Digoxin is a steroid glycoside prepared from the dried leaves of the foxglove, and is used in small doses as a cardiac stimulantto improve the strength and efficiency of the heart, or to control the rate and rhythm of the heartbeat. Digoxin stimulates the heart muscle that leads to better blood circulation. Digoxin is also used for treating adults with mild to moderate congestive heart failure, atrial fibrillation, an abnormal heart rhythm, and children for increasing myocardial contractility.
Digoxin Mechanism of Action
All of Digoxin’s actions are responsible for stabilising and preserving the electrochemical gradients of sodium and potassium ions across plasma membranes through its effects on Na-K ATPase. The sodium-potassium pump, or K-pump, involves energy-dependent pumping of potassium, or the active transport of the potassium ion, across a biologic membrane. This K-pump is responsible for maintaining the intracellular environment throughout the body by moving potassium ions into cells and sodium ions out by inhibiting Na-K ATPase. Digoxin mechanism of action includes:
- In the myocardium and conduction system, Digoxin causes an increased availability of intracellular calcium, along with increased automaticity, increased inotropy, and a reduction in conduction velocity.
- Digoxin consequently affects the sinoatrial and atrioventricular nodes, while indirectly causingparasympathetic stimulation of the autonomic nervous system.
- Digoxinrenders blood vessels more sensitive to exogenous or endogenous catecholamines by reducing the catecholamine reuptake at nerve terminals.
- Digoxin consequently increases carotid bulb nerve activity, and improves sympathetic withdrawal for any given augmentation in mean arterial pressure, whileincreasing baroreceptor sensitization.
- At higher concentrations, Digoxin increases in both cardiac and peripheral sympathetic nerves, and sympathetic outflow from the central nervous system.
- At higher concentrations, Digoxinconsequently affects serum potassium levels, while allowing for a progressive efflux of intracellular potassium.
The cardiological consequences of these indirect and direct effects are a slowing of the heart rate, decreased conduction velocity through the AV node, an increase in the force and velocity of myocardial systolic contraction or positive inotropic action, and a decrease in the degree of activation of the sympathetic nervous system, renin-angiotensin system and a neurohormonal deactivating effect.
How to Take Digoxin Safely
With knowledge to Digoxin mechanism of action, it is also important to understand the proper use of the medication to get best result.
Before you take Digoxin, tell your health care professional if you have ever had any allergic reactions to this or any other medicines. Also let the doctor know if you’re planning on having a baby or you’re pregnant with a baby as whether the medicine will affect the unborn baby is not known.
Make sure your physician is aware of any health conditions such as:
- Any serious heart condition such as AV block, unless a pacemaker is used, or sinus node dysfunction (Sinus bardycardia)
- Any recent history of cardiac arrest
- Rapid heart rates, such as supra ventricular tachycardia, Wolff-Parkinson-White Syndrome, or atrial fibrillation.
- If you have a thyroid disorder
- If your blood work indicates low levels of potassium, calcium, or magnesium that result in an electrolyte imbalance
- If you have recently been sick, or are malnourished resulting from vomiting or diarrhea
- If you have kidney disease
- If you use steroid medicine or take a diuretic (water pill)
- If you are breast-feeding a baby
How to Take
- Take Digoxin orally with or without food as directed by your health care provider. However, your body may not fully absorb this drug as well as it should if you consume foods that are fiber rich, or in conjunction with other medications. It is recommended that Digoxin be taken at least 2 hours before, or 2 hours after eating for best results.
- If you are taking certain medications such as psyllium, colestipol, or cholestyramine, you’ll want to wait about 2 hours after you have taken the Digoxin. Other medication like antacids, milk of magnesia, kaolin-pectin sulfasalazine, amino salicylic acid, or metoclopramide, will need to be taken as far apart from your Digoxin dose as possible.
- The dosage of this medication is based on your medical condition, body weight, age, laboratory tests, and how you respond to treatment. When using Digoxin in its liquid form, the correct dosage is critical, so carefully measure the dose using the dropper provided by the manufacturer, and do not use a household spoon.
- Digoxin is most beneficial when used regularly, and consult with your doctor before you stop using this medication as your condition may worsen.
Possible Side Effects of Digoxin
Through Digoxin mechanism of action, conditions may be managed. However, it may also cause some side effects, which includes:
- Headache, dizziness, loss of appetite, nausea, vomiting, and diarrhea may occur. If any of these effects persist or worsen, tell your health care provider or pharmacist promptly.
- Tell your physician immediately if any of these unlikely but serious side effects occur, vision changes such as blurred, yellow or green vision, mental/mood changes, weakness, or gynecomastia (enlarged breasts), in men.
- Although Digoxin is used to treat certain types of irregular heartbeat, it may sometimes cause other types of irregular heartbeats. Tell your health care provider immediately if you notice any unusual fast, slow, or irregular heartbeats.
- A very serious allergic reaction to Digoxin is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction including, itching or swelling of the face, tongue, or throat, trouble breathing, rash, or severe dizziness.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your health care provider or pharmacist.