View source for Biology:Potassium iodide

{{Short description|Ionic compound (KI)}}
{{Infobox drug
| drug_name          = 
| type               = <!-- empty -->
| IUPAC_name         = Potassium iodide
| image              = Potassium iodide.jpg
| width              = 
| alt                = 
| caption            = 

<!-- Clinical data -->
| image2             = Potassium-iodide-3D-ionic.png
| width2             = 
| alt2               = 
| pronounce          = 
| tradename          = Iosat, Thyrosafe, Thyroshield, others
| Drugs.com          = {{Drugs.com|monograph|potassium-iodide}}
| MedlinePlus        = 
| licence_EU         = <!-- EMA requires brand name -->
| licence_US         = <!-- FDA may use generic name -->
| DailyMedID         = Potassium iodide
| pregnancy_AU       = <!-- A/B1/B2/B3/C/D/X -->
| pregnancy_AU_comment = 
| pregnancy_category = 
| routes_of_administration = By mouth
| ATCvet             = 
| ATC_prefix         = R05
| ATC_suffix         = CA02
| ATC_supplemental   = {{ATC|S01|XA04}}, {{ATC|V03|AB21}}

| legal_AU           = <!-- S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled-->
| legal_AU_comment   = 
| legal_CA           = <!-- OTC, Rx-only, Schedule I, II, III, IV, V, VI, VII, VIII -->
| legal_CA_comment   = 
| legal_DE           = <!-- Anlage I, II, III or Unscheduled-->
| legal_DE_comment   = 
| legal_NZ           = <!-- Class A, B, C -->
| legal_NZ_comment   = 
| 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_UK_comment   = 
| legal_US           = OTC
| legal_UN           = <!-- N I, II, III, IV / P I, II, III, IV-->
| legal_US_comment   = 
| legal_UN_comment   = 
| legal_status       = <!--For countries not listed above-->

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

<!-- Identifiers -->
| CAS_number         = 7681-11-0
| CAS_supplemental   = {{cascite|correct|CAS}}
| PubChem            = 4875
| PubChemSubstance   = 
| IUPHAR_ligand      = 
| DrugBank           = DB06715
| ChemSpiderID       = 4709
| UNII               = 1C4QK22F9J
| KEGG               = D01016
| ChEBI              = 8346
| ChEMBL             = 1141
| NIAID_ChemDB       = 
| synonyms           = SSKI

<!-- Chemical and physical data -->
| chemical_formula   = KI
| charge             = 
| SMILES             = [K+].[I-]
| StdInChI           = 1S/HI.K/h1H;/q;+1/p-1
| StdInChI_Ref       = {{stdinchicite|correct|chemspider}}
| StdInChIKey        = NLKNQRATVPKPDG-UHFFFAOYSA-M
| density            = 3.13<ref>{{cite web | title = Density of Potassium iodide | url = https://www.aqua-calc.com/page/density-table/substance/potassium-blank-iodide | work = Aqua-Calc }}</ref>
| density_notes      = 
| melting_point      = 681
| melting_high       = 
| melting_notes      = 
| boiling_point      = 1330
| boiling_notes      = 
| solubility         = 1280&nbsp;mg/mL  ({{Convert|0|C|F}}) <br /> 1400&nbsp;mg/mL ({{Convert|20|C|F}}) <br /> 1760&nbsp;mg/mL ({{Convert|60|C|F}}) <br /> 2060
| specific_rotation  = 
| INN                = 
| class              = 
| sol_units          = &nbsp;mg/mL ({{Convert|100|C|F}})
{{NFPA 704 diamond
 | F          = 0
 | H          = 2
 | R          = 0
 | S          = 
 | ref        =<ref>{{cite web |title=Potassium Iodide |url=http://www.labchem.com/tools/msds/msds/LC19690.pdf |access-date=10 May 2019}}</ref>
 | showimage  =
 | background = #ff7623
}}
}}

<!-- Definition and medical uses -->
'''Potassium iodide''' is a [[Chemistry:Chemical compound|chemical compound]], medication, and dietary supplement.<ref>{{cite book| author1 = National Research Council, Division on Earth and Life Studies | author2 = Board on Radiation Effects Research | author3 = Committee to Assess the Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident |title=Distribution and Administration of Potassium Iodide in the Event of a Nuclear Incident|date=2004|publisher=National Academies Press|isbn=978-0-309-09098-8|page=10|url=https://books.google.com/books?id=QcWbAgAAQBAJ&pg=PT24|language=en|url-status=live|archive-url=https://web.archive.org/web/20170918183801/https://books.google.ca/books?id=QcWbAgAAQBAJ&pg=PT24|archive-date=18 September 2017}}</ref><ref name=St2002/> It is a medication used for treating [[Medicine:Hyperthyroidism|hyperthyroidism]], in radiation emergencies, and for protecting the thyroid gland when certain types of [[Medicine:Radiopharmaceutical|radiopharmaceutical]]s are used.<ref name=AHFS2017/> In the third world it is also used for treating skin [[Medicine:Sporotrichosis|sporotrichosis]] and [[Medicine:Phycomycosis|phycomycosis]].<ref name=AHFS2017/><ref name=WHO2008>{{cite book | title = WHO Model Formulary 2008 | year = 2009 | isbn = 978-9-241-54765-9 | vauthors = ((World Health Organization)) | veditors = Stuart MC, Kouimtzi M, Hill SR | hdl = 10665/44053 |  publisher = World Health Organization |page=390 }}</ref> It is a supplement used by people with low dietary intake of [[Chemistry:Iodine|iodine]].<ref name=St2002/> It is administered orally.<ref name=AHFS2017>{{cite web|title=Potassium Iodide|url=https://www.drugs.com/monograph/potassium-iodide.html|publisher=The American Society of Health-System Pharmacists|access-date=8 January 2017|url-status=live|archive-url=https://web.archive.org/web/20170116192447/https://www.drugs.com/monograph/potassium-iodide.html|archive-date=16 January 2017}}</ref>

