POTASSIUM IODIDE

EC Number 231-659-4 
CAS Number 7681-11-0

Synonyms:
POTASSIUM IODIDE; POTASYUM İYODÜR; Antistrumi; Iodide, Potassium; Ioduro Potasico Rovi; Iosat; Jod beta; Jodetten Henning; Jodgamma; Jodid; Jodid dura; Jodid Hexal; Jodid ratiopharm; Jodid; Verla; Jodid-ratiopharm; Mono Jod; Mono-Jod; Pima; Potassium Iodide; SSKI; Thyro Block; Thyro-Block; Thyroprotect; potassium iodide; 7681-11-0; Potassium iodide (KI); Pima; Kali iodide; Thyro-Block; Knollide; Kisol; Asmofug E; Potassium diiodide; Potassium monoiodide; Thyroshield; Joptone; Potide; Kalii iodidum; Iodure de potassium; Potassium iodide (K2I2); Potassium iodide (K(I2)); Tripotassium triiodide; Caswell No. 694; iodopotassium; K1-N; Potassium iodide (K3I3); UNII-1C4QK22F9J; HSDB 5040; EINECS 231-659-4; NSC 77362; EPA Pesticide Chemical Code 075701; AI3-52931; 1C4QK22F9J; CHEBI:8346; Potassium saltof hydriodic acid; MFCD00011405; Iosat; Potassium iodide solution; p otassiumiodide; Antistrumin; Thyrosafe; Kalium iodatum; Iodine Solution, 0.1N (N/10); Potassium iodide [JAN]; Kaliumiodid; potasium iodide; potassium iodid; Potassium iodide [USP:JAN]; potassium-iodide; CCRIS 8168; Thyroblock (TN); potassiumiodide ts; potassium ion iodide; Potassium Iodide,(S); ACMC-1BDBB; AC1Q1TQM; Nesslers Reagent Solution; Potassium Iodide USP/FCC; D02URS; WLN: KA I; EC 231-659-4; AC1L1J5K; AC1Q1TQ8; CHEMBL1141; DSSTox_CID_14836; DSSTox_RID_79208; DSSTox_GSID_34836; Potassium Iodide Neutral ACS; POTASSIUM IODIDE, ACS; KSC377K3H;Potassium iodide, ACS reagent; Potassium iodide (JP17/USP); Potassium iodide, 99% 50g; DTXSID7034836; CTK2H7533; Potassium iodide, LR, >=99%; MolPort-000-158-373; NLKNQRATVPKPDG-UHFFFAOYSA-M; HMS3651G04; CS-B1801; KS-000002OZ; NSC77362; Potassium iodide, AR, >=99.8%; Tox21_301293; ANW-46028; NSC-77362; s1897;Mercuric and potassium iodide solution; AKOS015833375; AKOS016371890; DB06715; LS-3213; LS41972; Potassium iodide, BioXtra, >=99.0%; RP22855; RTC-063831;TRA-0206473; NCGC00257542-01; Potassium iodide solution, 15 % (w/v); Potassium iodide, ReagentPlus(R), 99%; KB-59821; SC-18247; CAS-7681-11-0; Potassium;iodide, Vetec(TM) reagent grade; AB1002916; Potassium iodide, ACS reagent, >=99.0%; Potassium iodide, plant cell culture tested; TC-063831; TL8005264; FT-0645116; P1721; Potassium iodide, BioUltra, >=99.5% (AT); Potassium iodide, tested according to Ph.Eur.; C08219; D01016; Potassium iodide, SAJ first grade,>=99.5%; Y-9233; AB01274864-01; AB01568251_01; Potassium iodide, >=99.99% trace metals basis; Potassium iodide, JIS special grade, >=99.5%; Potassium iodide,purum p.a., >=99.0% (AT); I14-102509; Potassium iodide, puriss. p.a., ACS reagent, >=99.0% (AT); Potassium iodide, suitable for oxidant determination,>=99.5%; Potassium iodide, anhydrous, beads, -10 mesh, 99.998% trace metals basis; Potassium iodide, puriss. p.a., reag. ISO, reag. Ph. Eur.,>=99.5%;Potassium iodide, United States Pharmacopeia (USP) Reference Standard; Potassium iodide, anhydrous, free-flowing, Redi-Dri(TM), ACS reagent, >=99%;Potassium iodide, anhydrous, free-flowing, Redi-Dri(TM), ReagentPlus(R), 99%; Potassium Iodide, Pharmaceutical Secondary Standard; Certified ReferenceMaterial; 106449-25-6; 39448-53-8; 59216-96-5; 61456-02-8; Potassium iodide, puriss., meets analytical specification of Ph.??Eur. BP, USP, 99.0-100.5% (calc.to the dried substance); potasiyum iyodür; potasiyum iodür; potasium iodide; potasyum iodür; potasyum iodüre; potassıum ıodıde; potassium ıodıde; potasyum iodür

