Warnings and Precautions
Patients with significant sinus or AV block should not be given digoxin without first having a permanent pacemaker implanted. Digoxin should be used with caution with other agents that can depress sinus or AV nodal function (e.g., beta-blockers, nondihydropyridine CCBs). Digoxin also has numerous other drug interactions, which are outlined in Table 2. Clinicians should be aware of such interactions and monitor for digoxin toxicity, as well as check levels frequently.
If administered with careful attention to dosage and factors that may alter the drug's metabolism, digoxin is well tolerated by most patients with HF. AEs occur mainly when digoxin is administered in higher dosages, especially in the elderly, and it should be noted that larger dosages have not been found clinically beneficial.
The major AEs of digoxin (Table 3) include cardiac arrhythmias (ectopic and heart block), gastrointestinal symptoms (nausea, vomiting, anorexia), and neurologic complaints (visual disturbances, disorientation, confusion). Although overt digoxin toxicity occurs when serum levels are >2 ng/mL, toxicity may occur with lower digoxin levels, especially if electrolyte abnormalities such as hypokalemia and hypomagnesemia coexist.