The effect of post-transplant spironolactone on daily potassium requirements in patients undergoing autologous stem cell transplantation
Excessive potassium (K+) loss is frequently seen post-transplant following platinum containing high-dose chemotherapy (HDC) regimens such as STAMP-I (cyclophosphamide + carmustine + cisplatin), STAMP-V (cyclophosphamide + thiotepa + carboplatin), ICE (ifosfamide + carboplatin + etoposide) and TMCb (thiotepa + melphalan + carboplatin). Nephrotoxic antibiotics which are commonly used in the post-transplant period may also cause hypokalemia. In general, the etiology of posttransplant hypokalemia is multi-factorial. Manifestations of hypokalemia seldom occur unless the plasma K+ is < 3 mEq/l. Profound K+ depletion is associated with an increased risk of cardiac arrhythmias and also rhabdomyolysis. Smooth-muscle function might also be affected and might manifest as paralytic ileus. The main reasons for profound hypokalemia after HDC are renal and gastrointestinal K+ loss due to nephrotoxicity from platinum or antibiotics and diarrhea associated with gastro-intestinal (GI) mucositis, due to alkylating agents such as thiotepa, melphalan and cyclophosphamide. Therefore, close followup of K+ levels is crucial for the first 2–3 weeks after transplantation. Daily K+ requirements in this setting may reach as much as 150–200 mEq/l/day. Whole day K+ replacement