UCHealth Today Potassium iodide is in the news. Here’s what it’s all about.

Onemightfairlycomparethecurrentrunonpotassiumiodide–anonprescriptiondeliveryvehicleforlargedosesofdietaryiodine–withthatoftoiletpaperearlyinthecoronaviruspandemic.Whilethetwohaveratherdifferentends,themotivationofthepurchasersisthesame:stockingupincaseofemergency.

Anemergencyinvolvingpotassiumiodidewouldbeaseriousone:radioactivefalloutfromanuclearaccidentorexplosion.RussianPresidentVladimirPutin’swarinUkraine,withitsprosecutionbyanuclearpoweranditsinvolvementofUkrainiannuclearpowerplants(includingthedecommissioned,infamousChernobylreactorthatmelteddownin1986),hasraisedtheriskofnuclearradiationrelease,intentionalorotherwise.Hencethespikinginterestinpotassiumiodide.

Whatisiodine?

It’satracesoilmineralandmicronutrientimportantforproperthyroidfunction.It’sfoundinseafood,seaweeddairy,eggs,chicken,andbeefliver.Iodineisaddedasasupplementininfantformulaandtablesalt(hence“iodizedsalt”).TheNationalInstitutesofHealthrecommends150microgramsadayforadults,220microgramsadayforpregnantwomen,and290microgramsadayforbreastfeedingwomen.

WhathappensifIdon’tgetenoughdietaryiodine?

Thethyroidglandneedsiodinetoproducethyroidhormones,andthyroidactsasabodilymagnetforthemineral.Toolittleiodineriskshypothyroidismamongthoseconsuminglessthan10or20microgramsaday.Thisthrottlingofthyroidhormonescanaffectgrowthanddevelopmentinfetusesandchildren,impaircognition,sapenergy,andleadtogoiter.ThankstotheU.S.introductionofiodizedsaltinthe1920s,iodinedeficiencyisnowrareintheUnitedStates.

Whatispotassiumiodide(orpotassiumiodate)?

Potassiumiodide(KI)andpotassiumiodate(KIO₃)comeintabletsorliquidform.Theseiodinetabletsandliquidsdeliverlargedosesofiodine(65milligramsor130milligrams,so400to800timestheadultdailyrecommendedallowance).Falloutafteranuclearaccidentordetonationcanspreadradioactiveiodine(radioiodine).Athyroidglandinneedofiodinewillsweepradioactiveiodineup,andthatcancausethyroidcancerandotherthyroiddamage.Potassiumiodineorpotassiumiodate,so-called“thyroidblockers,”saturatethethyroidwithnonradioactiveiodineandpreventradioactiveiodineuptake.

Thedosedependsonageandistakenonceevery24hourswhileradiationexposurepersists.TheU.S.FoodandDrugAdministrationsayspotassiumiodideworksbestiftakenwithin3-4hoursofexposure.

Doiodinetabletsblockbodilyradiationingeneral?

No.Theyonlyprotectthethyroidgland.Iodinetabletswon’thelpwithradiationpoisoningorconsequencesofradiationexposurenothavingtodowithradioiodineinthethyroidgland.

Incaseofnuclear/radiationemergency,shouldeveryonetakeiodinetablets?

Thegoalofpotassiumiodideandpotassiumiodateistopreventlong-termthyroidproblemsandcancers,sopotassiumiodidetabletsandliquidsaremostimportantforinfants,children,youngadults,andpregnantandbreastfeedingwomen,accordingtotheCDC.TheCDCadvisesadultsoverage40againsttakingiodinetabletsunless“averylargedoseofradioactiveiodineisexpected,”becausethatcohorthas“thelowestchanceofdevelopingthyroidcancerorthyroidinjuryaftercontaminationwithradioactiveiodine.”

ShouldItakepotassiumiodide/potassiumiodateasaprecaution?

No.AccordingtotheU.S.CentersforDiseaseControlandPrevention:“PeopleshouldtakeKI(potassiumiodide)onlyontheadviceofpublichealthoremergencymanagementofficials.TherearehealthrisksassociatedwithtakingKI.”

Whatsortsofhealthrisksarewetalkingabout?

AccordingtotheCDC,sideeffectscanincludestomachorgastrointestinalupset,allergicreactions,rashes,andinflammationofthesalivaryglands.

I’veheardofradioiodinetherapyasatreatmentforthyroidcancer.True?

Yes.RadioactiveiodinetherapyusingI-131isawaytoharnessthethyroid’sthirstforiodinetokillthyroidcancercells.

Isitpossibletohaveaniodineallergy?

Theresearchsuggestsnot.

DoIneedtostockuponiodinetablets?

Let’shopenot.Butthey’retypicallyavailableatonlinedrugstores,Amazon,andelsewhere.

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