Ronald L. Castelino

Background Calcium‐alkali syndrome (CAS) is characterised by hypercalcaemia, metabolic alkalosis, and renal injury. CAS has been a long‐standing concern but has fallen off the radar in recent times. However, supplementation of calcium and vitamin D for osteoporosis, and use of calcium based antacids for reflux has led to its resurgence as one of the leading causes for hypercalcaemia‐induced hospitalisations. Aim We present a case of CAS owing to excessive consumption of calcium carbonate in the presence of vitamin D. Clinical details An 84‐year‐old woman presented to the hospital emergency room for the second time in 4 months after CAS was missed during the first admission. A history of significant (6–8 tablets daily) Quick‐Eze use (calcium carbonate), Gaviscon dual action antacid (calcium carbonate 32.5 mg/mL, sodium bicarbonate 21.3 mg/mL, sodium alginate 50 mg/mL) for reflux, and 2000 IU of vitamin D capsules for osteoporosis was the likely reason for CAS. COVID‐19 lockdown and the inability to fill esomeprazole scripts had increased the patient's reliance on over‐the‐counter treatments for reflux. Outcomes The severe hypercalcaemia was treated using intravenous fluids and pamidronate, following which her serum calcium levels normalised, with resolution of symptoms. Conclusion The effect of Quick‐Eze tablets on the development of hypercalcaemia should not be underestimated, especially in the presence of interacting medicines or supplements. This report highlights the importance of accurate history taking as the hypercalcaemia was missed during the patient's initial visit. Appropriate warning labels are warranted on Quick‐Eze tablets, as the current information is ambiguous, with no specific information on duration.