<p><strong>In adult and pediatric patients with uric acid or calcium-based stones, clinicians may offer over-the-counter alkali products to raise urinary pH and/or urinary citrate. (<em>Expert Opinion)</em></strong></p>
Discussion
Discussion
<p>Several over-the-counter alkali products are available that raise urinary pH and/or urinary citrate. These products vary in their formulation (e.g., liquid, tablet, powder, and/or effervescent formulation), the provided cation (e.g., potassium, sodium, hydrogen, magnesium, calcium, others), the accompanying anion (e.g., citrate, bicarbonate, malate, others), and other added components (e.g., oxalate, vitamin B6).<sup>231</sup> While some of these alternative agents can effectively increase urinary citrate and pH with effects comparable to prescription potassium citrate in short-term studies,<sup>232-234</sup> a major limitation is the lack of long-term stone recurrence data. Generally, potassium-based preparations are preferred over sodium-based alternatives due to the potential for sodium-induced urinary calcium excretion<sup>187</sup> and the greater solubility of potassium urate compared with sodium urate. On the other hand, low-potassium preparations may be considered to achieve therapeutic urinary pH and/or citrate levels in patients with hyperkalemia or in those who develop hyperkalemia on potassium-based preparations. Citric acid-based preparations are not recommended as a source of alkali since they do not deliver an alkali load and do not raise urinary citrate or pH.<sup>188</sup></p>