Beta Blockers

Question 1

Where are the beta receptors found that beta blockers act on?

Answer 1

Block B1 - which is found in heart and is responsbile for tachycardia and increased contractility
B2 - blood vessels - dilation
B1 - kidney causes renin release
B2 - in lungs - bronchodilation

-so will decrease heart rate,a and also decrease renin, can also cause bronchoconstriciton - need to be careful of this

Question 2

How to beta receptors work?

Answer 2

• noradrenaline is released and …
• Are on post synaptic cells
• activation will activate adenylate cyclase, which result in increased contractility and heart rate

Question 3

What happens to beta receptors when have a beta blocker?

Answer 3

-get increased no. of beta receptors on cell membrane to try and overcome this

Question 4

Metoprolol

Answer 4

beta 1 blocker- hypertension, angina, heart failure

Question 5

Carvedilol

Answer 5

• beta blocker both 1 and 2,
• alpha blocker
• good for heart failure

Question 6

Labetalol

Answer 6

• beta 1 and 2 and alpha blocker
• very safe
• good for high BP in pregnancy

Question 7

Acute vs chornic heart failure

Answer 7

• acute - dont want to give beta blocker becasue can make emergenecy heart failure worse because this person is dependent on the sympathetic drive to maintain CO - will worsen condition - stabalise this patient with oxygen and diuretics then can introduce beta blocker after a week
• good for chronic - then can use beta blockers

Question 8

Effects of beta blockers

Answer 8

• asthma - can cause brochoconstriction
• hypotension, bradycardia
• fatigue
• drug withdrawl - get icnrease beta receptors so get slow decrease of this

Question 9

Beta blocker drug interactions

Answer 9

• Verapamil, diltiazem - all are inotropic drugs - so will give patient bradycardia if do this
• anti-diabetic lectures

Question 10

What are good drugs for angina?

Answer 10

• want to reduce heart rate and cardiac work

- metoprolol common in NZ

Question 11

What can be used for MI?

Answer 11

• after MI get a big sympathetic surge

- which can cause arrhythmias, ventricular ruputre and cardiac remodeeling

Question 12

Heart failure

Answer 12

• have ace inhibitors and beta blockers

- carvedilol, metoprolol, bisoprolol all equally effective

Question 13

Senario 1. angina, asthma, hypertenison

Answer 13

• use diltizem

- cannto use beta blocker due to asthma

Question 14

Senario 2 - SOB, pulmonary oedemea, hypxoic, fluic overload, chest crackles

Answer 14

acute heart failure

• Avoid beta blocker orrignialtly
• intiial treatment - diuretics, o2, nitrates, ace inhibitor, and after a weeks - can do beta blocker