Studying about digoxin
Tags: Drugs, Medicine, Digoxin, Medication, Pharmaceutical

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Digoxin, also known as Lanoxin, is the most common prescribed type of medicine called the cardiac glycoside. Cardiac glycosides are medication that is commonly extracted from a foxglove plants like the digitalis purpurea and digitalis lanata. Digoxin is used to control arrhythmias, atrial fibrillation, congestive heart failure and other heart problems, and it is usually taken along with other medicines. This can come in tablets, liquid, and also by injection.

How does digoxin work?

This slows down the heart rate, and makes it easier for the heart to pump blood throughout the body. Digoxin works by affecting sodium and potassium that is inside the heart cells. Cardiac glycoside like the digoxin involves in the sodium-potassium pump or the Na+K+ATPase enzyme, where it causes the sodium to build up inside the heart cells, and decreases the ability of the Na+Ca+ exchanger to push the Ca+ out of the cells causing it to accumulate in the sarcoplasmic reticulum. Cardiac glycosides increases force of the contraction of the heart.

Digoxin lessens strain in the heart, and helps it to maintain a normal, steady, strong, and a better working heartbeat. This type of cardiac glycoside is binding reversibly to a receptor site in the sodium-potassium pump in where it inhibits the function of exchanging Na+ and K+ across the cell membrane. Digoxin lessens the symptoms during rapid ventricular contractions by blocking the electrical conduction between the atria and the ventricles, while digoxin does its work, there could be a slowing down of contraction of the ventricles.

Indications

Congestive heart failure

Ventricular rate control in atrial fibrillation and atrial flutter

Reentry SVTs

Arrhythmias

Atrial tachycardia

Contraindications

Ventricular fibrillation

Ventricular tachycardia

Constrictive pericarditis

Digitalis toxicity

Hypersensitivity

Atrioventricular block

What are the possible side effects of digoxin?

Nausea

Vomiting

Diarrhea

Headache and dizziness

Skin rashes

Tiredness/ fatigue

Anxiety and hallucinations

Electrolyte imbalances

Increased blood level

Arrhythmias

Doses for digoxin

For tablets:

0.0625 mg, 0.125 mg, 0.1875 mg, and 0.25 mg

For liquid:

0.05 mg/mL

By injection:

0.1 — 0.25 mg/mL

Possible Risks and Hazards

1. Acute digoxin intoxication

It is more likely to occur in younger patients following an acute overdose, and is most likely to cause gastrointestinal symptoms.

Symptoms include anorexia, vomiting, nausea, visual changes (alteration in color vision), hyperkalemia, cardiac arrhythmia, asystole, ventricular tachycardia, second or third-degree AV block and dysrhythmias.

Treatment includes immunotherapy where it will reverse the effects of the digoxin, lidocaine in ventricular tachyarrhythmias, atropine/ pacemaker in bradyarrhythmia, and calcium gluconate, +/- sodium bicarbonate, +/- sodium polystyrene sulfonate in hyperkalemia.

2. Chronic digoxin intoxication

This frequently occurs in elderly patients resulting in decreased clearance of digoxin, commonly due to drug interactions or declining renal function.

Symptoms include nausea, malaise, electrolyte abnormalities, fatigue, lethargy, confusion, and hyperkalemia/ hypokalemia.

Treatments include digoxin immune Fab fragments.

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