POTASSIUM IODIDE

Potassium Iodide is a metal halide composed of potassium and iodide with thyroid protecting and expectorant properties. Potassium iodide can block absorption of radioactive iodine by the thyroid gland through flooding the thyroid with non-radioactive iodine and preventing intake of radioactive molecules, thereby protecting the thyroid from cancer causing radiation. In addition, this agent acts as an expectorant by increasing secretion of respiratory fluids resulting in decreased mucus viscosity.

Potassium iodide

Potassium iodide is an odorless white solid. Sinks and mixes with water.

Potassium iodide is a metal iodide salt with a K(+) counterion. It is a scavenger of hydroxyl radicals. It has a role as a radical scavenger and an expectorant. It contains an iodide.

Potassium iodide
Potassium iodide.jpg
Potassium-iodide-3D-ionic.png
Clinical data
Trade names    iOSAT, SSKI, ThyroSafe, ThyroShield, others
AHFS/Drugs.com    Monograph
Pregnancy
category    
US: D (Evidence of risk)
ATC code    
R05CA02 (WHO) S01XA04 (WHO), V03AB21 (WHO)
Legal status
Legal status    
US: OTC
Identifiers
IUPAC name
CAS Number    
7681-11-0 
PubChem CID    
4875
DrugBank    
DB06715
ChemSpider    
4709
UNII    
1C4QK22F9J
KEGG    
D01016
ChEBI    
CHEBI:8346
ChEMBL    
ChEMBL1141
CompTox Dashboard (EPA)    
DTXSID7034836
ECHA InfoCard    100.028.782
Chemical and physical data
Formula    KI
Molar mass    166.0028
3D model (JSmol)    
Interactive image
Melting point    681 °C (1,258 °F)
Boiling point    1,330 °C (2,430 °F)
Solubility in water    1280 mg/mL (0 °C (32 °F))
1400 mg/mL (20 °C (68 °F))
1760 mg/mL (60 °C (140 °F))
2060 mg/mL (100 °C (212 °F))
[1]
NFPA 704 four-colored diamond
020
SMILES[show]
InChI[show]
Potassium iodide is a chemical compound, medication, and dietary supplement.[2][3] As a medication it is used to treat hyperthyroidism, in radiation emergencies, and to protect the thyroid gland when certain types of radiopharmaceuticals are used.[4] In the developing world it is also used to treat skin sporotrichosis and phycomycosis.[4][5] As a supplement it is used in those who have low intake of iodine in the diet.[3] It is given by mouth.[4]

Common side effects include vomiting, diarrhea, abdominal pain, rash, and swelling of the salivary glands.[4] Other side effects include allergic reactions, headache, goitre, and depression.[5] While use during pregnancy may harm the baby, its use is still recommended in radiation emergencies.[4] Potassium iodide has the chemical formula KI.[6] Commercially it is made by mixing potassium hydroxide with iodine.[7] [8]

Potassium iodide has been used medically since at least 1820.[9] It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.[10] Potassium iodide is available as a generic medication and over the counter.[11] In the United States a course of treatment is less than US$25.[11] Potassium iodide is also used for the iodization of salt.[3]

