How Cardioselective Beta Blockers Work

Older man taking medications at table
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Beta blockers are a commonly prescribed type of medicine used to treat high blood pressure as well as irregular heartbeat, angina, and symptoms of anxiety. Also called beta-adrenergic receptor antagonists, beta blockers generally consist of two different types depending on the specific beta receptors they target—beta-1 or beta-2. 

The main difference between these two types of beta-adrenergic recepteta-1 receptors is that beta-1 receptors are mostly found in heart tissues whereas beta-2 receptors are found in the body's smooth muscle tissue, including those connected to the airways and skeletal system.

Beta blockers that target beta-1 receptors are known as cardioselective beta blockers. 

How Cardioselective Beta Blockers Work

Beta blockers work by preventing the neurotransmitters norepinephrine and epinephrine from binding to beta receptors. When these neurotransmitters are blocked, the effects of epinephrine (adrenaline) are diminished, allowing the heart to relax and beat more slowly. This, in turn, reduces the amount of blood that the heart is required to pump and improves the heart's pumping mechanism.

These medications are used to treat heart and blood pressure problems because both the heart and blood vessels have very high numbers of beta receptors. Cardioselective beta blockers are able to tell the two apart. Through their mechanism of action, cardioselective beta blockers are able to slow down your heart rate, reduce your heart's electrical conduction speed, and decrease the strength of heart contractions.

Some common cardioselective beta blockers include:

  • Sectral (acebutolol)
  • Tenormin (atenolol)
  • Zebeta (bisoprolol)
  • Brevibloc (esmolol)
  • Lopressor (metoprolol)

Cardioselective Beta Blocker Side Effects

All medicines carry some risk of side effects. While side effects with beta blockers are fairly uncommon, they have been reported.

If you are taking a beta-blocker and experience any side effects, notify your doctor. Some reported side effects include:

  • cold hands and feet
  • swollen ankles
  • slow heartbeat
  • difficulty breathing
  • joint pain

If you are taking a cardioselective beta blocker because you have asthma or other airway diseases, report any breathing problems to your doctor and seek medical care immediately for any serious difficulties.

Only you and your doctor can decide on a proper medication for the treatment of high blood pressure. Be sure to notify your doctor if you are pregnant and to supply the names of any other medicines and/or supplements you are taking. Remember to include over-the-counter medicines, such as aspirin or Advil, as well as herbal/natural supplements on your list.

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