What Is Atenolol? - Uses & Side Effects

Instructor: Rachel Torrens
Atenolol is an old-school, beta blocker medication that is still in use today. Discover the most useful applications and potential side effects of atenolol through this lesson.

What Is Atenolol?

You're watching a scary movie. The heroine is walking towards the closed door, flashlight in hand. You scream vainly at the television, 'Don't do it!' You feel your own heart beat faster; your palms become sweaty. It's difficult to breathe. Other than Hollywood's spooky special effects, what is causing these physical symptoms to occur in your body? Adrenaline!

Adrenaline, also known as epinephrine, is coursing through your body in response to a supposed threat. There is a certain class of medication called beta-blockers, also known as beta-adrenergic blocking agents. These medications work by blocking epinephrine from binding, thereby preventing the very symptoms you experienced when watching the horror movie. Atenolol (trade name: Tenormin) is a beta-blocker medication.

Beta-blockers bind to the cardiac cell receptor site blocking adrenaline, also known as epinephrine, from activating the heart muscle.
Beta-blockers bind to the cardiac cell receptor site blocking adrenaline, also known as epinephrine, from activating the heart muscle.

Uses of Atenolol

Atenolol is used to treat several conditions in which the cardiovascular system needs to be told, 'Relax! It is okay, take a load off.' So, when exactly would you want to slow a heartbeat? Well, let's think about it. A heart that is beating very fast causes blood to be shot out of the heart into the cardiovascular system at very high speed, leading to high blood pressure. Just like when you turn a faucet. If you crank it all the way open, the water comes shooting out at very high pressure. If you were to turn it, say halfway, the water comes out at a more manageable speed. Therefore, atenolol is used in patients who have high blood pressure (hypertension). It tells the heart to beat more slowly, resulting in a more manageable and healthier blood pressure.

Atenolol decreases the work load of the heart by decreasing heart rate and lowering blood pressure.

Likewise, atenolol is used to decrease the workload of the heart in instances of heart attacks, chest pain, or heart failure. In these conditions, part of the heart muscle has stopped working properly, so the heart is being stressed by how much work it has to do. Atenolol blocks the 'Work faster! Work harder!' message from epinephrine, allowing the heart to work (beat) slower.

Lastly, atenolol can be used to treat migraines. Strange. How are migraines related to the cardiovascular system? Scientists believe that vasoconstriction, or the tightening of blood vessels by epinephrine, contributes to migraines occurring.

Have you ever washed your car? Everything is going smoothly, but now, you want to get a bird dropping off your car. You hold the water over it, but the stubborn dropping will not budge. So, you place your thumb over part of the opening of the hose, since decreasing the size of the hose increases the pressure. Instantly, the offending bird poo is removed. Atenolol takes the thumb away, so to speak, allowing the blood vessel to relax and become larger in size, or vasodilate. This allows increased blood flow to the brain, decreasing the occurrence and intensity of migraines.

Atenolol causes the blood vessels to widen and relax, a process known as vasodilation. This decreases blood pressure.
Vasodilation is the widening of the blood vessel.

Side Effects of Atenolol

Everything you ingest into your body has side effects, from the toothpaste on your toothbrush, to the cheeseburger you had for lunch, to your prescription medication. All have side effects; some intended, some not. Atenolol is considered an older generation beta-blocker, meaning side effects are more notable than in newer generation beta-blockers.

The following symptoms are more common, and do not necessarily require medical attention:

  • Dizziness or lightheadedness - especially following position change
  • Fatigue
  • Nausea or diarrhea
  • Blurred vision
  • Cold hands or feet
  • Mild depression - feeling down, lack of appetite, trouble concentrating, decreased sex drive
  • Mild weight gain - an average of four pounds (two kilograms) is noted

However, if any of the symptoms are persistent or unusually severe, then the medication dosage may need to be changed or a different medication may be needed all together.

In contrast, the list of following side effects warrants immediate evaluation by a health care professional:

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