A type of medicine that strengthens the heart: Let's learn everything about Cardiac Glycosides in a simple way!

Someone in your family, perhaps your mother, father, or grandparents, is probably taking medication for a heart condition. Among such medications, there is a type of medication that has been used for a long time and that gives special strength to the heart. Today we are going to talk about a group of drugs called Cardiac Glycosides. Although the name is a bit confusing, the way these work and the facts we need to know are very important.

Simply put, what are these cardiac glycosides?

Cardiac glycosides are a group of medications that help people with certain heart conditions. They can come in the form of tablets, syrup, or capsules. Doctors usually prescribe these medications to be taken once a day, at the same time every day.

It is very surprising that this type of medicine was first discovered from a flowering plant called "Digitalis" or "foxglove." That is why some of the medicines in this group are named after that plant.

How does this medicine work inside the body?

There are some scientific facts to understand this, but I'll explain it to you very simply.

Think of the cells in our heart muscle as little pumps. Inside these cells are things called sodium and calcium. The balance of these is very important for the heart to beat properly.

1. Sodium control: When you take a cardiac glycoside drug, it somewhat controls the pumping of sodium out of the heart cells. To be precise, it stops that process for a while.

2. Increased calcium: When the amount of sodium inside the cells increases, the amount of calcium inside the cells automatically increases in response.

3. Strengthening of the heart rate: With each heartbeat, this excess calcium is released. This causes the heart muscle to contract more forcefully. This means that the amount of blood pumped into the body with each beat (which we call Stroke Volume in medicine) increases.

4. Increased overall performance: When the amount of blood pumped in one beat increases, the total amount of blood pumped by the heart (called cardiac output ) increases. This is a great relief for someone with conditions like heart failure.

In addition, these drugs do something else important. There is a special place where electrical signals that control the heartbeat travel, called the Atrioventricular (AV) node . These drugs can slow down the speed at which those signals travel. This reduces the heart rate. This is very beneficial for people with conditions that cause rapid heartbeats, such as atrial fibrillation .

What are the types of cardiac glycosides and which are the most commonly used?

There are several medications that belong to this class of drugs.

• Digoxin
• Digitalis
• Digitoxin

Of these, the one that you, I, and everyone else have heard of, and the one most commonly used in Sri Lanka and around the world, is Digoxin . Check to see if this name is on your prescription.

Who is prescribed these medications? Why aren't they the first choice?

Cardiac glycosides are generally prescribed for two main conditions.

1. Heart Failure: A condition in which the heart is unable to pump enough blood to the body.

2. Heartbeat irregularities (Arrhythmias): Especially for cases where the heart rate increases uncontrollably, such as Atrial Fibrillation.

But here is a very important point that we all need to know. Nowadays, Cardiac Glycosides are not the first-line treatment of doctors. 20-30 years ago, they were very widely used. But now, there are newer drugs that are safer, have fewer side effects, and are available.

A doctor will first try these types of medications:

• Beta-blockers
• ACE inhibitors
• Diuretics (medicines that reduce water in the body)
• ARBs

Only if these medications fail to control the disease or if the patient has other complications, will a doctor use Cardiac Glycosides, especially Digoxin, as a second or third step.

Are we also aware of the risks and side effects?

When talking about this medication, one thing to be aware of is the risk. There is a very small gap between the therapeutic dose and the toxic dose of this medication. This means that even if you take a little more than the recommended dose, you are still likely to experience side effects.

This is why your doctor will regularly check your blood (serum digoxin level) to see if the medication level in your body is at the correct level.

Please note: If your potassium levels are low, you are at higher risk of side effects from this medication. Therefore, your doctor will also check your potassium levels regularly.

When do you need to see a doctor immediately?

If you are taking a cardiac glycoside, especially Digoxin, you should contact your doctor immediately if you experience any of the following symptoms. If the symptoms are severe, go to the Emergency Department (ETU) of the nearest hospital.

How long does it take for the medicine to work?

After starting this medication, it may take several weeks, or even a month or two, before your symptoms begin to improve. So be patient and continue taking the medication as your doctor tells you.

Most importantly: Never stop taking this medication without consulting your doctor, just because you think you're feeling better. Also, don't take more than the prescribed dose. Always talk to your doctor about how the medication is affecting you.