<!-- Side effects and mechanism -->
Common side effects include vomiting, diarrhea, abdominal pain, rash, and swelling of the salivary glands.<ref name=AHFS2017/> Other side effects include [[Medicine:Allergy|allergic reactions]], [[Medicine:Headache|headache]], [[Medicine:Goitre|goitre]], and [[Medicine:Depression (mood)|depression]].<ref name=WHO2008/> While use during [[Medicine:Pregnancy|pregnancy]] may harm the baby, its use is still recommended in radiation emergencies.<ref name=AHFS2017/> Potassium iodide has the [[Chemistry:Chemical formula|chemical formula]] [[Chemistry:Potassium|K]][[Chemistry:Iodide|I]].<ref>{{cite book| vauthors = Ensminger ME, Ensminger AH |title=Foods & Nutrition Encyclopedia, Two Volume Set|date=1993|publisher=CRC Press|isbn=9780849389801|page=16|edition=s|url=https://books.google.com/books?id=XMA9gYIj-C4C&pg=PA16|language=en|url-status=live|archive-url=https://web.archive.org/web/20170813144519/https://books.google.ca/books?id=XMA9gYIj-C4C&pg=PA16|archive-date=13 August 2017}}</ref> Commercially it is made by mixing [[Chemistry:Potassium hydroxide|potassium hydroxide]] with iodine.<ref>{{cite book| vauthors = Kaiho T |title=Iodine Chemistry and Applications|date=2014|publisher=John Wiley & Sons|isbn=978-1-118-87865-1 |page=57|url=https://books.google.com/books?id=tWrIBAAAQBAJ&pg=PA57|language=en|url-status=live|archive-url=https://web.archive.org/web/20170813150814/https://books.google.ca/books?id=tWrIBAAAQBAJ&pg=PA57|archive-date=13 August 2017}}</ref><ref>{{cite web | author = Center for Drug Evaluation and Research | title = Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies | url = https://www.fda.gov/regulatory-information/search-fda-guidance-documents/potassium-iodide-thyroid-blocking-agent-radiation-emergencies | date = December 2001 | publisher = U.S. Food and Drug Administration }}</ref>

<!-- History and culture -->
Potassium iodide has been used medically since at least 1820.<ref name=Or2012>{{cite book| vauthors = Oriel JD |title=The Scars of Venus: A History of Venereology|date=2012|publisher=Springer Science & Business Media|isbn=978-1-4471-2068-1|page=87|url=https://books.google.com/books?id=SevjBwAAQBAJ&pg=PA87|language=en|url-status=live|archive-url=https://web.archive.org/web/20170914035359/https://books.google.ca/books?id=SevjBwAAQBAJ&pg=PA87|archive-date=14 September 2017}}</ref> It is on the World Health Organization's List of Essential Medicines.<ref name="WHO21st">{{cite book | vauthors = ((World Health Organization)) | 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 }}</ref> Potassium iodide is available as a generic medication and over the counter.<ref name=Ric2015>{{cite book| vauthors = Hamilton R |title=Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition|date=2015|publisher=Jones & Bartlett Learning|isbn=978-1-284-05756-0|page=224}}</ref> Potassium iodide is also used for the iodization of salt.<ref name=St2002>{{cite book| vauthors = Stwertka A |title=A Guide to the Elements|date=2002|publisher=Oxford University Press, USA|isbn=978-0-19-515026-1 |page=137|url=https://books.google.com/books?id=JVktsSClpVcC&pg=PA137|language=en|url-status=live|archive-url=https://web.archive.org/web/20170914035401/https://books.google.ca/books?id=JVktsSClpVcC&pg=PA137|archive-date=14 September 2017}}</ref>

==Medical uses==

===Dietary supplement===

Potassium-iodide is a nutritional-supplement in animal feeds and also in the human diet. In humans it is the most common additive used for "iodizing" [[Chemistry:Sodium chloride|table salt]] (a public health measure to prevent [[Medicine:Iodine deficiency|iodine deficiency]] in populations that get little seafood). The oxidation of iodide causes slow loss of iodine content from [[Chemistry:Iodised salt|iodised salt]]s that are exposed to excess air. The alkali metal iodide salt, over time and exposure to excess oxygen and carbon dioxide, slowly oxidizes to metal carbonate and elemental iodine, which then evaporates.<ref>{{cite journal | vauthors = Waszkowiak K, Szymandera-Buszka K |title=Effect of storage conditions on potassium iodide stability in iodised table salt and collagen preparations |journal=International Journal of Food Science & Technology |volume=43 |issue=5 |pages=895–9 |doi=10.1111/j.1365-2621.2007.01538.x |year=2008}}</ref> [[Chemistry:Potassium iodate|Potassium iod''ate'']] ([[Chemistry:Potassium|K]][[Chemistry:Iodine|I]][[Chemistry:Oxygen|O<sub>3</sub>]]) is used to iodize some salts so that the iodine is not lost by oxidation. Dextrose or [[Chemistry:Sodium thiosulfate|sodium thiosulfate]] are often added to iodized table salt to stabilize potassium iodide thus reducing loss of the volatile chemical.<ref name=SI>{{cite web| url = http://www.saltinstitute.org/news-articles/iodized-salt/| publisher = Salt Institute| title = Iodized Salt| date = 13 July 2013| access-date = 13 June 2013| url-status = dead| archive-url = https://web.archive.org/web/20131016171353/http://www.saltinstitute.org/news-articles/iodized-salt/| archive-date = 16 October 2013}}</ref>

===Thyroid protection===
[[File:Pheochromocytoma Scan.jpg|thumb|upright|[[Medicine:Pheochromocytoma|Pheochromocytoma]] seen like a dark sphere in center of the body. Image is by MIBG scintigraphy with radiation from radioiodine in the MIBG. Note unwanted uptake of radioiodine from the pharmaceutical by the thyroid gland in the neck, in both images (front and back) of the same patient. Radioactivity is also seen in the bladder.]]
Thyroid iodine uptake blockade with potassium iodide is used in [[Medicine:Nuclear medicine|nuclear medicine]] scintigraphy and therapy with some radioiodinated compounds that are not targeted to the thyroid, such as [[Chemistry:Iobenguane|iobenguane]] (MIBG), which is used to image or treat neural tissue tumors, or iodinated [[Biology:Fibrinogen|fibrinogen]], which is used in fibrinogen scans to investigate clotting. These compounds contain iodine, but not in the iodide form. Since they may be ultimately metabolized or break down to radioactive iodide, it is common to administer non-radioactive potassium iodide to ensure that iodide from these radiopharmaceuticals is not sequestered by the normal affinity of the thyroid for iodide.

