A patient has a past history of heart failure and is controlled on digoxin (Lanoxin), $0.125 \mathrm{mg}$ daily. The nurse in the hospital and the home care nurse provided the patient with information about the adverse effects of digoxin, including digoxin toxicity. The patient has noticed that for the past 2 days, she has not had an appetite and she is nauseated. She makes an appointment with her health care provider, who orders a serum digoxin level and serum electrolyte panel. The results of the blood tests reveal a digoxin level of $10 \mathrm{ng} / \mathrm{mL}$ and a calcium level of $12 \mathrm{mg} / \mathrm{dL}$. The patient is administered digoxin immune fab (Digibind), $9.5 \mathrm{mg}$. Additional diagnostic studies are ordered, including a chest radiograph. The chest radiograph reveals a large mass in the right lower lobe of the lung.
- What is digoxin immune fab (Digibind)? How does digoxin immune fab (Digibind) work?
- How is the development of digoxin toxicity related to the increase in serum calcium levels?