From the Guidelines
Potassium citrate supplements work by providing an alkali load that increases urinary citrate excretion and raises urinary pH, thereby inhibiting the formation of kidney stones, particularly calcium stones, as demonstrated in a study published in The Journal of Urology in 2014 1. The mechanism of action of potassium citrate involves increasing the urinary citrate levels, which helps to prevent the formation of calcium stones by binding to calcium in the urine and reducing the amount of calcium available to form stones.
- Key points about potassium citrate supplements include:
- They are preferred over sodium citrate due to the potential of sodium to increase urine calcium excretion 1.
- Potassium citrate therapy is associated with a reduced risk of recurrent calcium stones in patients with low or low normal 24-hour urinary citrate excretion 1.
- The supplements can also benefit calcium phosphate stone formers with hypocitraturia, as citrate is a potent inhibitor of calcium phosphate crystallization 1.
- Additionally, potassium citrate can increase urinary pH, making it beneficial for patients with uric acid and cystine stones, as the solubility of these stones is increased at higher urinary pH values 1.
- The evidence from the studies suggests that potassium citrate supplements are effective in preventing kidney stone formation, particularly in patients with low urinary citrate levels, and can be used as a treatment option for patients with recurrent calcium stones, as well as those with uric acid and cystine stones, as supported by a study published in Kidney International in 2006 1.
From the FDA Drug Label
When Potassium Citrate is given orally, the metabolism of absorbed citrate produces an alkaline load. The induced alkaline load in turn increases urinary pH and raises urinary citrate by augmenting citrate clearance without measurably altering ultrafilterable serum citrate Thus, Potassium Citrate therapy appears to increase urinary citrate principally by modifying the renal handling of citrate, rather than by increasing the filtered load of citrate. The increased filtered load of citrate may play some role, however, as in small comparisons of oral citrate and oral bicarbonate, citrate had a greater effect on urinary citrate In addition to raising urinary pH and citrate, Potassium Citrate increases urinary potassium by approximately the amount contained in the medication. Increased citrate in the urine, by complexing with calcium, decreases calcium ion activity and thus the saturation of calcium oxalate Citrate also inhibits the spontaneous nucleation of calcium oxalate and calcium phosphate (brushite).
The mechanism of action of Potassium (K+) supplements (potassium citrate) is:
- Modification of renal handling of citrate: Potassium Citrate increases urinary citrate by augmenting citrate clearance without altering ultrafilterable serum citrate.
- Production of an alkaline load: Metabolism of absorbed citrate produces an alkaline load, increasing urinary pH.
- Complexation with calcium: Increased citrate in the urine complexing with calcium, decreases calcium ion activity and saturation of calcium oxalate.
- Inhibition of spontaneous nucleation: Citrate inhibits the spontaneous nucleation of calcium oxalate and calcium phosphate (brushite) 2.
From the Research
Mechanism of Action of Potassium Citrate
The mechanism of action of potassium citrate supplements involves several key aspects:
- Increasing urinary citrate and pH levels, which helps to reduce the saturation and propensity for spontaneous nucleation of calcium oxalate 3, 4
- Restoring normal urinary citrate levels, which can help to inhibit new stone formation 3, 4
- Decreasing urinary saturation of calcium oxalate, which can help to reduce the risk of stone formation 3, 4
- Increasing urine pH, which can help to increase uric acid solubility and reduce the propensity for uric acid stone formation 4
Effects on Urine Chemistry
Potassium citrate supplementation can lead to complex changes in urine chemistry, including:
- Increased urine citrate, phosphate, and oxalate levels 5
- Decreased urine calcium levels 5
- Increased urine pH, which can lead to increased calcium oxalate and calcium phosphate supersaturation 5
- Reduced uric acid supersaturation 5
Comparison with Other Treatments
Potassium citrate has been compared to other treatments, such as lemonade therapy and potassium chloride supplementation:
- Lemonade therapy can increase urinary citrate and urine volumes, but potassium citrate with lemonade therapy may be more effective at increasing urinary citrate 6
- Potassium citrate supplementation may be superior to potassium chloride supplementation in patients receiving thiazide therapy, due to its ability to increase citrate complexation of calcium and reduce the propensity for spontaneous precipitation of calcium oxalate 7