Anti-hypersensitive - b-blockers

Question 1

Of the list below, which drug is NOT one of the core B-blocker drug we need to be aware of?

1 - Doxazosin
2 - Bisoprolol
3 - Propranolol
4 - Carvedilol

Answer 1

1 - Doxazosin

• this is an alpha blocker

Question 2

B-blockers, such as Bisoprolol, Propranolol and Carvedilol all bind with which receptor located primarily on cardiac tissue?

1 - alpha 1
2 - beta 1
3 - beta 2
4 - beta 3

Answer 2

2 - beta 1

Question 3

B-blockers, such as Bisoprolol, Propranolol and Carvedilol primarily bind with beta 1 receptors located on cardiac tissue. Which of the GPCRs pathways does this activate?

1- Gq
2 - Gs
3 - Gi
4 - Gd

Answer 3

2 - Gs

• all B receptors use this pathway

Question 4

Once catecholamines bind with B receptors they initiate the GPCR Gs. Organised the labels below to show what happens intraceulluarly:

1 - pKA can then phosphorylate inside cell
2 - AC takes 2 phosphates and becomes cyclic adenosine monophosphate (cAMP)
3 - adenylate cyclase (AC) is activate
4 - cAMP activates protein kinase A (pKA)

Answer 4

1 - adenylate cyclase (AC) is activate
2 - AC takes 2 phosphates and becomes cyclic adenosine monophosphate (cAMP).
3 - cAMP activates protein kinase A (pKA)
4 - pKA can then phosphorylate inside cell

Question 5

What is the mechanism of action of B-blockers?

1 - selectively bind b1 receptors and compete with binding of noradrenaline and adrenaline
2 - non-selectively binds a1 and B1 receptors, inhibiting Acetylcholine binding
3 - selectively bind a-1 receptors and compete with binding of Acetylcholine
4 - non-selectively binds a1 and B1 receptors, inhibiting noradrenaline and adrenaline binding

Answer 5

1 - selectively bind a-1 receptors and compete with binding of noradrenaline and adrenaline

• this is a 2nd generation B-blocker so it is able to selectively bind at the post synapse
• reduces noradrenaline and adrenaline binding

Question 6

B1 adrenergic receptors typically increase heart rate and contractility in the heart. The use of B-blockers is indicated in ischaemic heart disease (IHD), by improving prognosis in angina and acute coronary syndrome. How do B-blockers improve prognosis in IHD?

1 - increase HR and reduce contractility
2 - reduces HR and increase contractility
3 - increase HR and contractility
4 - decrease HR and contractility

Answer 6

4 - decrease HR and contractility

• this reduces the oxygen demand and cardiac workload, whilst increasing perfusion

Question 7

B1 adrenergic receptors typically increase heart rate and contractility in the heart. The use of B-blockers is indicated in chronic heart failure (CHF). How do B-blockers improve prognosis in CHF?

1 - reduces parasympathetic stimulation
2 - reduces sympathetic stimulation
3 - increases parasympathetic stimulation
4 - increases sympathetic stimulation

Answer 7

2 - reduces sympathetic stimulation

Question 8

B1 adrenergic receptors typically increase heart rate and contractility in the heart. The use of B-blockers is indicated in atrial fibrillation (AF) and supra-ventricular tachycardia (SVT). How to B-blockers improve prognosis in AF and SVT?

1 - prolong refractory period of AV node and terminate SVT
2 - reduce refractory period of AV node and terminate SVT

Answer 8

1 - prolong refractory period of AV node and terminate SVT

• essentially the heart cells cannot repolarise quickly enough to maintain AF

Question 9

B1 adrenergic receptors typically increase heart rate and contractility in the heart. However, they can also be used as a 4th line treatment in resistive hypertension. Although complex, how is it thought that B-blockers are able to reduce hypertension?

1 - inhibit Ca2+ channels in smooth muscle
2 - inhibits renin release
3 - increases aldosterone release
4 - inhibits Angiotensin-converting enzyme

Answer 9

2 - inhibits renin release

• binds B1 receptors on juxtaglomerular cells
• less renin is releases, meaning reduced SVR

Question 10

B1 adrenergic receptors typically increase heart rate and contractility in the heart. However, they can also be used for migraines. How is it thought that they are able to do this?

1 - reduced dopamine release
2 - reduced glutamate release
3 - reduced neuronal activity in noradrenergic excitability

Answer 10

3 - reduced neuronal activity in noradrenergic excitability

Question 11

B1 adrenergic receptors typically increase heart rate and contractility in the heart. However, they can also be used in thyroid storm / thyrotoxicosis. How do they help alleviate this?

1 - reduce heart rate
2 - increase heart rate
3 - inhibits pituitary gland

Answer 11

1 - reduce heart rate

• reduces palpitations and tremor
• reduces B-adrenergic up regulation

Question 12

B-blockers can cause a number of adverse events. Which of the following is NOT a common adverse event?

1 - fatigue
2 - cold extremities
3 - headaches
4 - incontinence
5 - GI upset
6 - sleep disturbance
7 - impotence

Answer 12

4 - incontinence

Question 13

Which of the following conditions should B-blockers be avoided?

1 - COPD
2 - asthma
3 - diabetes
4 - crohns

Answer 13

2 - asthma

• can cause life threatening bronchospasm
• generally safe in COPD

Question 14

In patients taking B-blockers for heart failure, should they be started on the normal dose?

Answer 14

• no
• should start on a reduced dose, as cardiac function may initially be impaired

Question 15

Which of the following conditions are B-blockers ok to be used in?

1 - heart block
2 - severe hypotension
3 - significant hepatic failure
4 - diabetes

Answer 15

4 - diabetes

Question 16

Diabetic patients are at risk of hypoglycaemia. In response the body release of adrenaline, causing gluconeogeneis in the liver in an attempt to release glucose. Which of the following is NOT a common symptom a patient with diabetes can experience when hypoglycaemic due to adrenaline?

1 - sweating
2 - tremor
3 - irritation
4 - bradycardia

Answer 16

4 - bradycardia

• experience palpitations

Question 17

Why can it be dangerous for patients who are diabetic to take beta blockers?

1 - causes hyperglycaemia
2 - masks hypoglycaemia
3 - induces retinopathy
4 - increases risk of PVD

Answer 17

2 - masks hypoglycaemia

• essentially blocks the sympathetic effects (R1 receptor) symptoms associated with hypoglycaemia
• patients may be hypoglycaemic and not know

Question 18

Which of the following classes of medications should B-blockers not be prescribed alongside?

1 - cardiac glycosides
2 - class 1 antiarrhythmics
3 - anticoagulants
4 - non-dihydropyridines Ca2+ channel blockers

Answer 18

4 - non-dihydropyridines Ca2+ channel blockers

• this class of drugs work primarily on cardiac Ca2+ channels
• can cause heart failure, bradycardia and asytole.
• verapamil and diltiazem

Question 19

When prescribing B-blockers which of the following should you use?

1 - lowest dose and build up as in BNF
2 - lower than the lowest dose in BNF
3 - standard dose patient has had previously

Answer 19

1 - lowest dose and build up as in BNF

Question 20

When stoping B-blockers, why should the drugs NOT be stopped immediately?

1 - patient may not want to
2 - heart may fail
3 - hypotension can occur
4 - adrenoreceptors are up regulated and can cause surge in sympathetic stimulation

Answer 20

4 - adrenoreceptors are up regulated and can cause surge in sympathetic stimulation

• adrenoreceptors have increased sensitivity to overcome B-blockers. If B-blockers are then stopped this can cause a massive sympathetic reaction