You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology (MP07)1 Sep 2021MP07-11 OMEPRAZOLE LOWERS 24-HOUR URINARY MAGNESIUM EXCRETION IN PATIENTS WITH A HISTORY OF UROLITHIASIS: SINGLE CENTER EXPERIENCE Kristina L. Penniston, Shuang Li, Stephen Y. Nakada, and R. Allan Jhagroo Kristina L. PennistonKristina L. Penniston More articles by this author , Shuang LiShuang Li More articles by this author , Stephen Y. NakadaStephen Y. Nakada More articles by this author , and R. Allan JhagrooR. Allan Jhagroo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001980.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Urine magnesium (Mg) inhibits calcium oxalate (CaOx) stone formation. While highly variable, 24h urine Mg (UMg) is typically >2-fold higher than oxalate. Proton pump inhibitors, used for gastroesophageal reflux disease and peptic ulcer, inhibit active intestinal Mg absorption by interfering with transcellular cation channels. Alterations in Mg absorption are balanced by changes in renal Mg reabsorption. We hypothesized that patients taking omeprazole (OM) have lower UMg. METHODS: With IRB approval, we evaluated sequential patients with a history of urolithiasis seen in our multidisciplinary stone clinic or individually by the registered dietitian nutritionist (RDN). We documented clinical parameters, and OM dosage and duration of treatment if prescribed. We used 24h urine collections from patients′ initial encounters in stone clinic or with the RDN (ie, collected while naive to preventive therapy). Power analysis demonstrated the need for ≥240 subjects in order to identify significant differences in UMg for patients taking and not taking OM. RESULTS: Between 7/15/2020 and 1/15/2021, 325 patients were seen. We excluded for: no history of urolithiasis (n=9); no 24h urine collection prior to starting prevention (n=15); 24h urine creatinine <500 mg or >3,000 mg; initiation of pharmacological and/or nutrition therapy prior to starting OM (n=20). Patients (n=276) were 43% female and 91% white Caucasian. At their most recent clinical encounters, they were 58±14 y; calculated BMI was 31±8.2. Patients taking OM (OM+) for >3 months (n=45) took 24±8.2 mg/d (median 20 mg) and were taking it for 7.3 (median 6.4) y. Compared to those not taking OM (OM-; n=231), OM+ patients had lower UMg (figure). There were no differences for any other 24h urine stone risk parameters. As bowel disease is known to affect UMg, we examined this as a potential confounder. Though prevalence of bowel disease was different (figure), the prevalence of UMg ≤70 mg/d was not (figure; p=0.39, Chi square), suggesting bowel disease was not a confounder. CONCLUSIONS: Patients taking OM may absorb less Mg and have lower UMg, increasing their risk for CaOx stone recurrence. Studies are needed that investigate whether Mg supplementation reverses low UMg in patients taking OM and whether CaOx stone risk or recurrence is affected. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e143-e143 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kristina L. Penniston More articles by this author Shuang Li More articles by this author Stephen Y. Nakada More articles by this author R. Allan Jhagroo More articles by this author Expand All Advertisement Loading ...