Drugs For The CVS

Question 1

Name some types of arrhythmias

Answer 1

Bradycardia, tachycardia, atrial flutter, atrial fibrillation, ventricular fibrillation.

Question 2

Why is VF (ventricular fibrillation) so dangerous?

Answer 2

Causes cardiac output to drop drastically

Question 3

What could cause an arrhythmia?

Answer 3

Ectopic pacemaker activity, re-entry loops, after-depolarisations

Question 4

What are the main/general actions of drugs when targeting the heart

Answer 4

To deal with rate, rhythm of heart, force of myocardial contraction, peripheral resistance/blood flow, blood volume

Question 5

Drugs that aim to correct arrhythmias, what are their main targets?

Answer 5

Block Na+ channels, block K+ channels, block Ca2+ channels, B-adrenoceptor antagonists

Question 6

Give an example of a Na+ channel blocker used

Answer 6

Lidocaine (given IV)

Question 7

Give an example of a B blocker?

Answer 7

Propranolol, Atenolol, Esmolol

Question 8

Give an example of a K+ channel blocker that is used

Answer 8

Amiodarone

Question 9

Give an example of a Ca2+ channel blocker thats used

Answer 9

Verapamil

Question 10

What are the steps in the Renin Angiotensin System?

Answer 10

Pre-enzyme Angiotensinogen converted to Angiotensin I by Renin. ANG I converted to ANG II by angiotensin converting enzyme (ACE)

Question 11

Where is renin produced and why?

Answer 11

The kidneys, in response to low fluid volume in nephrons

Question 12

Where is ACE present?

Answer 12

In the lungs

Question 13

What is the mechanism of action of ANG II?

Answer 13

Acts on adrenal glands to produce aldosterone (from zona glomerulosa). Aldosterone then acts on collecting ducts of kidney tubules to bring water into cell following movement of Na+, meaning BP increases due to more water

Question 14

Why would ACE inhibitors be useful for heart failure?

Answer 14

Prevent conversion of ANG I to ANG II which would reduce amount of aldosterone produced, meaning less water taken back up into blood decreasing BP and TF workload for heart

Question 15

Why is high BP bad for heart failure?

Answer 15

High BP would increase workload for heart, putting it under further stress

Question 16

Define angina

Answer 16

Uncomfortable sensation in the chest (and nearby areas) caused by myocardial ischaemia which recedes after rest

Question 17

Why does angina present during exertion?

Answer 17

Eg in exercise, HR rises, so length of diastole shortens, diastole is when the coronary arteries are filled most and so heart muscle itself is most perfused during diastole, TF ischaemia.

Question 18

What are the main aims of drugs trying to treat angina?

Answer 18

Decrease workload or improve blood supply

Question 19

What drugs would work to decrease workload in angina?

Answer 19

B blockers, Ca2+ channel blockers, organic nitrates.

Question 20

What drugs would work to improve blood supply in angina?

Answer 20

Organic nitrates, Ca2+ channel blockers

Question 21

How do organic nitrates help heart?

Answer 21

Organic nitrates react (with thiol groups in vascular smooth muscle) to release NO2-, this is then reduced to NO which is a powerful vasodilator

Question 22

How does NO cause vasodilation?

Answer 22

NO activates guanylate cyclase, which converts GTP-> cGMP, this activates Protein Kinase G. This triggers the re-uptake of Calcium (less Ca2+, less MLCK activated, less phosphorylated MLC, TF SM relaxation)

Question 23

Name an anti-platelet drug

Answer 23

Aspirin

Question 24

Name anti-coagulant drugs

Answer 24

Heparin, Warfarin

Question 25

What is BP equal to?

Answer 25

Cardiac output X total peripheral resistance

Question 26

How could you treat hypertension?

Answer 26

Decrease blood volume (diuretics), decrease CO (B blockers, Ca2+ channel blockers, alpha 1 adrenoceptor agonists), decrease TPR (ACE-inhibitors)

Question 27

What is hypertension defined as?

Answer 27

BP of over 140/90 mmHg