Digoxin is a drug used to help control certain heart rhythm disorders and heart failure (weak heart). Digoxin enhances the heart’s pumping action, slows down the frequency of heart beats, and reduces shortness of breath and fatigue. Several conditions can affect blood levels and the efficacy of the prescribed digoxin dose (variation in intestinal absorption, kidney disease, combination with other drugs or natural products, etc.). The digoxin test measures blood levels of the drug at least 6 hours after the last dose (unless otherwise specified by the physician), and results are expressed in nanomoles of digoxin per litre of blood (nmol/L).
Most individuals respond with minimal side effects to a digoxin level between 1.0 and 2.5 nmol/L 6 hours or more after the last dose. In some individuals, this therapeutic window will not adequately control heart problems, while others will experience excessive side effects even if the level remains within the window. Results above 3.0 nmol/L, at least 6 hours after the last dose, are hazardous to health. The most common side effects of inappropriate digoxin levels are nausea, vomiting and diarrhea, abnormal behaviour, exaggerated drowsiness and dizziness, fainting, loss of appetite, intense headaches, etc.