Beta Adrenergic Blockers: Definition & Side Effects

Instructor: Adrianne Baron

Adrianne has a master's degree in cancer biology and has taught high school and college biology.

We are going to get a better understanding of what beta blockers are and the other names for this group of drugs. The side effects that occur with this group of drugs will also be covered in this lesson.

Beta Adrenergic Blockers

What do you think about when you hear the word 'block'? If you are like some sports enthusiasts, then you may immediately think about the last time your favorite basketball player had the game on the line with a few seconds for one last shot. He went up to make it and then the defender blocked the shot. What happened? The answer is nothing. The basketball didn't go into the hoop, so the team didn't get any more points and the game ended with your team losing.

Something fairly similar can happen in the body. There is a cascade of events that occurs in the body when the hormone adrenaline gets into the receptors on the organs and blood vessels in the body. The heart begins to beat faster and stronger, the other muscles in the body contract more and the walls of the blood vessels also contract. So how is this similar to the blocking of the basketball?

Beta blockers prevent the actions of adrenaline
Picture of beta blocker pack

Well, there are certain drugs called beta adrenergic blockers that block adrenaline from getting into the receptors we just mentioned. They literally get in the way of the receptor just like the defender gets in the way of the basket. Blocking that cascade of events means that the heart will not have to work hard, the muscles won't tighten up, and the blood vessels will remain relaxed. This allows the heart to need less oxygen and the blood pressure to decrease which is helpful in treatment following a heart attack.

Beta adrenergic blockers are also used to treat chest pain known as angina, high blood pressure, congestive heart failure, heart arrhythmias and may be helpful in managing migraine headaches and glaucoma. Beta adrenergic blockers are also referred to as:

  • beta blockers
  • beta adrenergic blocking agents
  • beta adrenergic antagonists
  • beta antagonists

Side Effects

With all the great things that beta adrenergic blockers can do, there are also some other things that they may cause to happen in your body that are less desirable. Considering some of the awful side effects that we have all heard during commercial ads, the ones associated with beta antagonists aren't that bad.

The most unpleasant and, actually rather rare side effects, are difficulty sleeping, trouble breathing or shortness of breath, and depression. One other thing that could happen, but doesn't happen often and isn't severe, is a change in certain cholesterol levels. The ones most often affected are high density cholesterol, often called the 'good cholesterol' and triglycerides. There may be a subtle change to a lower good cholesterol level and higher triglyceride level.

The most commonly reported side effects of beta adrenergic blockers are gaining weight, being excessive tired for no apparent reason, weakness, dizziness, and cold extremities.

Beta blockers can cause GI tract problems
Drawing of a person with stomach upset

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