From the Guidelines
Magnesium citrate is generally not contraindicated in patients with kidney stones, but caution should be exercised in certain cases, as supported by the American College of Physicians guideline 1.
Key Considerations
- For most common types of kidney stones, such as calcium oxalate stones, magnesium citrate can be safely used and may even be beneficial in preventing constipation and potentially reducing the risk of certain types of kidney stones.
- However, in patients with magnesium-containing stones (struvite stones) or those with severe renal impairment, magnesium citrate should be avoided or used only under close medical supervision, as excess magnesium could potentially contribute to stone formation or cause magnesium toxicity in these specific cases.
- The American College of Physicians recommends pharmacologic monotherapy with a thiazide diuretic, citrate, or allopurinol to prevent recurrent nephrolithiasis in patients with active disease in which increased fluid intake fails to reduce the formation of stones 1.
Recommendations
- Patients with kidney stones should consult their healthcare provider to determine the type of kidney stone they have and to assess their overall kidney function before using magnesium citrate.
- The benefits of magnesium citrate in preventing constipation and potentially reducing the risk of certain types of kidney stones should be weighed against the risks in each individual case.
- Increased fluid intake is recommended to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis, as supported by low-quality evidence 1.
From the Research
Magnesium Citrate and Nephrolithiasis
- There is no direct evidence to suggest that magnesium citrate (Mg citrate) is contraindicated in patients with nephrolithiasis (kidney stones) 2, 3, 4, 5, 6.
- In fact, studies have shown that citrate salts, including magnesium citrate, can help prevent and treat calcium-containing kidney stones by increasing urinary citrate levels and reducing stone formation 3, 4, 5, 6.
- A study found that a combination of potassium-sodium citrate and magnesium oxide increased the excretion of citrate, magnesium, and potassium, and decreased the ion activity product index of calcium oxalate, making it more effective than either supplement alone in inhibiting the crystallization of calcium oxalate stones 5.
- Another study reported that 391 mg (21 meq) Mg daily as a mixed salt, Mg potassium citrate, reduced calcium stone recurrence by 90%, similar to potassium citrate, but with better gastrointestinal tolerance 6.
- However, it is essential to note that the quality of reported literature remains moderate to poor, and a well-designed statistically powered multi-centre RCT is needed to answer relevant questions concerning the efficacy of citrate salts, including magnesium citrate, in preventing and treating kidney stones 3.
Key Findings
- Citrate salts, including magnesium citrate, can help prevent and treat calcium-containing kidney stones 3, 4, 5, 6.
- Magnesium citrate may be beneficial in patients with nephrolithiasis, particularly those with hypocitraturia and/or hypomagnesuria 5, 6.
- The combination of potassium-sodium citrate and magnesium oxide may be more effective than either supplement alone in inhibiting the crystallization of calcium oxalate stones 5.