Potassium citrate

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Potassium citrate
Preferred IUPAC name
Tripotassium 2-hydroxypropane-1,2,3-tricarboxylate
3D model (JSmol)
ECHA InfoCard 100.011.596 Edit this at Wikidata
E number E332(ii) (antioxidants, ...)
  • InChI=1S/C6H8O7.3K/c7-3(8)1-6(13,5(11)12)2-4(9)10;;;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);;;/q;3*+1/p-3 checkY
  • InChI=1/C6H8O7.3K/c7-3(8)1-6(13,5(11)12)2-4(9)10;;;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);;;/q;3*+1/p-3
  • [K+].[K+].[K+].O=C([O-])CC(O)(C([O-])=O)CC(=O)[O-]
Molar mass 306.395 g/mol
Appearance white powder
Odor odorless
Density 1.98 g/cm3
Melting point 180 °C (356 °F; 453 K)[1]
Boiling point 230 °C (446 °F; 503 K)[1]
Solubility soluble in glycerin
insoluble in ethanol (95%)
Acidity (pKa) 8.5
A12BA02 (WHO)
Lethal dose or concentration (LD, LC):
170 mg/kg (IV, dog)
5400mg/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium citrate (also known as tripotassium citrate) is a potassium salt of citric acid with the molecular formula K3C6H5O7. It is a white, hygroscopic crystalline powder. It is odorless with a saline taste. It contains 38.28% potassium by mass. In the monohydrate form, it is highly hygroscopic and deliquescent.

As a food additive, potassium citrate is used to regulate acidity, and is known as E number E332. Medicinally, it may be used to control kidney stones derived from uric acid or cystine.

In 2020, it was the 297th most commonly prescribed medication in the United States, with more than 1 million prescriptions.[2][3]


Potassium citrate can be synthesized by the neutralization of citric acid which is achieved by the addition of potassium bicarbonate, potassium carbonate or potassium hydroxide to it. The solution can then be filtered and the solvent can be evaporated till granulation.


Potassium citrate is rapidly absorbed when given by mouth, and is excreted in the urine.[4] Since it is an alkaline salt, it is effective in reducing the pain and frequency of urination when these are caused by highly acidic urine.[5] It is used for this purpose in dogs and cats, but is chiefly employed as a non-irritating diuretic.

Potassium citrate is an effective way to treat/manage arrhythmia,[medical citation needed] if the patient is hypokalemic.

It is widely used to treat urinary calculi (kidney stones), and is often used by patients with cystinuria.[medical citation needed] A systematic review showed a significant reduction in the incidence of stone formation RR 0.26, 95% CI 0.10 to 0.68.[6]

It is also used as an alkalizing agent in the treatment of mild urinary tract infections, such as cystitis.[7]

It is also used in many soft drinks as a buffering agent.[8]

Frequently used in an aqueous solution with other potassium salts, it is a wet chemical fire suppressant that is particularly useful against kitchen fires.[9] Its alkaline pH encourages saponification to insulate the fuel from oxidizing air, and the endothermic dehydration reaction absorbs heat energy to reduce temperatures.[10][11]


Potassium citrate liquid is usually administered by mouth in a diluted aqueous solution, because of its somewhat caustic effect on the stomach lining, and the potential for other mild health hazards. Pill tablets also exist in normal, and extended-release formulations.


  1. ^ a b "Potassium Citrate". hazard.com. Archived from the original on 2017-08-15.{{cite web}}: CS1 maint: unfit URL (link)
  2. ^ "The Top 300 of 2020". ClinCalc. Retrieved 7 October 2022.
  3. ^ "Potassium Citrate - Drug Usage Statistics". ClinCalc. Retrieved 7 October 2022.
  4. ^ Medscape on hypocitraturia
  5. ^ Potassium Citrate for Kidney Stones
  6. ^ Phillips, Rebecca; Hanchanale, Vishwanath S; Myatt, Andy; Somani, Bhaskar; Nabi, Ghulam; Biyani, C Shekhar (6 October 2015). "Citrate salts for preventing and treating calcium containing kidney stones in adults". Cochrane Database of Systematic Reviews. 2015 (10): CD010057. doi:10.1002/14651858.CD010057.pub2. PMC 9578669. PMID 26439475.
  7. ^ "Potassium citrate for cystitis". patient.info.
  8. ^ "Soft Drinks with Potassium Citrate".
  9. ^ Fire, Impact. "What is a Class K Fire Extinguisher Used For?". resources.impactfireservices.com. Retrieved 2022-08-18.
  10. ^ US Fire extinguishing composition and method for fire extinguishing 5945025A, James A. Cunningham 
  11. ^ Xiaofang Wangy et al 2019 IOP Conf. Ser.: Mater. Sci. Eng. 490 022047

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