Over-the-counter alkali agents to raise urine pH and citrate excretion: a prospective crossover study in healthy adults

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OBJECTIVE: To assess the effect of two over-the-counter alkalizing agents on 24-hour urinary parameters. MATERIALS AND METHODS: Ten healthy volunteers without a history of kidney stones were recruited to complete a baseline 24-hour urinalysis with a four-day diet inventory. Participants then maintained the same diet on either LithoLyte® (20 mEq two times per day) or KSPtabs (1 tablet two times per day) and submitted another 24-hour urinalysis. The process was repeated with the other supplement. Urinary alkali parameters were compared to baseline, and side effects were elicited with a questionnaire. RESULTS: LithoLyte® intake resulted in a non-significant increase in citrate (597 to 758 mg/day, p=0.058, an increase in urine pH (6.46 to 6.66, p=0.028), and a decrease in urine ammonium (41 to 36 mmol/day, p=0.005) compared to baseline. KSPtabs resulted in an increase in citrate (597 to 797 mg/day, p=0.037) and urine pH (6.46 to 6.86, p=0.037), with a non-significant decrease in ammonium (41 to 34 mmol/day, p=0.059). No significant differences were seen comparing urinary analytes between LithoLyte® and KSPtabs. With Litholyte®, no side effects, mild, moderate, and severe side effects were seen in 50%, 40%, 10%, and 0%, respectively. With KSPtabs, rates were 60%, 20%, 10%, and 10%, respectively. CONCLUSIONS: In healthy participants without a history of kidney stones, LithoLyte® and KSPtabs are effective over-the-counter alkali supplements, with a similar side effect profile to prescription potassium citrate.