Digoxin Unit Conversion

Digoxin is the cardiac glycoside most frequently prescribed for the treatment of congestive heart failure and disorders characterized by abnormal heart rate. Digoxin functions by increasing the strength and velocity of myocardial contractions and slowing ventricular rate.

Digoxin toxicity continues to be a common clinical problem despite an increased understanding of the drug’s pharmacology. The incidence of digoxin toxicity has been reported as high as 35 %. Some overlap exists between therapeutic and toxic ranges; however, toxicity generally occurs at levels above 2.0 ng/mL (2.6 nmol/L). Based on actual new ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2008 a therapeutic concentration range for digoxin of 0.6-1.2 ng/mL (0.77-1.5 nmol/L) is recommended. Increased risk of mortality was observed for digoxin concentration of 1.2 ng/mL (1.5 nmol/L) and higher. Because the effects of digoxin toxicity are often severe and can be lethal, the significance of physicians becoming educated about the importance of serum digoxin monitoring and familiar with the signs of toxicity cannot be overstated. This is complicated by several factors: individuals vary in their sensitivity to digoxin; the drug has a low therapeutic to toxic ratio; and many of the signs of toxicity mimic the arrhythmias the drug is being used to treat.

The monitoring of serum or plasma digoxin levels should be used in conjunction with individual clinical symptoms and history, in providing physicians with information needed to ensure effective digoxin therapy while avoiding drug toxicity.

The usual therapeutic range for digoxin is 0.9-2.0 ng/mL (1.2-2.6 nmol/L). Concentrations above 2.0 ng/mL (2.6 nmol/L) are generally considered toxic.

Some overlap of toxic and nontoxic values has been reported. Based on actual new ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2008 a therapeutic concentration range for digoxin of 0.6-1.2 ng/mL (0.77-1.5 nmol/L) is recommended. Increased risk of mortality was observed for digoxin concentration of 1.2 ng/mL (1.5 nmol/L) and higher. Therefore, these values are provided only as a guide.