Cardiovascular Drugs and Medications Q 45

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The therapeutic drug level for digoxin is:

  

     A. 0.1-2.0 ng/mg

     B. 1.0-2.0 ng/mg

     C. 0.1-0.5 ng/mg

     D. 0.5-2.0 ng/mg

    

    

Correct Answer: D. 0.5-2.0 ng/mg

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This is the correct therapeutic range for digoxin. Every nurse should know this information. The rate of toxicity increases as serum digoxin concentration reaches over 2.0 ng/ml. However, toxicity can also occur at lower levels, especially in the setting of other risk factors such as low body weight, advanced age, decreased renal function, and hypokalemia.

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Option A: Digoxin toxicity is clinically relevant as it can lead to fatal cardiac arrhythmias. The estimated frequency is at about 0.8 to 4% of patients on steady digoxin therapy.

Option B: Symptoms may be mild and include nausea, vomiting, and anorexia. Visual side effects might include color changes, also known as xanthopsia. But yellow or green-tinted vision is usually associated with digoxin toxicity. Patients may also highlight blurry vision or photopsia.

Option C: At toxic levels, digoxin is proarrhythmic. An impaired ventricle is more prone to ventricular tachyarrhythmias and ectopy. Abnormally high levels of digoxin stimulate atrial activation, thus atrial tachycardias, which, in a patient on digoxin, is highly suggestive of toxicity. These atrial tachycardias are persistent and resolve with a decrease in serum digoxin levels.

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