Medical uses
Dietary supplement
Potassium iodide is used as a nutritional supplement in animal feeds and also in the human diet. For the latter, it is the most common additive used to "iodize" table salt (a public health measure to prevent iodine deficiency in populations that get little seafood). The oxidation of iodide causes slow loss of iodine content from iodised salts 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.[12] Potassium iodate (KIO3) is used to add iodine to some salts so that the iodine is not lost by oxidation. Dextrose or sodium thiosulfate are often added to iodized table salt to stabilize potassium iodide thus reducing loss of the volatile chemical.[13]

Thyroid protection

Pheochromocytoma seen as dark sphere in center of the body. Image is by MIBG scintigraphy with radiation from radioiodine in the MIBG. However, 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 nuclear medicine scintigraphy and therapy with some radioiodinated compounds that are not targeted to the thyroid, such as iobenguane (MIBG), which is used to image or treat neural tissue tumors, or iodinated fibrinogen, which is used in fibrinogen scans to investigate clotting. These compounds contain iodine, but not in the iodide form. However, 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. 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 mg; children 1 month to 3 years, 32 mg; children 3 years to 18 years, 65 mg; adults 130 mg.[14] However, some sources recommend alternative dosing regimens.[15]

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 iodine-123, and product labeling recommends administration of potassium iodide 1 hour prior to administration of the radiopharmaceutical for all age groups,[16] while the 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.[15][17]

Product labeling for diagnostic 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.[18] 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.[19]

Nuclear accidents
WHO recommended dose for radiological emergencies involving radioactive iodine[20]
Age    KI in mg per day
Over 12 years old    130
3 – 12 years old    65
1 – 36 months old    32
< 1 month old    16
In 1982, the U.S. Food and Drug Administration approved potassium iodide to protect thyroid glands from radioactive iodine involving accidents or fission emergencies.[citation needed] In an accidental event or attack on a nuclear power plant, or in nuclear bomb fallout, volatile fission product radionuclides may be released. Of these products, 131
I
 (Iodine-131) is one of the most common and is particularly dangerous to the thyroid gland because it may lead to thyroid cancer.[citation needed] By saturating the body with a source of stable iodide prior to exposure, inhaled or ingested 131
I
 tends to be excreted, which prevents radioiodine uptake by the thyroid. According to one 2000 study "KI administered up to 48 h before 131
I
 exposure can almost completely block thyroid uptake and therefore greatly reduce the thyroid absorbed dose. However, KI administration 96 h or more before 131
I
 exposure has no significant protective effect. In contrast, KI administration after exposure to radioiodine induces a smaller and rapidly decreasing blockade effect."[21] For optimal prevention, KI must be dosed daily until a risk of significant exposure to radioiodine by either inhalation or ingestion no longer exists.[citation needed]

Emergency 130 milligrams potassium iodide doses provide 100 mg iodide (the other 30 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 mg) of iodine (as iodide) per day for an adult. A typical tablet weighs 160 mg, with 130 mg of potassium iodide and 30 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.[citation needed]

The potassium iodide in iodized salt is insufficient for this use.[22] A likely lethal dose of salt (more than a kilogram[23]) would be needed to equal the potassium iodide in one tablet.[24]

The 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 Gy. Such radiation doses will not occur far away from an accident site."[20]

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 mg). However, adolescents approaching adult size (i.e., >70 kg [154 lbs]) should receive the full adult dose (130 mg) for maximal block of thyroid radioiodine uptake. Neonates ideally should receive the lowest dose (16 mg) of KI."[25]

SSKI (i.e., the "saturated solution of KI" rather than tablets) may be used in radioiodine-contamination emergencies (i.e., nuclear accidents) to "block" the thyroid's uptake of radioiodine, at a dose of two drops of SSKI per day for an adult. This is not the same as blocking the thyroid's release of thyroid hormone, for which the adult dose is different (and is actually higher by a factor of 7 or 8[citation needed]), and for which KI anti-radiation pills (not a common medical treatment form of KI) are not usually available in pharmacies, or normally used in hospitals, or by physicians.[citation needed] Although the two forms of potassium iodide are completely interchangeable, normally in practice the SSKI solution, which is the historical medical form of high dose iodine, is generally used for all medical purposes save for radioiodine prophylaxis. For protection of the thyroid against radioiodine (iodine-131) contamination, the convenient standard 130 mg KI pill is used, if available.[citation needed] As noted, the equivalent two drops of SSKI (equaling the dose of one KI pill) may be used for this purpose, if the pills are not available.[citation needed]

