Multiple Myeloma and Renal Health: Navigating Selected Clinical Complexities.

Multiple myeloma (MM) is a hematologic malignancy characterized by clonal plasma cell proliferation and is typically associated with excess monoclonal immunoglobulin production. MM results in multisystem complications that significantly impact morbidity and mortality if left unrecognized or improperly managed. Renal dysfunction is one of the most impactful complications and occurs through multiple mechanisms, requiring careful management of treatment complications, medication safety issues, and negative impacts on prognosis. This review examines the pathophysiology, diagnostic evaluation, pharmacologic management, and pharmacist-led supportive care strategies for MM-related renal dysfunction. MM can result in renal injury through various mechanisms. The monoclonal immunoglobulin-related kidney diseases discussed in this review include cast nephropathy and monoclonal immunoglobulin deposition disease (MIDD). Cast nephropathy arises from the toxic accumulation of free light chains (FLCs) produced by clonal plasma cells. MIDD results in non-amyloid immunoglobulin deposition along various renal basement membranes. MM may also cause renal injury through non-immunoglobulin-related mechanisms, such as hypercalcemia-associated nephropathy (HAN). HAN results from elevated serum calcium levels and often occurs in patients with MM who have a high skeletal tumor burden. Early diagnosis requires prompt utilization of serum and urine testing, FLC assessment, imaging, and bone marrow evaluation. Pharmacologic management must effectively control the disease while aiming for remission and ensuring patient safety. Factoring in complications such as renal impairment is critical to optimizing therapy. Bortezomib-based therapy, dose-adjusted immunomodulatory agents, careful use of bone-modifying therapies, hydration, avoidance of nephrotoxins, and electrolyte monitoring are essential components of care. Pharmacists are pivotal in identifying renal risk, adjusting medication regimens, preventing nephrotoxic exposure, educating patients, and coordinating multidisciplinary interventions. Early recognition and targeted management can improve or, in some cases, reverse renal complications, ultimately resulting in improved kidney function and patient outcomes in MM.