Signs of digoxin toxicity can be subtle. Left unchecked, they can become severe and even life threatening. Digitalis, another name for digoxin, is derived from the foxglove plant. It is used today to treat congestive heart failure and atrial fibrillation. The medication slows the heart rate. It is known as a positive inotropic drug, meaning it increases contractility of the heart muscle. Digoxin helps the heart beat with more force. It is important to know signs of digoxin toxicity and how it can develop to prevent complications of medical therapy.
Visual Changes
Patients with signs of digoxin toxicity can have visual changes that make objects appear yellow or green. Blurred vision and double vision can also occur. The appearance of a halo around objects and images could indicate higher levels of digoxin. Sensitivity to light, also known as photophobia, can develop. Other visual changes include blind spots and seeing bright spots.
Gastrointestinal Effects
Nausea, vomiting and diarrhea are associated with digoxin toxicity. Patients who take the heart medication and develop symptoms of loss of appetite or other gastrointestinal symptoms should have a blood test to measure digoxin levels in the bloodstream.
Effects on the Heart
Patients with an intolerance to or who overdose on digoxin can develop sudden congestive heart failure. Symptoms of swelling in the extremities and abdomen, shortness of breath and fatigue can indicate heart failure from digoxin toxicity. The heart rate can become too slow, too fast or irregular. Fainting can occur from the heart rate becoming too rapid or too slow.
Other Physical Signs
Confusion or other mental status changes could indicate digoxin toxicity. Muscle weakness, headache and fatigue are also possible signs of digitalis toxicity or intolerance.
