beta-blocker

Question 1

uses of beta blockers

Answer 1

• hypertension
• angina
• heart failure
• arrhythmias (AF, atrial flutter, SVT)

Question 2

mechanism of action

Answer 2

• block post-synaptic β receptors → inhibiting sympathetic activity
• chronic β-blockage changes kinase activity associated w/ β-receptors
• post-synaptic membrane up-regulates β receptors

Question 3

receptor type and effect in the heart

Answer 3

B1

tachycardia, increased contractility, relaxation

Question 4

receptor type and effect in the kidneys

Answer 4

B1 and B2

causes renin release

Question 5

difference between water soluble and lipid soluble drugs

Answer 5

water soluble

• elimination by the kidneys
• e.g. atenolol, sotalol

lipid soluble

• elimination by the liver
• has a shorter half-life so given in slow release formula
• passes through BBB, may have central effects
• e.g. propranolol, metaprolol

Question 6

pharmacodynamics - CVS effect

Answer 6

BP lowering

• reduce CO (decrease HR, & cardiac work)
• negative chronotropic
• renin inhibition (B in juxtaglomerular)
• central of sympathetic drive
• reset baroreceptors to decrease sympathetic drive
• inotropic effects (acutely negative, chronically positive) e.g. beta-blockers good for chronic bad for acute

Question 7

pharmacodynamics - respiratory effect

Answer 7

• B2 receptor antagonism (bronchoconstriction)

- contraindicated in asthmatics

Question 8

adverse effects of Beta-blockers

Answer 8

• asthma exacerbation
• hypotension
• bradycardia
• fatigue, impotence, nightmares
• mask hypoglycaemia
• promote vasospasm

Question 9

drug interactions

Answer 9

verapamil = both have potent negative chronotropic effects

diltiazem = caution, but acceptable

other BP lowering drugs

Question 10

contraindications

Answer 10

acute HF (as B-blockers acutely reduce inotropy)

asthma

Question 11

beta blocker in angina

- mechanism and drug example

Answer 11

• decrease HR, cardiac work
• improve symptoms

e.g. metoprolol or atenolol

Question 12

beta blocker post MI

- mechanism

Answer 12

• decrease arrhythmias
• decrease ventricular rupture
• increased cardiac remodelling

Question 13

example of beta-blocker given in hypertension

Answer 13

• atenolol

- metoprolol

Question 14

beta blocker in HF

- mechanism and drug example

Answer 14

• decrease cardiac sympathetic tone
• up-regulation of B receptors
• improve baroreceptor function
• improve LV remodelling

e.g. carvedilol, metoprolol, bisoprolol