AUA 2023: State of the Art Lecture: Over-the-Counter Remedies for Recurrent Stone Formers: Where Is the Evidence?

( The 2023 American Urological Association (AUA) Meeting included a Saturday afternoon plenary session featuring a lecture on over-the-counter remedies for recurrent nephrolithiasis by Dr. Brett Johnson. He began his lecture by going over alkali therapy and citraturia, and speaking about how the alkali load is what ultimately increases urinary citrate. He then introduced potassium citrate as the most common prescription oral alkali therapy, but remarked on the medication’s high cost. Dr. Johnson spoke about causes that actually generate the alkali load, and highlighted differences between citric acid and potassium citrate.

Dr. Johnson gave a wonderful overview on current types of prescription alkali and the pros and cons of each, specifically regarding: potassium citrate, sodium bicarbonate, sodium citrate, calcium citrate, and magnesium citrate. He then introduced over the counter alternatives to these prescription drugs, and spoke about how recurrent stone-formers are aware of their physiological inclination to form stones. Before delving into the options, he established that the FDA generally does not regulate supplements.

In terms of supplement options, Dr. Johnson introduced the oral form of moonstone powder, Litholyte powder, Litholyte coffee, Kidney COP, KSP tabs, LithoBalance, and NOW Potassium Citrate. He nicel included a chart outlining the pH, advertised citrate (in mEq/serving), total citrate, and alkali citrate in each of them. The study was conducted by purchasing the over the counter supplement two times, 6 months apart, and calculating the citrate content via the pH and pKa method.

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In conclusion, Moonstone had the most alkali citrate per serving and NOW Potassium Citrate Powder was the cheapest. Litholyte Coffee and Moonstone were found to be the most expensive supplements in relation to alkali citrate content.

Dr. Johnson proceeded to speak about plant-based extracts as supplements. The two most recognizable ones, he said, are Chanca Piedra (Phyllanthus nirui) and Cystone. While limited data is available to adequately characterize if either of these plant based extracts are promising, Dr. Johnson noted a study conducted in Brazil by Pucci. Et al which demonstrated a statistically significant number of stones found by ultrasound after treatment with Phyllanthus. Limitations exist with this study, he notes, since ultrasound is not the best modality to identify stones and also that the mechanism of action of the plant is unclear.

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Finally, Dr. Johnson spoke about apple cider vinegar and noted that there is no direct evidence to support its use for stone prevention. Vinegar has been studied in China, and in a rat model it was shown that rats treated with vinegar saw a significant reduction in stone formation following administration of ethylene glycol. A human study was also done, showing an impressive clinical response in the treatment group during a prospective randomized study. He concluded his enlightening presentation by noting that Apple Cider Vinegar contains a large amount of acetic acid which is not likely to induce hypercitraturia through alkali load, but possibly has epigenetic influences on ion transport which is a topic for further research.


Presented by: Brett Johnson, MD, Assistant Professor, UT Southwestern Medical Center, Dallas, TX

Written By: Allen Rojhani, BS; MD Candidate at the Drexel University College of Medicine and 2022-2023 LIFT Research Fellow at the University of California, Irvine Department of Urology during the 2023 American Urological Association (AUA) Annual Meeting, Chicago, IL, April 27 – May 1, 2023