Adverse Effects And Toxicology Practice Test

The key idea is how digoxin affects potassium handling in the body. Digoxin inhibits the Na+/K+ ATPase pump on cell membranes. When this pump is blocked, potassium tends to move out of cells into the extracellular space. In an acute overdose, this leads to a rise in serum potassium—hyperkalemia—which is a common and important finding and it also signals a potentially severe, life-threatening toxicity. This mechanism is why hyperkalemia is the classic electrolyte abnormality associated with acute digoxin toxicity. While low potassium can increase the risk of digoxin toxicity in other scenarios (because digoxin binds more readily when K+ is low), the immediate, characteristic electrolyte change seen with an acute overdose is elevated potassium. Hypercalcemia and hypomagnesemia aren’t the hallmark findings of acute digoxin toxicity.