U.S. [[Organization:Food and Drug Administration|Food and Drug Administration]]-approved dosing of potassium iodide for this purpose with iobenguane, is as follows (per 24 hours): infants less than 1 month old, 16&nbsp;mg; children 1 month to 3 years, 32&nbsp;mg; children 3 years to 18 years, 65&nbsp;mg; adults 130&nbsp;mg.<ref>Kowalsky RJ, Falen, SW. Radiopharmaceuticals in Nuclear Pharmacy and Nuclear Medicine. 2nd ed. Washington DC: American Pharmacists Association; 2004.{{page needed|date=May 2012}}</ref> Some sources recommend alternative dosing regimens.<ref name="Olivier_2003">{{cite journal | vauthors = Olivier P, Colarinha P, Fettich J, Fischer S, Frökier J, Giammarile F, Gordon I, Hahn K, Kabasakal L, Mann M, Mitjavila M, Piepsz A, Porn U, Sixt R, van Velzen J | display-authors = 6 | title = Guidelines for radioiodinated MIBG scintigraphy in children | journal = European Journal of Nuclear Medicine and Molecular Imaging | volume = 30 | issue = 5 | pages = B45–B50 | date = May 2003 | pmid = 12658506 | doi = 10.1007/s00259-003-1138-9 | url = https://www.eanm.org/scientific_info/guidelines/gl_paed_mibg.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7 | s2cid = 20350450 | archive-url = https://web.archive.org/web/20070701011527/https://www.eanm.org/scientific_info/guidelines/gl_paed_mibg.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7 | archive-date = 1 July 2007 }}</ref>

Not all sources are in agreement on the necessary ''duration'' of thyroid blockade, although agreement appears to have been reached about the ''necessity'' of blockade for both scintigraphic and therapeutic applications of iobenguane. Commercially available iobenguane is labeled with [[Chemistry:Iodine-123|iodine-123]], and product labeling recommends administration of potassium iodide 1 hour prior to administration of the radiopharmaceutical for all age groups,<ref>{{cite web |url=http://nuclearpharmacy.uams.edu/resources/adreview.pdf |title = Highlight of Prescribing Information: AdreView Iobenguane I 123 Injection | publisher = GE Healthcare | date = September 2008 |access-date=23 March 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110823113112/http://nuclearpharmacy.uams.edu/resources/adreview.pdf |archive-date=23 August 2011 }}</ref> while the [[Organization:European Association of Nuclear Medicine|European Association of Nuclear Medicine]] recommends (for iobenguane labeled with either isotope), that potassium iodide administration begin one day prior to radiopharmaceutical administration, and continue until the day following the injection, with the exception of new-borns, who do not require potassium iodide doses following radiopharmaceutical injection.<ref name="Olivier_2003"/><ref name="NUREG1250">{{cite web |url=http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1250/ | work = US Nuclear Regulatory Commission | title = Report on the Accident at the Chernobyl Nuclear Power Station, NUREG-1250. |access-date=22 May 2012 |url-status=live |archive-url=https://web.archive.org/web/20120708022907/http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1250/ |archive-date=8 July 2012 }}</ref>

Product labeling for diagnostic [[Physics:Iodine-131|iodine-131]] iobenguane recommends potassium iodide administration one day before injection and continuing 5 to 7 days following administration, in keeping with the much longer half-life of this isotope and its greater danger to the thyroid.<ref>Iobenguane Sulfate I 131 Injection Diagnostic package insert. Bedford, MA: CIS-US, Inc. July 1999.</ref> Iodine-131 iobenguane used for therapeutic purposes requires a different pre-medication duration, beginning 24–48 hours prior to iobenguane injection and continuing 10–15 days following injection.<ref name="pmid18274745">{{cite journal | vauthors = Giammarile F, Chiti A, Lassmann M, Brans B, Flux G | title = EANM procedure guidelines for 131I-meta-iodobenzylguanidine (131I-mIBG) therapy | journal = European Journal of Nuclear Medicine and Molecular Imaging | volume = 35 | issue = 5 | pages = 1039–1047 | date = May 2008 | pmid = 18274745 | doi = 10.1007/s00259-008-0715-3 | url = https://www.eanm.org/scientific_info/guidelines/gl_radio_ther_benzyl.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7 | url-status = dead | s2cid = 6884201 | archive-url = https://web.archive.org/web/20111007202042/https://www.eanm.org/scientific_info/guidelines/gl_radio_ther_benzyl.pdf | archive-date = 7 October 2011 }}</ref>

===Nuclear accidents===
{{Main|Chemistry:Lugol's iodine}}
{| class="wikitable" style = "float: right; margin-left:15px; text-align:center"
|+ WHO recommended dose for radiological emergencies involving radioactive iodine<ref name="WHO_Guidelines">{{cite web|title=Guidelines for Iodine Prophylaxis following Nuclear Accidents|publisher=[[Organization:World Health Organization|World Health Organization]]|url=https://www.who.int/ionizing_radiation/pub_meet/Iodine_Prophylaxis_guide.pdf|year=1999|url-status=live|archive-url=https://web.archive.org/web/20130813071324/http://www.who.int/ionizing_radiation/pub_meet/Iodine_Prophylaxis_guide.pdf|archive-date=13 August 2013}}</ref>
! scope="col" | Age
! scope="col" | KI in mg per day
|-
| Over 12 years old
| style="text-align: center" | 130
|-
| 3 – 12 years old
| style="text-align: center" | 65
|-
| 1 – 36 months old
| style="text-align: center" | 32
|-
| < 1 month old
| style="text-align: center" | 16
|}
In 1982, the U.S. [[Organization:Food and Drug Administration|Food and Drug Administration]] approved potassium iodide to protect [[Biology:Thyroid|thyroid]] glands from radioactive iodine involving accidents or fission emergencies. In an accidental event or attack on a [[Engineering:Nuclear power plant|nuclear power plant]], or in [[Physics:Nuclear fallout|nuclear bomb fallout]], volatile fission product radionuclides may be released. Of these products, {{SimpleNuclide|iodine|131|link=yes}} (Iodine-131) is one of the most common and is particularly dangerous to the thyroid gland because it may lead to [[Medicine:Thyroid cancer|thyroid cancer]].<ref>{{cite journal | vauthors = von Hippel F | title = Potassium iodide for thyroid protection | journal = Science | volume = 218 | issue = 4578 | pages = 1174, 1177 | date = December 1982 | pmid = 7146900 | doi = 10.1126/science.7146900 | bibcode = 1982Sci...218.1174V }}</ref> By saturating the body with a source of stable iodide prior to exposure, inhaled or ingested {{SimpleNuclide|iodine|131}} tends to be excreted, which prevents radioiodine uptake by the thyroid. According to one 2000 study "KI administered up to 48 h before {{SimpleNuclide|iodine|131}} exposure can almost completely block thyroid uptake and therefore greatly reduce the thyroid absorbed dose. However, KI administration 96 h or more before {{SimpleNuclide|iodine|131}} exposure has no significant protective effect. In contrast, KI administration after exposure to radioiodine induces a smaller and rapidly decreasing blockade effect."<ref>{{cite journal | vauthors = Zanzonico PB, Becker DV | title = Effects of time of administration and dietary iodine levels on potassium iodide (KI) blockade of thyroid irradiation by 131I from radioactive fallout | journal = Health Physics | volume = 78 | issue = 6 | pages = 660–667 | date = June 2000 | pmid = 10832925 | doi = 10.1097/00004032-200006000-00008 | s2cid = 30989865 }}</ref> According to the FDA, KI should not be taken as a preventative before radiation exposure. Since KI protects for approximately 24 hours, it must be dosed daily until a risk of significant exposure to radioiodine no longer exists.<ref>{{cite journal | url=https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/frequently-asked-questions-potassium-iodide-ki | title=Frequently Asked Questions on Potassium Iodide (KI) | journal=FDA | date=24 March 2022 }}</ref>

