What is the net effect of epinephrine on plasma potassium?

What is the net effect of epinephrine on plasma potassium?

• A. Hypokalemia
• B. Hyperkalemia
• C. No change
• D. Initial hyperkalemia followed by hypokalemia

Answer: (A)

The main idea is that epinephrine drives potassium into cells, reducing what’s in the plasma. It does this mainly through beta-2 adrenergic stimulation, which increases the activity of the Na+/K+-ATPase pump on cell membranes. As potassium is pumped from the extracellular space into cells, plasma potassium levels fall, producing a hypokalemic state. This rapid intracellular shift is why beta-agonists are used to acutely lower high potassium. The other options don’t fit the typical immediate effect: hyperkalemia would require potassium moving out of cells, no change ignores the rapid shift, and the pattern of initial hyperkalemia followed by hypokalemia isn’t the standard acute response to epinephrine.

The main idea is that epinephrine drives potassium into cells, reducing what’s in the plasma. It does this mainly through beta-2 adrenergic stimulation, which increases the activity of the Na+/K+-ATPase pump on cell membranes. As potassium is pumped from the extracellular space into cells, plasma potassium levels fall, producing a hypokalemic state. This rapid intracellular shift is why beta-agonists are used to acutely lower high potassium. The other options don’t fit the typical immediate effect: hyperkalemia would require potassium moving out of cells, no change ignores the rapid shift, and the pattern of initial hyperkalemia followed by hypokalemia isn’t the standard acute response to epinephrine.