Potassium citrate

Potassium salt with systemic alkalinising effect, used for kidney stone prevention and hypokalaemia

ATC code: A12BA02 (Potassium citrate)

Brand names

Urocit-K, Polycitra-K

Mechanism of action

Potassium citrate dissociates in the gut into potassium and citrate ions. Potassium replenishes plasma and intracellular K+. Citrate is metabolised in the liver to bicarbonate, which raises urinary pH and binds free urinary calcium ions into soluble complexes. The result is reduced urinary supersaturation with calcium oxalate and calcium phosphate, slowing growth of existing stones and reducing new stone formation. In distal renal tubular acidosis, potassium citrate compensates the systemic metabolic acidosis.

Indications

Kidney stone prevention

First line

Potassium citrate is first-line for prevention of recurrent calcium oxalate, uric acid and cystine stones in patients with hypocitraturia, low urinary pH or recurrent urolithiasis. The Cochrane review 2015 pooled 7 RCTs with 477 patients and showed citrate salts reduce new-stone risk by 75 % versus placebo or control (RR 0.25, 95 % CI 0.14–0.44). Guidelines AUA 2014, EAU 2024 and Spanish AEU 2024 recommend potassium citrate 30–60 mEq/day as first-line after 24-hour urine assessment. Targets: urinary citrate above 320 mg/day, urinary pH 6.0–7.0. In gouty uric-acid nephropathy allopurinol adds benefit. AEMPS registered Acalka with this indication.

Sources

Hypokalaemia (potassium deficiency)

First line

Potassium citrate is used in hypokalaemia, especially when concurrent metabolic acidosis must be corrected – for example in distal renal tubular acidosis, Fanconi syndrome or severe diarrhoea. In thiazide- or loop-diuretic-induced hypokalaemia, potassium chloride is usually preferred because chloride is co-lost. Doses are titrated to plasma K+ and symptom severity, typically 20–40 mEq two to three times daily. Repeat K+ within 3–7 days, monitor renal function and concurrent hyperkalaemia-risk drugs – ACE-I, ARBs, spironolactone, eplerenone, trimethoprim. Guidelines: KDIGO 2020 and Spanish SEN 2022.

Sources

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Official sources

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FDA / DailyMed

FDA — DailyMed Drug Labels

Label dated: 03/25/2026

Safety

Contraindications

Hyperkalaemia (K+ above 5.5 mmol/L)
Acute or chronic kidney injury with eGFR below 30 mL/min/1.73 m²
Addison disease
Upper or lower urinary tract obstruction
Severe dehydration
Metabolic alkalosis
Concurrent potassium-sparing diuretics (amiloride, triamterene, spironolactone, eplerenone)

Serious adverse effects

Hyperkalaemia with risk of ventricular arrhythmia, especially with ACE-I, ARBs, potassium-sparing diuretics or trimethoprim
Oesophageal and gastric ulceration with extended-release tablets if taken without enough water
Metabolic alkalosis in overdose
Intestinal perforation with strictures in patients on extended-release tablets

Common adverse effects

Nausea
Epigastric pain
Bloating
Diarrhoea at doses above 60 mEq/day
Metallic taste

PregnancyFDA C

Experience with potassium citrate in pregnancy is limited. It is used by clinical indication for hypokalaemia and recurrent stone disease. Pregnancy itself raises stone risk through hypercalciuria. Dose is titrated to plasma potassium with monitoring of renal function and urinary pH. AEMPS Acalka SmPC recommends use in pregnancy only when expected benefit outweighs risk.

Breastfeeding

Potassium is normally present in human milk; potassium citrate at therapeutic doses does not change infant levels. In lactation the drug is used by clinical indication with routine potassium monitoring.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Potassium citrate used for?

Potassium citrate is evaluated for the following indications with varying evidence strength: Kidney stone prevention (evidence tier A), Hypokalaemia (potassium deficiency) (evidence tier B). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Potassium citrate?

Common side effects of Potassium citrate (≥ 1 in 100): Nausea, Epigastric pain, Bloating, Diarrhoea at doses above 60 mEq/day, Metallic taste. See the Safety section for uncommon and serious reactions.

Is Potassium citrate safe during pregnancy?

FDA category C. Experience with potassium citrate in pregnancy is limited. It is used by clinical indication for hypokalaemia and recurrent stone disease. Pregnancy itself raises stone risk through hypercalciuria. Dose is titrated to plasma potassium with monitoring of renal function and urinary pH. AEMPS Acalka SmPC recommends use in pregnancy only when expected benefit outweighs risk.

Is Potassium citrate compatible with breastfeeding?

Who should not take Potassium citrate?

Potassium citrate is contraindicated in: Hyperkalaemia (K+ above 5.5 mmol/L); Acute or chronic kidney injury with eGFR below 30 mL/min/1.73 m²; Addison disease; Upper or lower urinary tract obstruction; Severe dehydration. Full list in the Safety section.

Mechanism of action

Indications

Kidney stone prevention

First line

Sources

Hypokalaemia (potassium deficiency)

First line

Sources

Safety

Contraindications

Hyperkalaemia (K+ above 5.5 mmol/L)
Acute or chronic kidney injury with eGFR below 30 mL/min/1.73 m²
Addison disease
Upper or lower urinary tract obstruction
Severe dehydration
Metabolic alkalosis
Concurrent potassium-sparing diuretics (amiloride, triamterene, spironolactone, eplerenone)

Serious adverse effects

Hyperkalaemia with risk of ventricular arrhythmia, especially with ACE-I, ARBs, potassium-sparing diuretics or trimethoprim
Oesophageal and gastric ulceration with extended-release tablets if taken without enough water
Metabolic alkalosis in overdose
Intestinal perforation with strictures in patients on extended-release tablets

Common adverse effects

Nausea
Epigastric pain
Bloating
Diarrhoea at doses above 60 mEq/day
Metallic taste

PregnancyFDA C

Breastfeeding

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Potassium citrate used for?

What are the side effects of Potassium citrate?

Is Potassium citrate safe during pregnancy?

Is Potassium citrate compatible with breastfeeding?

Who should not take Potassium citrate?