Emergency 130 milligrams potassium iodide doses provide 100&nbsp;mg iodide (the other 30&nbsp;mg is the potassium in the compound), which is roughly 700 times larger than the normal nutritional need (see recommended dietary allowance) for iodine, which is 150 micrograms (0.15&nbsp;mg) of iodine (as iodide) per day for an adult. A typical tablet weighs 160&nbsp;mg, with 130&nbsp;mg of potassium iodide and 30&nbsp;mg of excipients, such as binding agents.

Potassium iodide cannot protect against any other mechanisms of radiation poisoning, nor can it provide any degree of protection against dirty bombs that produce radionuclides other than those of iodine.

The potassium iodide in iodized salt is insufficient for this use.<ref name=who-japan>{{cite web|title=FAQs: Japan nuclear concerns|url=https://www.who.int/hac/crises/jpn/faqs/en/index6.html|publisher=World Health Organization|access-date=1 April 2011|url-status=dead|archive-url=https://web.archive.org/web/20110401222354/http://www.who.int/hac/crises/jpn/faqs/en/index6.html|archive-date=1 April 2011}}</ref>  A likely [[Chemistry:Lethal dose|lethal dose]] of salt (more than a kilogram<ref name=cfr>By {{CodeFedReg|21|184|1634}}, the maximum allowable concentration of iodine in salt in the U.S. is .01%</ref>) would be needed to equal the potassium iodide in one tablet.<ref name=nacl-msds>{{cite web|url=http://ptcl.chem.ox.ac.uk/MSDS/SO/sodium_chloride.html|title=Safety (MSDS) data for sodium chloride|access-date=2 April 2011|archive-url=https://web.archive.org/web/20071030033213/http://ptcl.chem.ox.ac.uk/MSDS/SO/sodium_chloride.html|archive-date=30 October 2007|url-status=dead}}</ref>

The [[Organization:World Health Organization|World Health Organization]] does not recommend KI prophylaxis for adults over 40 years, unless the radiation dose from inhaled radioiodine is expected to threaten thyroid function, because the KI side effects increase with age and may exceed the KI protective effects; "...unless doses to the thyroid from inhalation rise to levels threatening thyroid function, that is of the order of about 5 [[Physics:Gray (unit)|Gy]]. Such radiation doses will not occur far away from an accident site."<ref name="WHO_Guidelines"/>

The U.S. Department of Health and Human Services restated these two years later as "The downward KI (potassium iodide) dose adjustment by age group, based on body size considerations, adheres to the principle of minimum effective dose. The recommended standard (daily) dose of KI for all school-age children is the same (65&nbsp;mg). However, adolescents approaching adult size (i.e., >70&nbsp;kg [154&nbsp;lbs]) should receive the full adult dose (130&nbsp;mg) for maximal block of thyroid radioiodine uptake. Neonates ideally should receive the lowest dose (16&nbsp;mg) of KI."<ref name="HHS_Guidelines">{{cite web|url=https://www.nrc.gov/docs/ML1233/ML12339A632.pdf|title=Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies|publisher=U.S. Department of Health and Human Services Food and Drug Administration Center for Drug Evaluation and Research (CDER)|date=December 2001|url-status=live|archive-url=https://web.archive.org/web/20170415202737/https://www.nrc.gov/docs/ML1233/ML12339A632.pdf|archive-date=15 April 2017}}</ref>

==Side effects==
There is reason for caution with prescribing the ingestion of high doses of potassium iodide and iodate, because their unnecessary use can cause conditions such as the [[Medicine:Jod-Basedow phenomenon|Jod-Basedow phenomena]], trigger and/or worsen [[Medicine:Hyperthyroidism|hyperthyroidism]] and [[Medicine:Hypothyroidism|hypothyroidism]], and then cause temporary or even permanent thyroid conditions.{{citations needed|date=December 2023}} It can also cause [[Medicine:Sialadenitis|sialadenitis]] (an inflammation of the salivary gland), gastrointestinal disturbances, and rashes.{{citations needed|date=December 2023}} Potassium iodide is also not recommended for people with dermatitis herpetiformis and hypocomplementemic vasculitis&nbsp;– conditions that are linked to a risk of iodine sensitivity.<ref>{{cite web | work = U.S. Centers for Disease Control and Prevention | url = https://www.cdc.gov/nceh/radiation/emergencies/ki.htm | title = Facts about patassium-iodine | date = 10 November 2022 }}</ref>

There have been some reports of potassium iodide treatment causing swelling of the parotid gland (one of the three glands that secrete [[Biology:Saliva|saliva]]), due to its stimulatory effects on saliva production.<ref name="Pathophysiology">McCance; Huether. "Pathophysiology: The biological basis for disease in Adults and Children". 5th Edition. Elsievier Publishing{{page needed|date=May 2012}}</ref>

A saturated solution of KI (SSKI) is typically given orally in adult doses several times a day (5 drops of SSKI assumed to be {{Frac|1|3}}&nbsp;mL) for thyroid blockade (to prevent the thyroid from excreting thyroid hormone) and occasionally this dose is also used, when iodide is used as an expectorant (the total dose is about one gram KI per day for an adult). The anti-radioiodine doses used for {{SimpleNuclide|iodine|131}} uptake blockade are lower, and range downward from 100&nbsp; mg a day for an adult, to less than this for children (see table). All of these doses should be compared with the far lower dose of iodine needed in normal nutrition, which is only 150&nbsp;μg per day (150 micrograms, not milligrams).

