Final answer:
Hypokalemia and hypocalcemia can increase the risk of digoxin toxicity when taken with furosemide (Lasix).
Step-by-step explanation:
The correct answer is 4. Hypokalemia and hypocalcemia. When a patient receives furosemide (Lasix) and digoxin (Lanoxin) together, it can increase the risk of digoxin toxicity. Furosemide is a loop diuretic that can cause hypokalemia (low potassium levels) and hypocalcemia (low calcium levels). Both hypokalemia and hypocalcemia can increase the risk of digoxin toxicity, as digoxin works by affecting the movement of potassium and calcium in the heart.