Beta-Blockers Flashcards
What are the 3 common classifications of beta-blockers?
Cardioselective (B1)
Nonselective (B1 and B2)
Alpha and beta
What the names of some of the classic “beta adrenergic antagonists” (beta-blockers)?
Atenolol (Tenormin) Bisoprolol (Zebeta) Metoprolol (Lopressor) Metoprolol Extended-Release (Toprol XL) Carvedilol (Coreg) Labetolol (Trandate) Propranolol (Inderal)
What suffix is associated with beta-blockers?
-olol
What are the names of some of the common cardioselective (B1) beta-blockers?
Atenolol
Bisoprolol
Metoprolol
What are the names of some of the common nonselective (B1 and B2) beta-blockers?
Carvedilol
Labetolol
Propranolol
What are the names of some of the common alpha and beta beta-blockers?
Carvedilol
Labetolol
What is the site of action for B1 beta-blockers?
Heart (1 heart)
What is the site of action for B2 beta-blockers?
Lungs (2 lungs)
What is the site of action for alpha and beta beta-blockers?
Peripheral –> arterioles
MOA
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
Do beta-blockers vasoconstrict or vasodilate in the periphery and what effect does this have on the heart?
Vasodilate the periphery ==> decreases heart’s workload bc it will need less O2
What is the MOA for selective (B1) beta-blockers?
Have a stronger effect in the periphery by focusing on the heart, thereby decreasing SE’s for the lungs
What is the MOA for nonselective (B1 and B2) beta-blockers?
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)
What effect do nonselective (B1 and B2) beta-blockers have on the lungs?
Bronchoconstrict
What “normal effects” of beta adrenergic stimulation do B1 beta-blockers block?
Cardiac stimulation –> decrease cardiac stimulation
Increased contraction and HR –> decreased contraction and decreased HR
What “normal effects” of beta adrenergic stimulation do B2 beta-blockers block?
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*
What are some common adverse reaction of cardioselective (B1) beta-blockers (Metoprolol)?
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
What are some common adverse reactions of nonselective (B1 and B2) beta-blockers (Propranolol; Carvedilol)?
Bradycardia Decreased exercise tolerance Cold extremities Depression Blocks sx of hypoglycemia Increased risk of hypoglycemia Bronchospasm
Which type of beta-blockers block the sx of hypoglycemia?
Nonselective (B1 and B2) (Propranolol; Carvedilol)
A Pt. on a nonselective (B1 and B2) beta-blocker (Propranolol; Carvedilol) with DM has to worry about what, especially during exercise?
Blocked sx of hypoglycemia –> may not exhibit normal s/sx of diaphoresis, tremors, dizziness, etc.
Describe the effect of max CO and beta-blockers on exercise tolerance.
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
What are the exercise implications associated with beta-blockers?
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
Describe the HR response to exercise of a Pt. on a beta-blocker.
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)
Can HR equations be used for a Pt. on a beta-blocker?
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)