At maximal doses, and sometimes at much lower doses, side effects of iodide used for medical reasons, in doses of 1000 times the normal nutritional need, may include: acne, loss of appetite, or upset stomach (especially during the first several days, as the body adjusts to the medication). More severe side effects that require notification of a physician are: fever, weakness, unusual tiredness, swelling in the neck or throat,{{citation needed|date=December 2023}} mouth sores, skin rash, nausea, vomiting, stomach pains, irregular heartbeat,{{citation needed|date=December 2023}} numbness or tingling of the hands or feet, or a metallic taste in the mouth.<ref>{{cite web |url=http://www.medicinenet.com/potassium_iodide-oral/article.htm |title=POTASSIUM IODIDE - ORAL (SSKI) side effects, medical uses, and drug interactions |publisher=Medicinenet.com |access-date=23 March 2011 |url-status=live |archive-url=https://web.archive.org/web/20110324221248/http://www.medicinenet.com/potassium_iodide-oral/article.htm |archive-date=24 March 2011 }}</ref>{{citation needed|date=December 2023}}

In the event of a radioiodine release the ingestion of prophylaxis potassium iodide, if available, or even iodate, would rightly take precedence over perchlorate administration, and would be the first line of defence in protecting the population from a radioiodine release. However, in the event of a radioiodine release too massive and widespread to be controlled by the limited stock of iodide and iodate prophylaxis drugs, then the addition of perchlorate ions to the water supply, or distribution of perchlorate tablets would serve as a cheap, efficacious, second line of defense against carcinogenic radioiodine bioaccumulation.

The ingestion of goitrogen drugs is, much like potassium iodide also not without its dangers, such as [[Medicine:Hypothyroidism|hypothyroidism]]. In all these cases however, despite the risks, the prophylaxis benefits of intervention with iodide, iodate or perchlorate outweigh the serious cancer risk from radioiodine bioaccumulation in regions where radioiodine has sufficiently contaminated the environment.

==Industrial uses==
KI is used with silver nitrate to make [[Chemistry:Silver iodide|silver iodide]] (AgI), an important chemical in film photography. KI is a component in some disinfectants and hair treatment chemicals. KI is also used as a fluorescence quenching agent in biomedical research, an application that takes advantage of collisional quenching of fluorescent substances by the iodide ion. However, for several fluorophores addition of KI in μM-mM concentrations results in increase of fluorescence intensity, and iodide acts as fluorescence enhancer.<ref>{{cite journal | vauthors = Chmyrov A, Sandén T, Widengren J | title = Iodide as a fluorescence quencher and promoter--mechanisms and possible implications | journal = The Journal of Physical Chemistry B | volume = 114 | issue = 34 | pages = 11282–11291 | date = September 2010 | pmid = 20695476 | doi = 10.1021/jp103837f | url = http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-26847 }}</ref>

Potassium iodide is a component in the electrolyte of [[Physics:Dye-sensitized solar cell|dye sensitised solar cell]]s (DSSC) along with iodine.

Potassium iodide finds its most important applications in organic synthesis mainly in the preparation of aryl iodides in the [[Chemistry:Sandmeyer reaction|Sandmeyer reaction]], starting from aryl amines. Aryl iodides are in turn used to attach aryl groups to other organics by nucleophilic substitution, with iodide ion as the leaving group.

==Chemistry==
Potassium iodide is an [[Physics:Ionic compound|ionic compound]] which is made of the following [[Physics:Ion|ion]]s: {{chem2|K+I-}}. It crystallises in the [[Chemistry:Sodium chloride|sodium chloride]] structure. It is produced industrially by treating KOH with iodine.<ref name=Ullmann/>

It is a white [[Chemistry:Salt|salt]], which is the most commercially significant iodide compound, with approximately 37,000 tons produced in 1985. It absorbs water less readily than [[Chemistry:Sodium iodide|sodium iodide]], making it easier to work with.

Aged and impure samples are yellow because of the slow oxidation of the salt to [[Chemistry:Potassium carbonate|potassium carbonate]] and elemental [[Chemistry:Iodine|iodine]].<ref name=Ullmann>{{cite book | vauthors = Lyday PA, Kaiho T | chapter =  Iodine and Iodine Compounds. | title = Ullmann's Encyclopedia of Industrial Chemistry | date = June 2000 | volume = 15 | pages = 1–3 | doi = 10.1002/14356007.a14_381 | isbn = 3527306730 }}</ref>
:<chem>4 KI + 2 CO2 + O2 -> 2 K2CO3 + 2 I2</chem>

===Inorganic chemistry===
Since the [[Chemistry:Iodide|iodide]] ion is a mild [[Chemistry:Redox|reducing agent]], {{chem2|I-}} is easily oxidised to [[Chemistry:Iodine|iodine]] ({{chem2|I2}}) by powerful [[Chemistry:Redox|oxidising agents]] such as [[Chemistry:Chlorine|chlorine]]:
:<chem>2 KI_{(aq)}{} + Cl2_{(aq)} -> 2 KCl_{(aq)}{} + I2_{(aq)}</chem>
This reaction is employed in the isolation of iodine from natural sources. Air will oxidize iodide, as evidenced by the observation of a purple extract when aged samples of KI are rinsed with [[Chemistry:Dichloromethane|dichloromethane]]. As formed under acidic conditions, hydriodic acid (HI) is a stronger reducing agent.<ref>{{cite book | vauthors = Greenwood NN, Earnshaw A | title = Chemistry of the Elements | publisher = Pergamon Press | location = Oxford, UK | date = 1984 | isbn = 978-0-08-022057-4 }} {{page needed|date=May 2012}}</ref><ref>{{cite book | title = Handbook of Chemistry and Physics | edition = 71st | publisher = CRC Press | location = Ann Arbor, Michigan | date = 1990 | oclc = 1079892637 }}</ref><ref>{{cite book | title = The Merck Index | edition = 7th | publisher = Merck & Co. | location = Rahway, New Jersey | date = 1960 | oclc = 679352005 }}{{page needed|date=May 2012}}</ref>

Like other iodide salts, {{math|KI}} forms [[Chemistry:Triiodide|triiodide]] ({{chem2|I3-}}) when combined with elemental [[Chemistry:Iodine|iodine]].
:<chem>KI_{(aq)}{} + I2_{(s)} -> KI3_{(aq)}</chem>
Unlike {{chem2|I2}}, {{chem2|I3-}} salts can be highly water-soluble. Through this reaction, [[Chemistry:Iodine|iodine]] is used in [[Chemistry:Redox|redox]] [[Chemistry:Titration|titration]]s. Aqueous {{chem2|KI3}}, "Lugol's solution", is used as a disinfectant and as an etchant for gold surfaces.

