How should electrolytes be monitored when starting MRA therapy?

• A. Check lipids weekly.
• B. No labs needed.
• C. Check potassium and creatinine within 3-7 days after initiation or uptitration; monitor for hyperkalemia.
• D. Check sodium only.

Answer: (D)

Starting an MRA can affect potassium handling and kidney function. Aldosterone antagonism reduces potassium excretion in the distal nephron, so serum potassium can rise (hyperkalemia) and kidney function can change, especially in patients with CKD, diabetes, or those taking other meds like ACE inhibitors or ARBs. Because of this risk, labs should be obtained within a short window after starting or increasing the dose—typically within 3 to 7 days—to check potassium and creatinine (or eGFR). Sodium levels aren’t the main concern with MRAs, and lipids aren’t the focus of this adjustment, so monitoring potassium and kidney function is the key step. After the initial check, continue regular monitoring as the dose is titrated and over the subsequent weeks and months.