Side effects
There is reason for caution with prescribing the ingestion of high doses of potassium iodide and iodate, as their unnecessary use can cause conditions such as the Jod-Basedow phenomena, trigger and/or worsen hyperthyroidism and hypothyroidism, and then cause temporary or even permanent thyroid conditions. It can also cause sialadenitis (an inflammation of the salivary gland), gastrointestinal disturbances, and rashes. Potassium iodide is also not recommended for people with dermatitis herpetiformis and hypocomplementemic vasculitis – conditions that are linked to a risk of iodine sensitivity.[26]

There have been some reports of potassium iodide treatment causing swelling of the parotid gland (one of the three glands that secrete saliva), due to its stimulatory effects on saliva production.[27]

A saturated solution of KI (SSKI) is typically given orally in adult doses several times a day (5 drops of SSKI assumed to be ​1⁄3 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 131
I
 uptake blockade are lower, and range downward from 100  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 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, mouth sores, skin rash, nausea, vomiting, stomach pains, irregular heartbeat, numbness or tingling of the hands or feet, or a metallic taste in the mouth.[28]

The use of a particular 'Iodine tablet' used in portable water purification has also been determined as somewhat effective at reducing radioiodine uptake. In a small study on human subjects, who for each of their 90-day trial, ingested four 20 milligram tetraglycine hydroperiodide (TGHP) water tablets, with each tablet releasing 8 milligrams (ppm) of free titratable iodine;[29] it was found that the biological uptake of radioactive iodine in these human subjects dropped to, and remained at, a value of less than 2% the radioiodine uptake rate of that observed in control subjects who went fully exposed to radioiodine without treatment.[30]

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 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.

Potassium iodide in its raw form is a mild irritant and should be handled with gloves. Chronic overexposure can have adverse effects on the thyroid. Potassium iodide is a possible teratogen.[citation needed]

Industrial uses
KI is used with silver nitrate to make 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.[31]

Potassium iodide is a component in the electrolyte of dye sensitised solar cells (DSSC) along with iodine.

Potassium iodide finds its most important applications in organic synthesis mainly in the preparation of aryl iodides in the 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 ionic compound which is made of the following ions: K+I−. It crystallises in the sodium chloride structure. It is produced industrially by treating KOH with iodine.[32]

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

Aged and impure samples are yellow because of the slow oxidation of the salt to potassium carbonate and elemental iodine.[32]

4 KI + 2 CO2 + O2 → 2 K2CO3 + 2 I2
Inorganic chemistry
Since the iodide ion is a mild reducing agent, I− is easily oxidised to I2 by powerful oxidising agents such as chlorine:

2 KI(aq) + Cl2(aq) → 2 KCl(aq) + I2(aq)
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 dichloromethane. As formed under acidic conditions, hydriodic acid (HI) is a stronger reducing agent.[33][34][35]

Like other iodide salts, KI forms I3− when combined with elemental iodine.

KI(aq) + I2(s) → KI3(aq)
Unlike I2, I3− salts can be highly water-soluble. Through this reaction, iodine is used in redox titrations. Aqueous KI3, "Lugol's solution", is used as a disinfectant and as an etchant for gold surfaces.

Potassium iodide and silver nitrate are used to make silver(I) iodide, which is used for high speed photographic film and for cloud-seeding:

KI(aq) + AgNO3(aq) → AgI(s) + KNO3(aq)
Organic chemistry
KI serves as a source of iodide in organic synthesis. A useful application is in the preparation of aryl iodides from arenediazonium salts.[36][37] For example:

Sandmeyer reaction.svg

KI, acting as a source of iodide, may also act as a nucleophilic catalyst for the alkylation of alkyl chlorides, bromides, or mesylates.