Potassium iodide and [[Chemistry:Silver nitrate|silver nitrate]] are used to make [[Chemistry:Silver(I) iodide|silver(I) iodide]], which is used for high speed [[Engineering:Photographic film|photographic film]] and for cloud seeding:
:<chem>KI_{(aq)}{} + 9AgNO3_{(aq)}  ->  AgI_{(s)}{} + KNO3_{(aq)}</chem>

===Organic chemistry===
KI serves as a source of iodide in [[Chemistry:Organic synthesis|organic synthesis]]. A useful application is in the preparation of aryl iodides from arenediazonium salts.<ref>{{cite book | vauthors = Wade LG |title=Organic chemistry |date=2003 |publisher=Prentice Hall |location=Upper Saddle River, N.J. |isbn=978-0-13-033832-7 |edition=5th | pages = 871–2 }}</ref><ref>{{cite book | vauthors = March J |title=Advanced Organic Chemistry: Reactions, Mechanisms, and Structure |date=1992 |publisher=Wiley |location=New York |isbn=978-0-471-58148-2 |edition=4th | pages = 670–1 }}</ref>

:[[Image:Sandmeyer reaction.svg|400px]]

KI, acting as a source of iodide, may also act as a nucleophilic catalyst for the alkylation of alkyl [[Chemistry:Chloride|chloride]]s, [[Chemistry:Bromide|bromide]]s, or [[Chemistry:Mesylate|mesylate]]s.

==History==
Potassium iodide has been used medically since at least 1820.<ref name=Or2012/> Some of the earliest uses included cures for [[Medicine:Syphilis|syphilis]],<ref name=Or2012/> [[Medicine:Lead poisoning|lead]] and [[Medicine:Mercury poisoning|mercury poisoning]].

===Chernobyl===
Potassium iodide's (KI) value as a radiation protective (thyroid blocking) agent was demonstrated following the Chernobyl nuclear reactor disaster in April 1986. A saturated solution of potassium iodide (SSKI) was administered to 10.5 million children and 7 million adults in {{wipe|Poland}}<ref name="HHS_Guidelines" /><ref name="AJM93">{{cite journal | vauthors = Nauman J, Wolff J | title = Iodide prophylaxis in Poland after the Chernobyl reactor accident: benefits and risks | journal = The American Journal of Medicine | volume = 94 | issue = 5 | pages = 524–532 | date = May 1993 | pmid = 8498398 | doi = 10.1016/0002-9343(93)90089-8 | url = https://zenodo.org/record/1253782 | type = Submitted manuscript }}</ref> as a preventative measure against accumulation of radioactive {{SimpleNuclide|iodine|131}} in the [[Biology:Thyroid|thyroid]] gland.

Reports differ concerning whether people in the areas immediately surrounding Chernobyl itself were given the supplement.<ref>{{cite report|url=http://www.ecolo.org/documents/documents_in_english/Causes.ChernobyJF.doc|format=doc| vauthors = Frot J |title=The Causes of the Chernobyl Event|publisher=Environmentalists for Nuclear Energy|others=Berol Robinson (trans.)|url-status=live|archive-url=https://web.archive.org/web/20120408134449/http://www.ecolo.org/documents/documents_in_english/Causes.ChernobyJF.doc|archive-date=8 April 2012}}</ref><ref name="NUREG1250" /> However the US Nuclear Regulatory Commission (NRC) reported, "thousands of measurements of I-131 (radioactive iodine) activity...suggest that the observed levels were lower than would have been expected had this prophylactic measure not been taken. The use of KI...was credited with permissible iodine content in 97% of the evacuees tested."<ref name="NUREG1250" />

With the passage of time, people living in irradiated areas where KI was not available have developed thyroid cancer at epidemic levels, which is why the US Food and Drug Administration (FDA) reported "The data clearly demonstrate the risks of thyroid radiation... KI can be used [to] provide safe and effective protection against thyroid cancer caused by irradiation."<ref name="FDA Talk Paper">{{cite web | publisher = US Food and Drug Administration | work = FDA Talk Paper | title = Guidance on Protection Against Thyroid Cancer in Case of a Nuclear Accident | date = 3 December 2015 | url = https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/fda-talk-paper-guidance-protection-children-and-adults-against-thyroid-cancer-case-nuclear-accident }}</ref>

Chernobyl also demonstrated that the need to protect the thyroid from radiation was greater than expected. Within ten years of the accident, it became clear that thyroid damage caused by released radioactive iodine was virtually the only adverse health effect that could be measured. As reported by the NRC, studies after the accident showed that "As of 1996, except for thyroid cancer, there has been no confirmed increase in the rates of other cancers, including leukemia, among the... public, that have been attributed to releases from the accident."<ref name="NRC">{{cite web |url=http://www.nrc.gov/reading-rm/doc-collections/commission/secys/2002/secy2002-0089/attachment1.pdf | work = US Nuclear Regulatory Commission | title = Assessment of the Use of Potassium Iodide (KI) As a Public Protective Action During Severe Reactor Accidents Quoting Thyroid Cancer in Children of Belarus Following the Chernobyl Accident, NUREG-1633  |access-date=22 May 2012 |url-status=live |archive-url=https://web.archive.org/web/20090514120412/http://www.nrc.gov/reading-rm/doc-collections/commission/secys/2002/secy2002-0089/attachment1.pdf |archive-date=14 May 2009 }} {{page needed|date=May 2012}}</ref>

But equally important to the question of KI is the fact that radioactivity releases are not "local" events. Researchers at the World Health Organization accurately located and counted the residents with cancer from Chernobyl and were startled to find that "the increase in incidence [of thyroid cancer] has been documented up to 500 km from the accident site... significant doses from radioactive iodine can occur hundreds of kilometers from the site, beyond emergency planning zones."<ref name="WHO_Guidelines" />  Consequently, far more people than anticipated were affected by the radiation, which caused the United Nations to report in 2002 that "The number of people with thyroid cancer... has exceeded expectations. Over 11,000 cases have already been reported."<ref name="OCHA">{{cite report | publisher = United Nations | work = Office for the Coordination of Humanitarian Affairs (OCHA) | title = Chernobyl, a Continuing Catastrophe | location = New York and Geneva | date = 2000 | url = https://www.sortirdunucleaire.org/IMG/pdf/ocha-2000-chernobyl_a_continuing_catastrophe.pdf | page = 5 }}</ref>

