Potassium chloride (medical use)

Clinical data
Pronunciation poe tass’ i um klor’ ide
Trade names Kay-Cee-L, Slow-K, others
AHFS/Drugs.com Professional Drug Facts
License data
Routes of


By mouth, intravenous
ATC code
Legal status
Legal status
CAS Number
PubChem CID
Chemical and physical data
Formula ClK
Molar mass 74.55 g·mol−1
3D model (JSmol)

Potassium chloride, also known as potassium salt, is used as a medication to treat and prevent low blood potassium.[1] Low blood potassium may occur due to vomiting, diarrhea, or certain medications.[2] The concentrated version should be diluted before use.[1] It is given by slow injection into a vein or by mouth.[3]

Side effects may include heart problems if given too quickly by injection into a vein.[3] By mouth it can result in abdominal pain, peptic ulcer disease, or gastrointestinal bleeding.[3] Greater care is recommended in those with kidney problems.[1] As long as high blood potassium does not occur, use in pregnancy or breastfeeding is believed to be safe for the baby.[4] Generally, the strength of the formulation for injection into a vein should not be greater than 40 mmol/L (3 mg/L).[3]

Potassium chloride came into large scale commercial use as a fertilizer in 1861 and has been used medically since the 1950s.[5][6] It is on the World Health Organization’s List of Essential Medicines.[7] Potassium chloride is available as a generic medication.[3] In 2020, it was the 33rd most commonly prescribed medication in the United States, with more than 17 million prescriptions.[8][9]

Medical use[edit]

Potassium chloride is used in the treatment of hypokalemia as an electrolyte replenisher.[10] With a molecular weight of approximately 75 and a valence of 1, the use of KCl for electrolytes makes 75 mg the equivalent of 1 mEq.

Some cardiac surgery procedures cannot be carried out on the beating heart. For these procedures, the surgical team will bypass the heart with a heart-lung machine and inject potassium chloride into the heart muscle to stop the heartbeat.

Side effects[edit]

Side effects can include gastrointestinal discomfort, including nausea and vomiting, diarrhea, and bleeding of the digestive tract.

Overdoses cause hyperkalemia, which can lead to paresthesia, cardiac conduction blocks, fibrillation, arrhythmias, and sclerosis.[11]

Because of the risk of small-bowel lesions, the US FDA requires some potassium salts containing more than 99 mg (about 1.3 mEq) to be labeled with a warning,[12] while recommending an adult daily intake of 4700 mg (about 63 mEq).


Slow-K is a 1950s development where the medicine is formulated to enter the bloodstream at delayed intervals. It was first only prescribed to British military forces to balance their diets while serving in Korea.[13]


Brand names[edit]

Brand names include K-Dur, Klor-Con, Micro-K, Slow-K, Sando-K, and Kaon Cl.

Lethal injection[edit]

Potassium chloride is used in lethal injection as the third of a three-drug combination. KCl is also sometimes used in fetal intracardiac injections in second- and third-trimester induced abortions.[14][15] Jack Kevorkian’s thanatron machine injected a lethal dose of potassium chloride into the patient, which caused the heart to stop functioning, after a sodium thiopental-induced coma was achieved.[16]

Cardiac arrest induced by potassium has been used in political assassinations in Iran, by injection or by inserting a potassium suppository into the victim’s rectum.[17]


  1. ^ a b c World Health Organization (2009). Stuart MC, Kouimtzi M, Hill SR (eds.). WHO Model Formulary 2008. World Health Organization. p. 491. hdl:10665/44053. ISBN 9789241547659.
  2. ^ “Potassium chloride medical facts from Drugs.com”. www.drugs.com. Archived from the original on 18 January 2017. Retrieved 14 January 2017.
  3. ^ a b c d e British national formulary : BNF 69 (69 ed.). British Medical Association. 2015. pp. 680, 684. ISBN 9780857111562.
  4. ^ “Klor-Con M – FDA prescribing information, side effects and uses”. www.drugs.com. Archived from the original on 18 January 2017. Retrieved 14 January 2017.
  5. ^ Velde, Pierre; Barré, Pierre (2009). Soils, Plants and Clay Minerals: Mineral and Biologic Interactions. Springer Science & Business Media. p. 275. ISBN 9783642034992. Archived from the original on 18 September 2017.
  6. ^ BNA’s Patent, Trademark & Copyright Journal. Bureau of National Affairs, Incorporated. 1991. Archived from the original on 18 September 2017.

    Potassium chloride, used since the 1950s for the treatment of potassium depletion in humans

  7. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  8. ^ “The Top 300 of 2020”. ClinCalc. Retrieved 7 October 2022.
  9. ^ “Potassium – Drug Usage Statistics”. ClinCalc. Retrieved 7 October 2022.
  10. ^ Hypokalemia in Emergency Medicine~treatment at eMedicine
  11. ^ Hyperkalemia in Emergency Medicine at eMedicine
  12. ^ “Office of Dietary Supplements – Potassium”. ods.od.nih.gov. Archived from the original on 11 August 2022. Retrieved 15 August 2022.
  13. ^ He, F. J.; Markandu, N. D.; Coltart, R.; Barron, J.; MacGregor, G. A. (2005). “Effect of Short-Term Supplementation of Potassium Chloride and Potassium Citrate on Blood Pressure in Hypertensives”. Hypertension. 45 (4): 571–4. doi:10.1161/01.HYP.0000158264.36590.19. PMID 15723964.
  14. ^ Stubblefield, Phillip G.; Carr-Ellis, Sacheen; Borgatta, Lynn (2004). “Methods for Induced Abortion”. Obstetrics & Gynecology. 104 (1): 174–85. doi:10.1097/01.AOG.0000130842.21897.53. PMID 15229018.
  15. ^ Types of Abortion Procedures Archived 18 April 2009 at the Wayback Machine. Americanpregnancy.org (20 September 2011). Retrieved on 16 February 2012.
  16. ^ Boyes, Roger (29 March 2008). “Death for hire – suicide machine lets you push final button”. The Times. Archived from the original on 3 September 2016. Retrieved 14 January 2017.
  17. ^ Sahimi, Muhammad. “The Chain Murders: Killing Dissidents and Intellectuals, 1988-1998”. pbs.org. FRONTLINE. Archived from the original on 11 December 2016. Retrieved 27 November 2016.

External links[edit]

  • “Potassium chloride”. Drug Information Portal. U.S. National Library of Medicine.

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