History
Potassium iodide has been used medically since at least 1820.[9] Some of the earliest uses included for syphilis.[9]

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 Poland[25][38] as a preventative measure against accumulation of radioactive 131
I
 in the thyroid gland.

Reports differ concerning whether people in the areas immediately surrounding Chernobyl itself were given the supplement.,[39][17] 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."[17]

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."[40]

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."[41]

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 cancer victims 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."[20] 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."[42]

Nagasaki
These findings were consistent with studies of the effects of previous radioactivity releases. In 1945, millions of Japanese were exposed to radiation from nuclear weapons, and the effects can still be measured. Today, nearly half (44.8%) the survivors of Nagasaki studied have identifiable thyroid disease, with an editorial in The Journal of the American Medical Association reporting "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."[43]

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 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 iodate (KIO3) 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.[44]

Fukushima
It was reported on March 16, 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 March 11, 2011. The measures were seen as precautions, and the Pentagon said no U.S. forces have shown signs of radiation poisoning. By March 20, the US Navy instructed personnel coming within 100 miles of the reactor to take the pills.[45]

The Netherlands

Distribution areas for iodine pills in the Netherlands (2017).
In the Netherlands, the central storage of iodine-pills is located in Zoetermeer, near 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.[46][47]

Belgium
As of 2020, potassium iodide tablets are made available free of charge for all residents in all pharmacies throughout the country.[48]

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,[49] 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. The Swedish manufacturing facility for Thyrosafe, a half-strength potassium iodide tablet for thyroid protection from radiation, was mentioned on the secret US 2008 Critical Foreign Dependencies Initiative leaked by Wikileaks in 2010.[50]

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 131
I
.[51] Potassium iodide may also be administered pharmaceutically for thyroid storm.

For reasons noted above, therapeutic drops of SSKI, or 130 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 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 as a saturated solution, abbreviated SSKI. This method of delivering potassium iodide does not require a method to weigh out the potassium iodide so it can 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 so SSKI is a concentrated source of KI. At 20 degrees Celsius the solubility of KI is 140-148 grams per 100 grams of water.[52] Because the volumes of KI and water are approximately additive, the resulting SSKI solution will contain about 1.00 gram (1000 mg) KI per milliliter (mL) of solution. This is 100% weight/volume (note units of 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.[53] Because KI is about 76.4% iodide by weight, SSKI contains about 764 mg iodide per mL. This 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 mg per drop. It is conventionally rounded to 50 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 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 mg iodide per drop.

Saturated solutions of potassium iodide can be an emergency treatment for hyperthyroidism (so-called thyroid storm), as high amounts of iodide temporarily suppress secretion of thyroxine from the thyroid gland.[54] The dose typically begins with a loading dose, then ​1⁄3 mL SSKI (5 drops or 250 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.[55]
SSKI has been proposed as a topical treatment for sporotrichosis, but no trials have been conducted to determine the efficacy or side effects of such treatment.[56]
Potassium iodide has been used for symptomatic treatment of erythema nodosum patients for persistent lesions whose cause remains unknown. It has been used in cases of erythema nodosum associated with Crohn's disease.[57]
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 are used as nutritional supplements, since the nutritional requirement for iodine is only 150 micrograms (0.15 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.

Properties of potassium iodide

Molecular Weight:166.003 g/mol
Boiling point:1325 °C (1013 hPa)
Density:3.23 g/cm3 (25 °C)
Melting Point:685 °C
Solubility:1430 g/l

 

 

  Potassium iodide (KI) is a salt of stable and nonradioactive iodine. It's known to help block radioactive iodine from being absorbed by the thyroid gland,the part of the body most sensitive to the mentioned substance. Once a person takes potassium iodide, stable iodine in the supplement or solution can beabsorbed in the thyroid.

  Since potassium iodide contains ideal amounts of stable iodine, the thyroid gland becomes "full" and can't absorb any form of iodine for the next 24 hours.

