MON-741 Development of Vitamin D Toxicity from Inappropriate Use of Over-The-Counter Supplements

Abstract Disclosure: K. Feng: None. S. Ozair: None. S.E. French: None. Vitamin D is essential for maintaining bone health, enhancing muscle function, and supporting overall metabolic balance. Additionally, this contributes to immune health, cardiovascular health, and cancer prevention. For those with vitamin D deficiency, oral supplementation has become widely prescribed. However, vitamin D toxicity occurs from exposure to extremely high doses of vitamin D supplementation by incorrect dosing, either accidentally or intentionally. A 67 year-old female presented to the hospital with altered mental status, nausea and vomiting, but no bone pain. Labs show hypercalcemia 14.8 mg/dL, elevated creatinine 2.4 mg/dL, hypokalemia 2.9 mmol/L, vitamin D 25-OH >240 ng/mL, elevated vitamin D 1,25 dihydroxy 88.5pg/mL, low PTH 15.3 pg/mL, and normal PTHrp 2.5 pmol/L. She received IVF and electrolyte replacement. Eventually, her mental status and kidney function returned back to baseline. No malignant causes of hypercalcemia were identified. Upon further history taking, she revealed taking over-the-counter supplementation of both Vitamin D 10,000 Units and calcium citrate 600 mg twice a day “for years”. Patient was advised to stop these supplements. After 3 weeks of not taking any supplements, the repeat blood work showed vitamin D 25-hydroxy 185.2 ng/mL, PTH 18 pg/mL, calcium 10.6 mg/dL. Over-the-counter supplements, such as vitamin D and calcium, are readily available in stores but excessive intake can lead to serious health complications. Symptoms of intoxication primarily manifest through symptoms of hypercalcemia, which can include anorexia, nausea, vomiting, weakness, constipation, polyuria, polydipsia, and dehydration. Severe cases can lead to complications such as nephrocalcinosis, hypertension, irreversible renal insufficiency, arrhythmias, and ultimately death. In all cases of hypercalcemia, it is essential to consider vitamin D intoxication and further educate patients on the proper use of supplementation. Presentation: Monday, July 14, 2025