Digoxin is converted to another substance in the body, glucuronic acid, in the liver. Digoxin plasma concentrations may rise in response to medications that block hepatic microsomal enzymes. Erythromycin, diltiazem, verapamil, quinidine, fluoxetine, and paroxetine are a few examples of such medications.
Digoxin and digitalis glycoside plasma concentrations may rise when the two medications are taken together. Therefore, it is advised that when these medications are used together, serum drug concentrations be closely monitored.
After oral administration, digoxin is quickly and completely absorbed from the GI tract, but peak plasma concentrations are delayed for about 6 hours. Food slows down absorption, but not to the same extent.
Digoxin is widely distributed throughout the body after oral administration, with a volume of distribution of about 4 L/kg. Digoxin is released into breast milk after crossing the placenta. Between 25% and 40% of plasma proteins are bound.
Excretion and Metabolism:
Digoxin is converted to glucuronic acid and excreted by the kidney after being metabolized in the liver. Digoxin typically has a half-life of 24 to 48 hours, but in people with kidney disease, it can last up to 72 hours or longer. Digoxin excretion is reduced in congestive heart failure patients.
Digoxin Indications and Use
Digoxin is prescribed for the management of associated ventricular arrhythmias and the treatment of mild to moderate congestive heart failure (CHF). Digoxin has a positive inotropic effect on myocardial contractility in CHF without increasing myocardial oxygen demand. The enhanced sodium-potassium ATPase activity in cardiac muscle cell membranes and the increased calcium uptake by the sarcoplasmic reticulum are primarily responsible for the favorable inotropic effect. The end result is a decrease in ventricular filling pressures and an increase in cardiac output.
Digoxin has been used alone or in combination with other medications to treat CHF, and it has been linked to improvements in symptoms, weight loss, and exercise tolerance. However, data from large clinical trials have not been able to show a benefit in terms of mortality.
Digoxin is also recommended for the treatment of flutter and atrial fibrillation. Digoxin reduces automaticity and conduction velocity while having little impact on refractoriness in both arrhythmias. As a result, both the heart rate and the risk of thromboembolic complications in atrial fibrillation decrease.
Digoxin is not recommended for use in people with known drug hypersensitivity, ventricular fibrillation, or ventricular tachycardia. Digoxin should not be used in patients who have severe bradycardia (40 bpm) unless an artificial pacemaker is present and working.
Digoxin's gastrointestinal side effects are most frequently associated with anorexia, nausea, vomiting, and diarrhea. These side effects are typically minor and go away as long as treatment is continued.
A serious or fatal cardiac arrhythmia may also be brought on by digoxin. Atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation are all arrhythmias connected to digoxin therapy. Additionally, digoxin may result in heart block, which may be dangerous or fatal.
Digoxin can also cause less frequent side effects like headaches, vertigo, blurred vision, confusion, depression, and hallucinations. When therapy is stopped, these side effects typically go away.
Senior patients may experience more severe side effects, such as heart block and cardiac arrhythmias.
Dosage and Administration
Tablet, elixir, and injectable forms of digoxin are all readily available. Digoxin is typically started at 0.125 mg per day. Every two to four weeks, the dose may be raised by 0.125 mg to achieve the desired clinical effect or to reduce side effects that are intolerable. The typical daily maintenance dose is between 0.25 and 0.5 mg.
Digoxin's typical starting dose for patients with atrial fibrillation or flutter is 0.25 mg per day. Every two to four weeks, the dose may be raised by 0.25 mg to achieve the desired clinical effect or to reduce side effects that are intolerable. The typical daily maintenance dose is between 0.5 and 1 mg.
Digoxin comes as a tablet, elixir, and injectable. Digoxin's standard starting dose is 0.125 mg per day. Until the desired clinical effect is obtained or the side effects become intolerable, the dose may be raised by 0.125 mg every two to four weeks. 0.25 to 0.5 mg per day is the typical maintenance dose.
Digoxin is typically started at 0.25 mg per day in patients with atrial fibrillation or flutter. Until the desired clinical effect is obtained or the side effects become intolerable, the dose may be raised by 0.25 mg every two to four weeks. 0.5 to 1 mg per day is the typical maintenance dose.
Digoxin has several therapeutic effects, including a decrease in heart rate and a lower risk of thromboembolic complications in atrial fibrillation.
Toxicity - Toxicity may present as heart block, cardiac arrhythmias, gastrointestinal distress, or visual disturbances. Digoxin plasma concentrations should be closely watched and kept within the therapeutic range. To find arrhythmias, electrocardiography should be performed frequently.
Digoxin tablets should be kept between 15 and 30 degrees Celsius (59 and 86 degrees Fahrenheit).
Digoxin elixir needs to be kept between 2 and 8 degrees Celsius (36 and 46 degrees Fahrenheit).
Digoxin injection needs to be kept between 15 C and 30 C (59 F and 86 F) of ambient temperature.