  Take note, however, that potassium iodide doesn't promise a 100 percent protection rate against radioactive iodine. There are three factors that can determine if protection to the thyroid gland can be increased, such as time after contamination, absorption and dose of radioactive iodine.

  Potassium iodide is taken orally, either as an oral solution, syrup, uncoated tablet or enteric-coated delayed release tablet. Note that the delayed release tablet generally isn't recommended because it can cause serious side effects.4 Potassium iodide is mainly used in the form of a saturated solution. This is prepared by reacting iodine with a hot solution of potassium hydroxide, and then added to water, fresh fruit juice or raw grass fed milk before drinking.

 

Potassium Iodide's Uses

  Potassium iodide is often used as an expectorant to help loosen and break up mucus in the airways. An expectorant allows the patient to cough up mucus so he or she can breathe more easily, especially if long-term lung problems such as asthma, chronic bronchitis or emphysema are present.

  Potassium iodide is also used with antithyroid medicines. Potassium iodide can assist in shrinking the size of the thyroid gland and decreasing the amount of thyroid hormones produced. This supplement may work for people who need to prepare the thyroid gland for surgical removal and address overactive thyroid conditions like hyperthyroidism.

  Meanwhile, a potassium iodide in iodine solution can be used in a radiation exposure emergency.8 As mentioned earlier, potassium iodide can block the thyroid from absorbing the radioactive iodine, helping protect it from damage. Ideally, this solution must be used along with other emergency measures that may be recommended.

  A saturated solution of potassium iodide was also shown to be potentially effective as an antifungal and help address external forms of cutaneous sporotrichosis, a fungal infection that can lead to skin lesions.

 

 

Side Effects of Potassium Iodide

Side effects can occur if you take potassium iodide. Although some complications are considered less common, consult your doctor if you notice these:

• Hives

• Joint pain

• Swelling of the arms, face, legs, lips, tongue and/or throat

• Swelling of lymph glands

 

  Other side effects that can occur because of potassium iodide supplements are diarrhea, nausea or vomiting and stomach pain. However, these do not usually

need medical attention and usually go away once the body adjusts to the supplement.

 

Health Benefits of Potassium Iodide

Numerous health benefits are attributed to potassium iodide, such as:

• Helps filter the body: Potassium iodide can help filter out harmful mercury, fluorides, chlorides and bromides from tissues and cells.

• Helping reduce arthritis risk: An iodine deficiency is linked to arthritis. Potassium iodide supplements may help people lower their risk for this disease.

• Promoting hormonal balance: Emotional disorders, malfunctioning glandular systems and weight gain associated with hormonal imbalance have been linked to an iodine deficiency. Potassium iodide supplements may help promote better hormonal health.

• Reducing chances of developmental problems: According to the World Health Organization, iodine deficiency is the biggest cause of mental retardation on a global scale.

   Because of this, many developing countries utilize potassium iodide supplements to lower the occurrence of growth and development problems such as goiter, Hashimoto's disease, Graves' disease, miscarriage, generalized fatigue and impaired immune system function.

• Contributing to overall healthy thyroid function: Potassium iodide is known as the thyroid mineral, and helps keep iodine levels in the thyroid balanced. If iodine levels in the body aren't optimized, this can cause either hyper or hypothyroidism, two conditions where the thyroid gland produces too much or too little iodine, respectively.

Potassium iodide serves as a treatment and preventive mechanism for these thyroid disorders by counteracting less-than-optimal iodine levels that occur because of dietary deficiencies. Furthermore, potassium iodide can aid in boosting colloid accumulation in the thyroid follicles by contributing to improved functioning.

 What is Potassium Iodide (KI)?
KI (potassium iodide) is a salt of stable (not radioactive) iodine that can help block radioactive iodine from being absorbed by the thyroid gland, thus protecting this gland from radiation injury.

The thyroid gland is the part of the body that is most sensitive to radioactive iodine.

People should take KI (potassium iodide) only on the advice of public health or emergency management officials. There are health risks associated with taking KI.

KI (potassium iodide) does not keep radioactive iodine from entering the body and cannot reverse the health effects caused by radioactive iodine once the thyroid is damaged.

