Beta Blockers

Question 1

What do they do?

Answer 1

• Block beta receptors
• norepinephrine and epinephrine can’t bind to beta receptors
• therefore, we won’t elicit a sympathetic nervous system response

Question 2

What happens during a normal SNS response?

Answer 2

• Increased HR and BP
• Increased strength of heart contractions
• Bronchodilation
• Increase blood glucose via glycogenolisis

Question 3

Where are beta 1 receptors found?

Answer 3

• Heart
• Kidneys - juxtaglomerolar cells (release renin)

Question 4

Where are beta 2 receptors found?

Answer 4

• Lungs
• GI
• Vascular smooth muscle
• Skeletal muscle
• Ciliary body of eye

Question 5

What do selective BB target?

Answer 5

beta 1
(cardioselective)

Question 6

What do non-selective BB target?

Answer 6

beta 1&2

Question 7

3 examples of selective BB

Answer 7

atenolol
esmolol
metoprolol

Question 8

3 examples of non-selective BB

Answer 8

propanalol, sotalol, timalol

Question 9

How do BB slow HR?

Answer 9

BB effect the cardiac nodal tissue (contain BR) which controls the conduction of the heart. BB slow this conduction.

• monitor for AV blocks like 2 or 3 degree and severe bradycardia
• they can mask tachycardia in hypoglycemic episodes in diabetics

Question 10

How do BB decrease the strength of contractions? What should I look out for?

Answer 10

BP are in cardiac myocytes which control the contraction strength of the heart. BB make the contraction weaker which eases the workload on the heart and decreases the myocardiums oxygen consumption

• watch for development or worsening of HF, don’t give to patients with uncompensated HF or cardiogenic shock

Question 11

How do BB lower BP? What should I look out for?

Answer 11

BR are in the juxtaglomerular cells of the kidneys. BB prevent angiotensin II from being created in the RAAS because it inhibits the release of renin.

Angiotensin II normally causes vasoconstriction but there will be vasodilation instead, and the influence of aldosterone will be decreased, decreasing blood volume so therefore blood pressure.

• watch for hypotension

Question 12

How do BB decrease intraocular pressure?

Answer 12

The ciliary body of the eye has beta 2 receptors. Ciliary body is responsible for the production of aqueous humor. In pt’s with glaucoma, the high eye pressure is due to a high amount of aqueous humor in collecting in the eye. Non-selective beta blockers decrease the production of aqueous humor.

Question 13

How do BB cause bronchoconstriction?

Answer 13

Non-selective affect beta 2 receptors on the bronchioles of the lungs.

• do not give these medications to pts with asthma or COPD

Question 14

What are BB used for?

Answer 14

HTN, stable angina, dysrhythmias, HF, glaucoma, migraines, tremors, anxiety