Digoxin, a prescription medication known by the brand names Lanoxin or Digitek, treats heart failure and dysrhythmias. Because many factors can cause digoxin to accumulate to toxic levels, patients taking this medication need regular check-ups to monitor their condition.
Heart Failure
In heart failure--also called congestive heart failure, or CHF--the heart's pumping ability is too weak to keep blood circulating effectively through the body. This results in backups (or congestion) of fluid, most often in the lungs and the legs. These backups cause two significant problems: difficulty breathing and swelling of the legs. Heart failure treatment tries to increase the pumping ability of the heart and reduce the amount of fluid to be pumped. Although digoxin was once the only medication for heart failure, in current medical practice doctors prescribe digoxin only after starting patients on three other medications: a diuretic (water pills), an ACE inhibitor (such as lisinopril) and a beta blocker (such as metoprolol). For heart failure not improved by this combination, doctors add digoxin to a patient's medications. Although medication can treat the symptoms of heart failure, the condition has no cure.
A Stronger Pump
Digoxin strengthens the contraction--or squeezing--of the heart and slows the heart rate. Stronger, slower contractions make for more effective pumping. This improved pumping ability increases the amount of blood squeezed out of the heart and into the arteries with each heartbeat. As more blood is pushed out, less blood backs up in the veins leading to the heart. As the backup in the circulatory system is reduced, breathing improves and swelling goes down.
Heart Rate and Rhythm
The heart's electrical activity controls the speed and rhythm of the heartbeat. Abnormal heart rhythms (called dysrhythmias or arrhythmias) arise from problems in the heart's electrical impulses. In a healthy heart, electrical impulses fire and travel through the heart in a regular rhythm at a controlled rate. When these impulses start in the wrong part of the heart, when they fire too fast, or when both occur, heart rhythms that are dangerous--or even fatal--can result.
Controlling Electrical Activity
Digoxin plays a role in controlling three dysrhythmias: supraventricular tachycardia (SVT), atrial fibrillation (a-fib) and atrial flutter (a-flutter). In SVT, the heart beats so fast, it can't pump properly and, therefore, blood can't circulate properly. Some people have short bursts of SVT without any symptoms, but prolonged SVT is an emergency. Doctors prescribe digoxin to stop SVT because digoxin slows the heartbeat. After SVT stops, the doctor may prescribe digoxin on a daily basis to prevent its return. With a-fib or a-flutter, too many electric impulses fire in the wrong part of the atria (the upper chambers of the heart) so that the heart beats too fast and the atria quiver or flutter instead of squeezing. Digoxin won't slow the beating of the atria, but it does stop some of the electrical impulses from traveling to the ventricles (the lower chambers of the heart) so they beat at a normal rate. When the ventricular rate is controlled, the heart can pump blood more effectively. Some patients with chronic a-fib or a-flutter may need prescriptions for digoxin.
References
- Medical-Surgical Nursing: Critical Thinking for Collaborative Care: Fifth Edition, Donna D. Ignatavicius, MS, RN,C and M. Linda Workman, PhD, RN, FAAN.; 2006
- Pharmacology for Nursing Care, Richard A. Lehne, PhD.; 2006
- Mayo Clinic: Digoxin
- MedlinePlus: Digoxin Oral
