Abstract
Potassium citrate is one of the most commonly prescribed medications for kidney stone prevention. In vitro, it solubilizes calcium oxalate mineral complexes while inhibiting crystal growth and cellular adherence. In vivo, low doses can reduce calcium oxalate stone recurrence whereas high doses (“dissolution therapy”) can dissolve small uric acid stones by raising urine pH.
Despite its track record, potassium citrate is a hard pill to swallow long term (literally), because of factors such as cost, tolerability, efficacy, and side effects. 1 –3 Thus, Stern et al. reviewed the literature and queried their patients to identify eight of the more commonly used alkalinizing over-the-counter (OTC) supplements and foods—a topic of high importance to patients but rarely discussed by practitioners. The investigators compiled these alkalinizing agents into the easy-to-read Table 1. 4
From a practical standpoint, this article provides a good starting point for physicians and dieticians who interact with stone formers but may not be familiar with these product names. The alkaline content of these supplements is also valuable information, particularly for providers who may rely on them after a patient has failed first-line alkalinization therapies. Indeed, the low alkaline content in most of these products should discourage providers from recommending them or, at the least, inform providers and patients on the expected level of urinary alkalinization before purchase. More importantly, however, their discussion highlights the lack of peer-reviewed investigations and claims testing for many of these products, which is vital to recognize before use. Ultimately, from their low alkaline content to their lack of clinical vetting, alkalinizing OTC agents lack the “basics” of a good therapeutic alternative to potassium citrate.