Indications
Digoxin is used for the following indications:
- Heart failure (pumping weakness of the heart)
- Atrial flutter and flicker (due to the delay in excitation transfer)
Side effects
Digoxin has a narrow therapeutic range. This means that it is very easy to overdose, which leads to intoxication. This is because inhibition of the sodium–potassium pump must always be done in moderation, otherwise the entire cell stability is shaken. Symptoms of an overdose can be the following: The therapy of a digoxin intoxication consists of the administration of an infusion solution containing potassium (since an increased potassium concentration displaces the cardiac glycosides from the sodium-potassium ATPase and thus inhibits their effect), antiarrhythmic drugs (drugs that limit the cardiac arrhythmia that may be triggered), digitalis antibodies (which capture specifically free cardiac glycoside molecules and thus render them ineffective).
- At the heart: cardiac arrhythmia such as ventricular fibrillation, extrasystoles in the chamber muscles, AV block
- In the central nervous system: color vision disorders, fatigue, states of confusion
- In the gastrointestinal tract: nausea, vomiting
Interactions
Many factors and parallel administration of other drugs can influence the effect of digoxin, therefore a precise anamnesis (systematic questioning of the patient about previous illnesses, drug use, etc.) must be taken before prescription and administration. Factors that can cause interactions include Potassium concentration – hyperkalemia (increased potassium concentration) leads to reduced efficacy, hypokalemia (decreased potassium concentration), on the other hand, increases the effect and can therefore – when a normal dose is administered – lead to symptoms of poisoningKidney insufficiency – patients with kidney dysfunction should not be treated with digoxin, Digitoxin should be preferred here, as it is less excreted via the kidneysMedicines that activate or inhibit drug-degrading enzymes of the liver (induction or repression of CYP enzymes) These include some antibiotics, antiepileptics, St. John’s wort and antiarrhythmics.
