Beta-Blockers

Question 1

What are the 3 common classifications of beta-blockers?

Answer 1

Cardioselective (B1)
Nonselective (B1 and B2)
Alpha and beta

Question 2

What the names of some of the classic “beta adrenergic antagonists” (beta-blockers)?

Answer 2

Atenolol (Tenormin)
Bisoprolol (Zebeta)
Metoprolol (Lopressor)
Metoprolol Extended-Release (Toprol XL)
Carvedilol (Coreg)
Labetolol (Trandate)
Propranolol (Inderal)

Question 3

What suffix is associated with beta-blockers?

Answer 3

-olol

Question 4

What are the names of some of the common cardioselective (B1) beta-blockers?

Answer 4

Atenolol
Bisoprolol
Metoprolol

Question 5

What are the names of some of the common nonselective (B1 and B2) beta-blockers?

Answer 5

Carvedilol
Labetolol
Propranolol

Question 6

What are the names of some of the common alpha and beta beta-blockers?

Answer 6

Carvedilol

Labetolol

Question 7

What is the site of action for B1 beta-blockers?

Answer 7

Heart (1 heart)

Question 8

What is the site of action for B2 beta-blockers?

Answer 8

Lungs (2 lungs)

Question 9

What is the site of action for alpha and beta beta-blockers?

Answer 9

Peripheral –> arterioles

Question 10

MOA

Answer 10

Bind to beta-adrenoreceptors and block the binding of NE and E to them (block the beta receptors from receiving the sympathetic input from the NTs), which decr. HR, BP, and heart contractility

Question 11

Do beta-blockers vasoconstrict or vasodilate in the periphery and what effect does this have on the heart?

Answer 11

Vasodilate the periphery ==> decreases heart’s workload bc it will need less O2

Question 12

What is the MOA for selective (B1) beta-blockers?

Answer 12

Have a stronger effect in the periphery by focusing on the heart, thereby decreasing SE’s for the lungs

Question 13

What is the MOA for nonselective (B1 and B2) beta-blockers?

Answer 13

Block the beta receptors on both the heart and the lungs to decrease sympathetic input/activity –> causes bronchoconstriction in the lungs (which can worsen if the Pt. has underlying lung problems)

Question 14

What effect do nonselective (B1 and B2) beta-blockers have on the lungs?

Answer 14

Bronchoconstrict

Question 15

What “normal effects” of beta adrenergic stimulation do B1 beta-blockers block?

Answer 15

Cardiac stimulation –> decrease cardiac stimulation

Increased contraction and HR –> decreased contraction and decreased HR

Question 16

What “normal effects” of beta adrenergic stimulation do B2 beta-blockers block?

Answer 16

Lung stimulation (bronchodilation) --> decrease lung stimulation (bronchoconstriction)
Peripheral vasculature (vasodilation) --> vasoconstrict the periphery
*nonselective act on B1 and B2, so the heart and the lungs*

Question 17

What are some common adverse reaction of cardioselective (B1) beta-blockers (Metoprolol)?

Answer 17

Bradycardia (resting HR in 60’s) –> decreased CO so Pt. may not be able to handle high levels of exercise
Decreased exercise tolerance
Cold extremities
Depression

Question 18

What are some common adverse reactions of nonselective (B1 and B2) beta-blockers (Propranolol; Carvedilol)?

Answer 18

Bradycardia
Decreased exercise tolerance
Cold extremities
Depression
Blocks sx of hypoglycemia
Increased risk of hypoglycemia
Bronchospasm

Question 19

Which type of beta-blockers block the sx of hypoglycemia?

Answer 19

Nonselective (B1 and B2) (Propranolol; Carvedilol)

Question 20

A Pt. on a nonselective (B1 and B2) beta-blocker (Propranolol; Carvedilol) with DM has to worry about what, especially during exercise?

Answer 20

Blocked sx of hypoglycemia –> may not exhibit normal s/sx of diaphoresis, tremors, dizziness, etc.

Question 21

Describe the effect of max CO and beta-blockers on exercise tolerance.

Answer 21

Beta-blockers in theory limit exercise tolerance because of a decreased CO, so the Pt. may reach their max CO sooner, but if they are not working @ those high levels they may actually have an increased exercise tolerance @ low levels because the beta-blockers may decrease their chest pain when exercising, allowing them to tolerate the exercise better and exercise for longer at low- to moderate-intensity levels

Question 22

What are the exercise implications associated with beta-blockers?

Answer 22

Decreased VO2max and submax (if working @ those levels)
Enable individuals to have a greater ability to exercise before reaching ischemic threshold
Altered HR response to exercise –> MUST have exercise test with the Pt. to know their HR response; must allow adequate warm-up time to get the HR into the training zone

Question 23

Describe the HR response to exercise of a Pt. on a beta-blocker.

Answer 23

HR response to exercise is blunted in terms of a linear increase in response to incremental exercise (HR does not increase to the same maximal point bc RHR is in the 60’s and has a slower increase with activity, so the warm-up is very important)

Question 24

Can HR equations be used for a Pt. on a beta-blocker?

Answer 24

NO. Because the HR response is different, the slope of the line is different, so can not approximate –> use RPE scale (Borg - 6-20) or BB specific HR equations (can also o Karvonen max HR - 30bpm)