Digoxin is the most widely used of the drugs derived from digitalis. It is used in the treatment of heart failure (reduced pumping efficiency of the heart) and certain types of arrhythmias (irregular heartbeat) such as atrial fibrillation (a rapid irregular beating of the heart muscle).


How digoxin works

Digoxin increases the force of heart muscle contractions, making the heart work more efficiently. It also slows down abnormally rapid impulses as they pass between the atria (upper chambers of the heart) to the ventricles (lower chambers of the heart), which allows the ventricles time to fill with blood and empty normally with each contraction.


Possible adverse effects of digoxin

If digoxin is to be effective, the dose must be just below that of toxic dose. The patient must therefore be given regular blood tests to ascertain the digoxin level. An excessive dose may cause loss of appetite, nausea, vomiting, and headache. Digoxin occasionally disrupts the normal heartbeat, causing heart block (an abnormally low rate of contraction).


Adverse effects are more likely if the potassium level in the body is low. Patients who are also taking diuretic drugs (and therefore are more likely to become deficient in potassium) are given regular blood tests to monitor potassium levels.


Because digoxin is removed from the body mainly in the urine, patients with kidney disease are usually given digitoxin as an alternative drug because of the risk of a build-up of toxic levels of digoxin.