===Hiroshima and Nagasaki===
The Chernobyl findings were consistent with studies of the effects of previous radioactivity releases. In 1945, several hundreds of thousands of people working and residing in the Japanese cities of Hiroshima and Nagasaki were exposed to high levels of radiation after [[Engineering:Nuclear weapon|atomic bombs]] were detonated over the two cities by the United States. Survivors of the A-bombings, also known as ''[[Biology:Hibakusha|hibakusha]]'', have markedly high rates of thyroid disease; a 2006 study of 4091 ''hibakusha'' found nearly half the participants (1833; 44.8%) had an identifiable thyroid disease.<ref>{{cite journal | vauthors = Imaizumi M, Usa T, Tominaga T, Neriishi K, Akahoshi M, Nakashima E, Ashizawa K, Hida A, Soda M, Fujiwara S, Yamada M, Ejima E, Yokoyama N, Okubo M, Sugino K, Suzuki G, Maeda R, Nagataki S, Eguchi K | display-authors = 6 | title = Radiation dose-response relationships for thyroid nodules and autoimmune thyroid diseases in Hiroshima and Nagasaki atomic bomb survivors 55-58 years after radiation exposure | journal = JAMA | volume = 295 | issue = 9 | pages = 1011–1022 | date = March 2006 | pmid = 16507802 | doi = 10.1001/jama.295.9.1011 | doi-access = free }}</ref>

An editorial in ''The Journal of the American Medical Association'' regarding thyroid diseases in both ''hibakusha'' and those affected by the Chernobyl disaster reports that "[a] straight line adequately describes the relationship between radiation dose and thyroid cancer incidence" and states "it is remarkable that a biological effect from a single brief environmental exposure nearly 60 years in the past is still present and can be detected."<ref name="AMA">{{cite journal | vauthors = Boice JD | title = Thyroid disease 60 years after Hiroshima and 20 years after Chernobyl | journal = JAMA | volume = 295 | issue = 9 | pages = 1060–1062 | date = March 2006 | pmid = 16507808 | doi = 10.1001/jama.295.9.1060 }}</ref>

===Nuclear weapons testing===
The development of thyroid cancer among residents in the North Pacific from radioactive fallout following the United States' nuclear weapons testing in the 1950s (on islands nearly 200 miles downwind of the tests) were instrumental in the 1978 decision by the [[Organization:Food and Drug Administration|FDA]] to issue a request for the availability of KI for thyroid protection in the event of a release from a commercial nuclear power plant or weapons-related nuclear incident. Noting that KI's effectiveness was "virtually complete" and finding that iodine in the form of KI was substantially superior to other forms including [[Chemistry:Potassium iodate|iodate (KIO<sub>3</sub>)]] in terms of safety, effectiveness, lack of side effects, and speed of onset, the FDA invited manufacturers to submit applications to produce and market KI.<ref name="US Fed. Reg.">{{cite journal|journal=US Federal Register|title=Federal Register|volume=43|issue=242|date=15 December 1978}}</ref>

===Fukushima===
It was reported on 16 March 2011, that potassium iodide tablets were given preventively to U.S. Naval air crew members flying within 70 nautical miles of the Fukushima Daiichi Nuclear Power Plant damaged in the earthquake (8.9/9.0 magnitude) and ensuing tsunami on 11 March 2011. The measures were seen as precautions, and the Pentagon said no U.S. forces have shown signs of radiation poisoning. By 20 March, the US Navy instructed personnel coming within 100 miles of the reactor to take the pills.<ref>{{cite news|url=http://www.cnn.com/2011/WORLD/asiapcf/03/22/japan.nuclear.reactors/index.html|title=Vegetables near stricken plant test high for radiation|date=22 March 2011|publisher=CNN|url-status=live|archive-url=https://web.archive.org/web/20121109153351/http://www.cnn.com/2011/WORLD/asiapcf/03/22/japan.nuclear.reactors/index.html|archive-date=9 November 2012}}</ref>

===The Netherlands===
[[File:Distributiegebieden-jodiumtabletten.png|thumb|Distribution areas for iodine pills in the Netherlands (2017).]]
In the Netherlands, the central storage of iodine-pills is located in Zoetermeer, near [[Place:The Hague|The Hague]]. In 2017, the Dutch government distributed pills to hundreds of thousands of residents who lived within a certain distance of nuclear power plants and met some other criteria.<ref>De Limburger (11 March 2016) [https://www.limburger.nl/cnt/dmf20160311_00011860/zes-vragen-over-half-miljoen-jodiumpillen six questions about a half of million iodine pills]</ref><ref>Dutch Government [https://www.rijksoverheid.nl/onderwerpen/straling/jodiumtabletten radiation iodine tablets]</ref>

=== Belgium ===
By 2020, potassium iodide tablets are made available free of charge for all residents in all pharmacies throughout the country.<ref>[https://www.nuclearrisk.be/get-iodine-tablets-pharmacy Get iodine tablets from the pharmacy] {{Webarchive|url=https://web.archive.org/web/20200630164642/https://www.nuclearrisk.be/get-iodine-tablets-pharmacy |date=30 June 2020 }}, website created as part of the information campaign 'Do you know what to do in case of a nuclear accident?' in March–May 2018, implementing the EU Directive 89/618 Euratom and the nuclear and radiological emergency plan for the Belgian territory.</ref>

==Formulations==
Three companies (Anbex, Inc., Fleming Co, and Recipharm of Sweden) have met the strict FDA requirements for manufacturing and testing of KI, and they offer products (IOSAT, ThyroShield, and ThyroSafe,<ref>{{cite book | vauthors = McFee RB, Leikin JB |title=Toxico-terrorism: emergency response and clinical approach to chemical, biological, and radiological agents | volume = 755 |date=2008 |publisher=McGraw-Hill Medical |location=New York |isbn=978-0-07-147186-2 |page=224 |url=https://books.google.com/books?id=pmjkst5T0AEC&q=%22thyrosafe%22&pg=PA224 |access-date=18 December 2010}}</ref> respectively) which are available for purchase. In 2012, Fleming Co. sold all its product rights and manufacturing facility to other companies and no longer exists. ThyroShield is currently not in production.

Tablets of potassium iodide are supplied for emergency purposes related to blockade of radioiodine uptake, a common form of radiation poisoning due to environmental contamination by the short-lived fission product {{SimpleNuclide|iodine|131}}.<ref>{{cite web |url=http://preparedness.com/potioddosgui.html |title=Potassium Iodide Dosage Guidelines & Frequently Asked Questions |publisher=Preparedness.com |date=10 December 2001 |access-date=23 March 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110317001850/http://preparedness.com/potioddosgui.html |archive-date=17 March 2011 }}</ref> Potassium iodide may also be administered pharmaceutically for [[Medicine:Thyroid storm|thyroid storm]].

For reasons noted above, therapeutic drops of SSKI, or 130&nbsp;mg tablets of KI as used for nuclear fission accidents, are not used as nutritional supplements, since an SSKI drop or nuclear-emergency tablet provides 300 to 700 times more iodine than the daily adult nutritional requirement. Dedicated nutritional iodide tablets containing 0.15&nbsp;mg (150 micrograms (μg)) of iodide, from KI or from various other sources (such as kelp extract) are marketed as supplements, but they are not to be confused with the much higher pharmaceutical dose preparations.