KI (potassium iodide) only protects the thyroid, not other parts of the body, from radioactive iodine.
KI (potassium iodide) cannot protect the body from radioactive elements other than radioactive iodine—if radioactive iodine is not present, taking KI is not protective and could cause harm.

Table salt and foods rich in iodine do not contain enough iodine to block radioactive iodine from getting into your thyroid gland. Do not use table salt or food as a substitute for KI.

Do not use dietary supplements that contain iodine in the place of KI (potassium iodide). They can be harmful and non-efficacious. Only use products that have been approved by the U.S. Food and Drug Administration (FDA).

 

How KI works illustration
How does KI (potassium iodide) work?
The thyroid gland cannot tell the difference between stable and radioactive iodine. It will absorb both.

KI (potassium iodide) blocks radioactive iodine from entering the thyroid. When a person takes KI, the stable iodine in the medicine gets absorbed by the thyroid. Because KI contains so much stable iodine, the thyroid gland becomes “full” and cannot absorb any more iodine—either stable or radioactive—for the next 24 hours.

KI (potassium iodide) may not give a person 100% protection against radioactive iodine. Protection will increase depending on three factors.

Time after contamination: The sooner a person takes KI, the more time the thyroid will have to “fill up” with stable iodine.
Absorption: The amount of stable iodine that gets to the thyroid depends on how fast KI is absorbed into the blood.
Dose of radioactive iodine: Minimizing the total amount of radioactive iodine a person is exposed to will lower the amount of harmful radioactive iodine the thyroid can absorb.
 

who can take KI illustration
 

Who can take KI (potassium iodide)?
The thyroid glands of a fetus and of an infant are most at risk of injury from radioactive iodine. Young children and people with low amounts of iodine in their thyroid are also at risk of thyroid injury.

Infants (including breast-fed infants)

Infants have the highest risk of getting thyroid cancer after being exposed to radioactive iodine. All infants, including breast-fed infants need to be given the dosage of KI (potassium iodide) recommended for infants.

Infants (particularly newborns) should receive a single dose of KI. More than a single dose may lead to later problems with normal development. Other protective measures should be used.
In cases where more than one dose is necessary, medical follow up may be necessary.
Children

The U.S. Food and Drug Administration (FDA) recommends that all children internally contaminated with (or likely to be internally contaminated with) radioactive iodine take KI (potassium iodide), unless they have known allergies to iodine (contraindications).

Young Adults

The FDA recommends that young adults (between the ages of 18 and 40 years) internally contaminated with (or likely to be internally contaminated with) radioactive iodine take the recommended dose of KI (potassium iodide). Young adults are less sensitive to the effects of radioactive iodine than are children.

Pregnant Women

Because all forms of iodine cross the placenta, pregnant women should take KI (potassium iodide) to protect the growing fetus. Pregnant women should take only one dose of KI following internal contamination with (or likely internal contamination with) radioactive iodine.

Breastfeeding Women

Women who are breastfeeding should take only one dose of KI (potassium iodide) if they have been internally contaminated with (or are likely to be internally contaminated with) radioactive iodine. They should be prioritized to receive other protective action measures.

Adults

Adults older than 40 years should not take KI (potassium iodide) unless public health or emergency management officials say that contamination with a very large dose of radioactive iodine is expected.

Adults older than 40 years have the lowest chance of developing thyroid cancer or thyroid injury after contamination with radioactive iodine.
Adults older than 40 are more likely to have allergic reactions to or adverse effects from KI.
 

How KI is given
 

How is KI (potassium iodide) given?
The FDA has approved two different forms of KI (potassium iodide), tablets and liquid, that people can take by mouth after a radiation emergency involving radioactive iodine.

Tablets come in two strengths, 130 milligram (mg) and 65 mg. The tablets have lines on them so that they may be cut into smaller pieces for lower doses.

For the oral liquid solution, each milliliter (mL) contains 65 mg of KI (potassium iodide).

