Digitalis drugs, derived from the foxglove plant, are a class of medications used in some heart conditions. In the US, digoxin is the main digitalis drug. When the amount of digoxin in the blood becomes too high, toxic effects occur.
Digoxin is an effective medication that gives the heart muscle a stronger pumping action, and also helps control irregular heartbeats. However, compared to most medications, the leeway between an effective dose and one that causes side effects is very narrow.
Digoxin is a powerful medication that can cause death if it is taken inappropriately. The higher the dose, the greater the risk of toxic effects.
Digoxin toxicity can cause these symptoms: irregular heartbeats, or arrhythmias, that were not present beforechanges in color vision, such as a yellowish tint to the visionseeing halos around lightstirednessweaknessconfusiondizzinessabnormal dreams or nightmaresloss of appetitenausea and vomitingabdominal distress
Many medications interfere with the body's ability to get rid of digoxin and thereby increase the level of digoxin in the blood. These include antibiotics, other heart medications, and water pills (diuretics). Salt imbalances in the body can also increase the risk of digoxin toxicity.
The healthcare provider will often order a blood test to check salt and water balance and a therapeutic drug level to check the level of digoxin. A person taking digoxin should talk with his or her healthcare provider before starting or changing the dose of any prescription or over-the-counter medications.
Symptoms and findings of new arrhythmias make a healthcare provider suspect digoxin toxicity. A therapeutic drug level blood test can measure the level of digoxin and confirm the diagnosis. In severe cases, changes can be seen on an electrocardiogram (ECG), which records the electrical impulses of the heart.
In severe cases, digoxin toxicity can cause death.
There are no risks to others.
Mild digoxin toxicity can be treated by lowering the dose. Moderate toxicity may be treated with a short stay in the hospital. There, doctors will watch the person and stop the digoxin for a short time. Other heart medications may be needed to treat the arrhythmias caused by digoxin.
A severe case is a medical emergency. It may require the use of a pacemaker or powerful heart medications. An antidote is available for severe poisoning. The antidote attaches to the digoxin and stops its toxicity. In all cases, salt imbalances, especially low potassium levels, must be corrected.
Heart medications may cause allergic reactions and new arrhythmias. The antidote may also cause allergic reactions.
After recovery, the person is usually able to return to regular activities.
Close monitoring of salt balance and digoxin blood levels are needed. This helps prevent a recurrence of digoxin toxicity.
The Pharmacologic Basis of Therapeutics, 1995, Goodman and Gilman et al.