Potassium iodide can be conveniently prepared in a saturated solution, abbreviated SSKI. This method of delivering potassium iodide doesn't require a method to weigh out the potassium iodide, thus allowing it to be used in an emergency situation. KI crystals are simply added to water until no more KI will dissolve and instead sits at the bottom of the container. With pure water, the concentration of KI in the solution depends only on the temperature. Potassium iodide is highly soluble in water thus SSKI is a concentrated source of KI. At 20 degrees Celsius the solubility of KI is 140-148&nbsp;grams per 100&nbsp;grams of water.<ref>{{cite web |url=http://hazard.com/msds/mf/baker/baker/files/p5906.htm |title=Solubility of KI in water |publisher=Hazard.com |date=21 April 1998 |access-date=21 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20120423195709/http://hazard.com/msds/mf/baker/baker/files/p5906.htm |archive-date=23 April 2012 }}</ref> Because the volumes of KI and water are approximately additive, the resulting SSKI solution will contain about 1.00&nbsp;gram (1000&nbsp;mg) KI per milliliter (mL) of solution. This is 100% weight/volume (note units of [[Chemistry:Mass concentration|mass concentration]]) of KI (one gram KI per mL solution), which is possible because SSKI is significantly more dense than pure water—about 1.67 g/mL.<ref>{{cite journal |doi=10.1080/01916122.1993.9989424 |jstor=3687792 |title=Pollen purification and fractionation by equilibrium density gradient centrifugation |year=1993 | vauthors = Forster M, Flenley JR |journal=Palynology |volume=17 |issue=1 |pages=137–55|bibcode=1993Paly...17..137F }}</ref> Because KI is about 76.4% iodide by weight, SSKI contains about 764&nbsp;mg iodide per mL. This [[Chemistry:Mass concentration|concentration]] of iodide allows the calculation of the iodide dose per drop, if one knows the number of drops per milliliter. For SSKI, a solution more viscous than water, there are assumed to be 15 drops per mL; the iodide dose is therefore approximately 51&nbsp;mg per drop. It is conventionally rounded to 50&nbsp;mg per drop.

The term SSKI is also used, especially by pharmacists, to refer to a U.S.P. pre-prepared solution formula, made by adding KI to water to prepare a solution containing 1000&nbsp;mg KI per mL solution (100% wt/volume KI solution), to closely approximate the concentration of SSKI made by saturation. This is essentially interchangeable with SSKI made by saturation, and also contains about 50&nbsp;mg iodide per drop.

*Saturated solutions of potassium iodide can be an emergency treatment for [[Medicine:Hyperthyroidism|hyperthyroidism]] (so-called [[Medicine:Thyroid storm|thyroid storm]]), as high amounts of iodide temporarily suppress secretion of thyroxine from the thyroid gland.<ref>{{cite web | url = https://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-iodine.html | title = Iodine | archive-url = https://web.archive.org/web/20100804040405/http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-iodine.html | archive-date = 4 August 2010 | work = MedlinePlus | publisher = U.S. National Library of Medicine }}</ref> The dose typically begins with a loading dose, then {{Frac|1|3}}&nbsp;mL SSKI (5 drops or 250&nbsp;mg iodine as iodide), three times per day.
*Iodide solutions made from a few drops of SSKI added to drinks have also been used as expectorants to increase the water content of respiratory secretions and encourage effective coughing.<ref>{{cite web |url=http://www.uspharmacist.com/content/d/in-service/c/28732/ |title=Potassium Iodide: An Antidote for Radiation Exposure | vauthors = Saljoughian M |date=20 June 2011 |website=U.S. Pharmacist |access-date=29 January 2016 |url-status=live |archive-url=https://web.archive.org/web/20160205094735/http://www.uspharmacist.com/content/d/in-service/c/28732/ |archive-date=5 February 2016 }}</ref>
*SSKI has been proposed as a topical treatment for [[Medicine:Sporotrichosis|sporotrichosis]], but no trials have been conducted to determine the efficacy or side effects of such treatment.<ref>{{cite journal | vauthors = Xue S, Gu R, Wu T, Zhang M, Wang X | title = Oral potassium iodide for the treatment of sporotrichosis | journal = The Cochrane Database of Systematic Reviews | volume = 2009 | issue = 4 | pages = CD006136 | date = October 2009 | pmid = 19821356 | pmc = 7388325 | doi = 10.1002/14651858.CD006136.pub2 | veditors = Wu T }}</ref>
*Potassium iodide has been used for symptomatic treatment of [[Medicine:Erythema nodosum|erythema nodosum]] patients for persistent lesions whose cause remains unknown. It has been used in cases of erythema nodosum associated with [[Medicine:Crohn's disease|Crohn's disease]].<ref name="Marshall1997">{{cite journal | vauthors = Marshall JK, Irvine EJ | title = Successful therapy of refractory erythema nodosum associated with Crohn's disease using potassium iodide | journal = Canadian Journal of Gastroenterology  | volume = 11 | issue = 6 | pages = 501–502 | date = September 1997 | pmid = 9347164 | doi = 10.1155/1997/434989 | doi-access = free }}</ref>
*Due to its high potassium content, SSKI is extremely bitter, and if possible it is administered in a sugar cube or small ball of bread. It may also be mixed into much larger volumes of juices.
*Neither SSKI or KI tablets form nutritional supplements, since the nutritional requirement for iodine is only 150 micrograms (0.15&nbsp;mg) of iodide per day. Thus, a drop of SSKI provides 50/0.15 = 333 times the daily iodine requirement, and a standard KI tablet provides twice this much.

== References ==
{{Reflist}}

== External links ==
* {{cite web| url = https://druginfo.nlm.nih.gov/drugportal/rn/7681-11-0 | publisher = U.S. National Library of Medicine| work = Drug Information Portal| title = Potassium iodide }}
* [https://www.who.int/ionizing_radiation/pub_meet/en/Iodine_Prophylaxis_guide.pdf World Health Organization's guidelines for iodine prophylaxis following a nuclear accident]

{{Potassium compounds}}
{{Iodides}}
{{Antifungals}}
{{Antidotes}}
{{Radiation protection}}

{{DEFAULTSORT:Potassium Iodide}}
[[Category:Potassium compounds]]
[[Category:Alkali metal iodides]]
[[Category:Iodides]]
[[Category:Food additives]]
[[Category:Metal halides]]
[[Category:Photographic chemicals]]
[[Category:Radiobiology]]
[[Category:World Health Organization essential medicines]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Rock salt crystal structure]]

{{Sourceattribution|Potassium iodide}}