Characterizing the impact of magnesium and potassium-supplemented hydration with cisplatin and the subsequent electrolyte replacement requirements.

BACKGROUND: Cisplatin-associated electrolyte dysregulation is a prevalent therapy-related adverse effect. There are numerous electrolyte-supplemented hydration regimens that have been evaluated, however these studies focused on the development of nephrotoxicity. The objective of this study was to characterize the impact of magnesium and potassium-supplemented hydration during cisplatin administration on subsequent magnesium and potassium imbalances. METHODS: A single-region retrospective study from central Texas at Baylor Scott & White Cancer Clinics who were treated with two or more cycles of cisplatin were included. Standard hydration for this study was defined as normal saline before and after cisplatin along with potassium chloride 10 mEq and magnesium sulfate 1 g added to the cisplatin bag. RESULTS: A total of 477 patients were included in the study with376 patients receiving the standard hydration. Overall, 17 percent of patients experienced a potassium level below 3.5 mEq/L, but no major depletion was observed. Thirty-three percent of the patients experienced a magnesium level below 1.8 mg/dL, and time to first rescue magnesium supplementation was 4 weeks. CONCLUSION: Our study demonstrated despite routine magnesium and potassium supplementation in hydration, magnesium imbalances were observed. Potassium levels post cisplatin administration were maintained with minimal routine supplementation in hydration.

Severe and prolonged hypocalcemia after a single dose of denosumab for metastatic breast cancer with diffuse bone involvement without prior calcium/vitamin D supplementations.

INTRODUCTION: Denosumab is a human monoclonal antibody antiresorptive agent used for the treatment of bone metastasis in different cancer types, including breast cancer. Hypocalcemia is a known adverse effect of denosumab, and early supplementation plays an important role in the prevention and management of hypocalcemia. CASE REPORT: A 63-year-old female with stage IV estrogen receptor-positive breast cancer with diffuse bone metastasis experienced severe, prolonged hypocalcemia following a single dose of denosumab. The patient also had several risk factors for denosumab-associated hypocalcemia. Despite not receiving additional doses of denosumab, the patient required multiple hospitalizations and outpatient infusions of calcium to resolve her symptomatic hypocalcemia.Management and outcome: Severe hypocalcemia associated with denosumab can be prevented or mitigated by recognizing the risk factors for hypocalcemia and supplementing with vitamin D/calcium. Proposed risk factors include poor renal function, hypoparathyroidism, insufficient calcium intake, and diffuse metastatic bone disease. Studies suggest that early supplementation before starting denosumab can lower this risk. DISCUSSION: Several cases of severe hypocalcemia associated with denosumab have been reported. However, to the authors' knowledge, this is the first report that highlights the importance of early vitamin D/calcium supplementations for a patient with diffuse metastatic bone disease with pre-existing low levels of calcium.