Digoxin

A digoxin test is requested by your doctor to measure the amount of digoxin that is present in your blood. The dose of digoxin prescribed by your doctor may be adjusted depending on the result of your blood test. Your doctor may want to measure digoxin at regular intervals to ensure that an appropriate level is maintained, especially if your kidney function changes as the drug is excreted through the kidneys.

The test to measure digoxin is requested at the beginning of drug treatment to ensure correct dosage. Digoxin takes approximately one to two weeks to reach a steady level in the blood and in the heart. A test done at the right time will be a better indication of whether you are receiving the right amount of digoxin. Digoxin levels will then be measured at a frequency decided by your doctor to maintain the right dose, or if any changes occur in the type of tablet, the dose or other medicines taken at the same time. Changes in your health can also affect levels of digoxin and its ability to control your symptoms. Some physiological changes that may affect levels of digoxin in the blood are:

• kidney function
• thyroid problems
• cancer
• stomach or intestinal illness

Digoxin will not cure heart failure but will help to control it. Since digoxin is prescribed to treat patients with a long-term, chronic condition, it is usually monitored throughout the treatment.

Timing of the digoxin blood test is important. The sample should be collected at least 6-8 hours after you last took your digoxin. Very often, the blood sample will be collected just before the next dose is to be taken. Timing of the sample collection is important because if the sample is collected too soon after the drug is taken, the results of the test could be misleading and may appear to be toxic (very high) when this is not the case. This is because digoxin needs to distribute through the body after a dose has been taken, and specimens taken within the first six hours do not give enough time for this distribution to take place.

The appropriate (“target”) range for digoxin has been established over time as 0.5-2.0 µg/L for patients being treated for heart failure. Several newer studies suggest a narrower range, 0.5-1.0 µg/L, may be appropriate for some patients. The recommended range for patients with a/node/264 is 1.5-2.0 µg/L. Most patients find that their symptoms improve when their digoxin results are within this range.

It is important to note that each patient’s response to medicines is individual and other factors such as kidney function or other drugs taken at the same time may be important. If your symptoms have not improved or if you have side effects, tell your doctor immediately. He/she may need to change your dose to meet your individual needs.

If your result does not fall within the “target” range but you are not experiencing symptoms, continue to take your medication as prescribed until you consult with the doctor who requested the test. He/she will evaluate your case and decide if it is necessary to adjust your dose. If your dose needs to be adjusted, your doctor may request further digoxin tests to determine the resulting blood level.

Several prescribed and over-the-counter drugs can affect the level and effectiveness of digoxin in your system. Be sure to tell your doctor about all other medicines you may be taking.

Digoxin is mainly removed from your blood by the kidneys. Tell your doctor if you have, or have had, kidney problems. Your doctor may want to measure blood potassium levels since low levels of potassium can result in symptoms of toxicity.

If toxic levels are found, reducing the dose of digoxin or stopping the drug for a short time is sufficient to bring levels back to normal quickly. In severe cases where highly toxic levels of digoxin are measured, anti-digoxin antisera may be given to reverse the effects of the drug.

Digoxin is usually taken for your lifetime, although it may be stopped under close medical supervision in some cases.