According to the FDA, the following doses are appropriate to take after internal contamination with (or likely internal contamination with) radioactive iodine:

Newborns from birth to 1 month of age should be given 16 mg (¼ of a 65 mg tablet or ¼ mL of solution). This dose is for both nursing and non-nursing newborn infants.
Infants and children between 1 month and 3 years of age should take 32 mg (½ of a 65 mg tablet OR ½ mL of solution). This dose is for both nursing and non-nursing infants and children.
Children between 3 and 18 years of age should take 65 mg (one 65 mg tablet OR 1 mL of solution). Children who are adult size (greater than or equal to 150 pounds) should take the full adult dose, regardless of their age.
Adults should take 130 mg (one 130 mg tablet OR two 65 mg tablets OR two mL of solution).
Women who are breastfeeding should take the adult dose of 130 mg.
 

KI dosage clock illustration
 

How often should KI (potassium iodide) be taken?
Taking a stronger dose of KI (potassium iodide), or taking KI more often than recommended, does not offer more protection and can cause severe illness or death.

A single dose of KI (potassium iodide) protects the thyroid gland for 24 hours. A one-time dose at recommended levels is usually all that is needed to protect the thyroid gland.

In some cases, people can be exposed to radioactive iodine for more than 24 hours. If that happens, public health or emergency management officials may tell you to take one dose of KI (potassium iodide) every 24 hours for a few days.

Avoid repeat dosing with KI (potassium iodide) for pregnant and breastfeeding women and newborn infants.

 

KI side effects illustration
 

What are the side effects of KI (potassium iodide)?
Side effects of KI (potassium iodide) may include stomach or gastro-intestinal upset, allergic reactions, rashes, and inflammation of the salivary glands.

When taken as recommended, KI (potassium iodide) can cause rare adverse health effects related to the thyroid gland.

These rare adverse effects are more likely if a person:

Takes a higher than recommended dose of KI
Takes the drug for several days
Has a pre-existing thyroid disease.
Newborn infants (less than 1 month old) who receive more than one dose of KI (potassium iodide) are at risk for developing a condition known as hypothyroidism (thyroid hormone levels that are too low). If not treated, hypothyroidism can cause brain damage.

Infants who receive more than a single dose of KI should have their thyroid hormone levels checked and monitored by a doctor.
Avoid repeat dosing of KI to newborns.
 

Where to get KI
 

Where can I get KI (potassium iodide)?
KI (potassium iodide) is available without a prescription. The Food and Drug Administration (FDA)external icon External Web Site Icon has approved some brands of KI.

People should only take KI (potassium iodide) on the advice of public health or emergency management officials. There are health risks associated with taking KI.

 Molecular Weight of potassium iodide    166.003 g/mol    Computed by PubChem 2.1 (PubChem release 2019.06.18)
Hydrogen Bond Donor Count of potassium iodide    0    Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Hydrogen Bond Acceptor Count of potassium iodide    1    Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Rotatable Bond Count of potassium iodide    0    Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Exact Mass of potassium iodide    165.86818 g/mol    Computed by PubChem 2.1 (PubChem release 2019.06.18)
Monoisotopic Mass of potassium iodide    165.86818 g/mol    Computed by PubChem 2.1 (PubChem release 2019.06.18)
Topological Polar Surface Area of potassium iodide    0 Ų    Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Heavy Atom Count of potassium iodide    2    Computed by PubChem
Formal Charge of potassium iodide    0    Computed by PubChem
Complexity of potassium iodide    2    Computed by Cactvs 3.4.6.11 (PubChem release 2019.06.18)
Isotope Atom Count of potassium iodide    0    Computed by PubChem
Defined Atom Stereocenter Count of potassium iodide    0    Computed by PubChem
Undefined Atom Stereocenter Count of potassium iodide    0    Computed by PubChem
Defined Bond Stereocenter Count of potassium iodide    0    Computed by PubChem
Undefined Bond Stereocenter Count of potassium iodide    0    Computed by PubChem
Covalently-Bonded Unit Count of potassium iodide    2    Computed by PubChem
Compound  of potassium iodide Is Canonicalized    Yes