What is Digoxin (Lanoxin) (TDM)?

Also Known As: Serum Digoxin Level

Formal Name: Digoxin serum

Digoxin is a drug used to treat heart failure and abnormal heart rhythms. Heart failure, including congestive heart failure (CHF), causes the heart to become less effective at circulating blood. As a result, blood backs up into the legs, hands, feet, lungs, and liver, causing swelling, shortness of breath, and fatigue. This test measures the amount of digoxin in the blood.

Digoxin is prescribed to relieve some symptoms of heart failure. It strengthens the contractions of the heart and helps it to pump blood more efficiently. Digoxin also helps control the heart rate and abnormal heart rhythms known as arrhythmias. It will not cure heart failure or arrhythmias, which are long-term (chronic) conditions but can help to manage the symptoms along with diet, exercise, and other medications.

Digoxin levels must be monitored because the drug has a narrow safety range. If the level in the blood is too low, symptoms may recur. If the level is too high, toxicity may occur. Digoxin dosage may be adjusted based on the levels measured.

How is the test used?

A digoxin test is used to monitor the drug level in the blood. The dose of digoxin prescribed may be adjusted depending on the level measured. Your healthcare practitioner may order one or more digoxin tests when you begin treatment to determine if the initial dosage is within therapeutic range and then order it at regular intervals to ensure that the therapeutic level is maintained. A digoxin test may also be used to determine if symptoms are due to an insufficient amount of the drug or to digoxin toxicity.