Alkali citrate (also known as alkaline citrate) is an inhibitor of

kidney stones Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a calculus (medicine), solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the ...

. It is used to increase urine citrate levels - this prevents calcium oxalate stones by binding to calcium and inhibiting its binding to oxalate. It is also used to increase urine pH (alkalinize urine) - this prevents uric acid stones and cystine stones (which form in cystinuria). It is different than citric acid which is citrate bonded by hydrogen ions (or protons) making it acidic. Citric acid does not alkalinize urine as alkali citrate does. Alkali citrate replaces the protons with a non-acid positively charged ion like

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

Available forms

Alkaline citrate can be prescribed (K-citrate) or found as an over-the-counter (OTC) pill, liquid, or powder. For kidney stone prevention or alkalinization, it is most often accompanied by mineral(s) sodium or potassium. Less frequently,

magnesium citrate Magnesium citrate is a magnesium preparation in salt form with citric acid in a 1:1 ratio (1 magnesium atom per citrate molecule). The name "magnesium citrate" is ambiguous and sometimes may refer to other salts such as trimagnesium citrate wh ...

may be included. This results in compounds like Trimagnesium citrate, Tripotassium citrate and Trisodium citrate: *

Potassium citrate 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 ...

: K₃C₆H₅O₇ or C₆H₅K₃O₇ *

Trisodium citrate Trisodium citrate has the chemical formula of Na3C6H5O7. It is sometimes referred to simply as "sodium citrate", though sodium citrate can refer to any of the three sodium salts of citric acid. It possesses a saline, mildly tart flavor, and is a ...

: C₆H₅Na₃O₇ *

Magnesium citrate Magnesium citrate is a magnesium preparation in salt form with citric acid in a 1:1 ratio (1 magnesium atom per citrate molecule). The name "magnesium citrate" is ambiguous and sometimes may refer to other salts such as trimagnesium citrate wh ...

: C₁₂H₁₀Mg₃O₁₄ Citrus based beverages like

lemon juice The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China. The tree's ellipsoidal yellow fruit is used for culina ...

and

orange juice Orange juice is a liquid extract of the orange tree fruit, produced by squeezing or reaming oranges. It comes in several different varieties, including blood orange, navel oranges, valencia orange, clementine, and tangerine. As well as vari ...

may raise urine citrate, but much of the citrate is citric acid; without a cation like sodium, potassium or magnesium these beverages will have less effect on urine chemistry and therefore not aid in prevention of kidney stones as alkali citrate will.

Biological effects

Alkaline citrates are used to prevent recurrent calcium stone formation. This is one of the major types of kidney stones. The citrate salts can increase urine citrate, which binds with urine calcium, reduces supersaturation of calcium salts, and inhibits crystal formation. This helps prevent kidney stones. Oral alkali supplementation can also slow the rate of kidney function decline and “potentially reduce the risk of

end stage kidney disease Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...

(ESKD) in patients with chronic kidney disease (CKD) and

metabolic acidosis Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...

.” The compound also raises urine pH. When citrate is metabolized by the liver, it essentially generates

bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochem ...

, an important buffer. This reduces

uric acid Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown ...

supersaturation and prevents uric acid stones and cystine stones.

References

{{reflist Citrates