHO2008/><ref name=Ingenbleek>{{cite journal | vauthors = Ingenbleek Y, Jung L, Férard G, Bordet F, Goncalves AM, Dechoux L | title = Iodised rapeseed oil for eradication of severe endemic goitre | journal = Lancet | volume = 350 | issue = 9090 | pages = 1542–1545 | date = November 1997 | pmid = 9388412 | doi = 10.1016/s0140-6736(97)02427-6 }}</ref> It is also used as a non-water-soluble radiocontrast.<ref>{{cite journal | vauthors = Olliff J, Riley P |title=Radiological contrast agents and radiopharmaceuticals |journal=Side Effects of Drugs Annual |date=2012 |volume=34 |pages=749–760 |doi=10.1016/b978-0-444-59499-0.00046-5|isbn=978-0-444-59499-0 }}</ref>

Other organoiodine drugs include:

* Amiodarone, an antiarrhythmic drug. * {{ill|Iodinated glycerol|es|Glicerol yodado|it|Iodoglicerolo}}, historically used as a mucolytic.<ref>{{cite journal | vauthors = Petty TL | title = The National Mucolytic Study. Results of a randomized, double-blind, placebo-controlled study of iodinated glycerol in chronic obstructive bronchitis | journal = Chest | volume = 97 | issue = 1 | pages = 75–83 | date = January 1990 | pmid = 2403903 | doi = 10.1378/chest.97.1.75 }}</ref>

== See also == * Isotopes of iodine &ndash; lists isotopes with medical uses

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== References == {{notelist}} {{reflist}}

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Category:World Health Organization essential medicines Category:Wikipedia medicine articles ready to translate Category:Iodine