Digoxin is characterized by which type of therapeutic range?

• A. Wide therapeutic window
• B. Not used for heart conditions
• C. Narrow therapeutic window
• D. Rapidly absorbed

Answer: (C)

The key idea is the safety margin between the therapeutic effect and toxicity. Digoxin has a narrow therapeutic window, meaning the dose that provides clinical benefit is close to the dose that can cause toxicity. This tight margin requires careful dosing and regular monitoring of blood levels, especially since renal function strongly influences clearance and electrolytes can modulate toxicity risk. Clinicians target appropriate levels carefully and watch for signs of toxicity such as GI upset, confusion or vision changes, or rhythm disturbances. The statements about rapid absorption or wide safety margins don’t describe the drug’s therapeutic range, and while digoxin is used for certain heart conditions, that use is not what defines its therapeutic range.