Digoxin
Digoxin is a cardiac glycoside that inhibits the sodium-potassium pump in heart muscle cells, which strengthens the force of contraction and slows conduction through the atrioventricular node. It is used to control the heart rate in certain arrhythmias, particularly atrial fibrillation, and to relieve symptoms in heart failure.
The gap between a working amount and a toxic one is narrow. It is kept apart from high-fibre food, which binds it and makes absorption erratic. Diuretics such as furosemide and indapamide lower potassium, and low potassium or magnesium makes the heart far more sensitive to digoxin; clarithromycin raises digoxin levels directly. Potassium, magnesium, creatinine and eGFR are checked periodically, since failing kidneys allow the drug to accumulate.
Nausea, loss of appetite, confusion, disturbed colour vision or yellow-green halos around lights, and a heartbeat that becomes very slow or irregular are signs of toxicity and mean seeing a doctor promptly.
Reference information, not medical advice. Discuss any change with your doctor.