Drugs affecting blood vessel diameter and volume

Question 1

How can preload be altered?

Answer 1

Alter venous/atrial volume

Alter venous diameter

Question 2

How is after load altered?

Answer 2

Alter TPR

Question 3

How is perfusion altered?

Answer 3

Alter CO
Alter vessel diameter
Alter circulating volume

Question 4

How is systemic arterial pressure altered?

Answer 4

Alter CO

Alter TPR

Question 5

Why would you want to affect blood diameter/volume?

Answer 5

Hypertension

Forwards and backwards heart failure

Question 6

What are the 2 types of endogenous mechanisms that alter blood flow?

Answer 6

Intrinsic - paracrine, autoregulation

Extrinsic - ANS, baroreceptors, RAAS, hypothalamus, pituitary

Question 7

What are the types of vasodilators?

Answer 7

Venodilators, arteriodilators, mixced
Direct - act on smooth muscle of vessels, faster acting
Indirect - act on another system, longer acting

Question 8

What are examples of direct vasodilators?

Answer 8

Nitrates
Calcium channel blockers
PDE III inhibitors
Hydralazine 
(dopamine, K channel activators)

Question 9

How do nitrates work as vasodilators?

Answer 9

Via nitric oxide action

cGMP causes activation of MLCP - smooth muscle relaxation

Question 10

Give an example of a nitrate used for vasodilation. Is it artery or vein dilation? How does it work?

Answer 10

Nitroglycerine
Venodilator
Metabolised to NO in vascular smooth muscle

Question 11

How is nitroglycerine administered?

Answer 11

Topical

Extensive first pass metabolism on oral administration

Question 12

What are the adverse effects of nitroglycerine?

Answer 12

Hypotension

Question 13

Calcium channel blockers are also used as vasodilators. What class of antidysrhythmics are calcium channel blockers? Give an example

Answer 13

Class IV antidysrhythmics

Amlodipine

Question 14

What are the adverse effects of amlodipine?

Answer 14

Hypotension

Inappetance, azotaemia, reflex tachycardia

Question 15

Is hydralazine arteriodilator, venodiltor or both? Where does it have its main effects?

Answer 15

Arteriodilator

Coronary, cerebral, renal and splanchnic circulation (abdomen)

Question 16

Does hydralazine have a known MOA? What does this drug cause?

Answer 16

No

Arteriodilation - increased CO and reflex tachycardia (tachycardia due to drop in blood volume)

Question 17

How is hydralazine administered and excreted?

Answer 17

Oral administration

Excreted unchanged in urine

Question 18

What are PDE III inhibitors used for?

Answer 18

Congestive heart failure

Question 19

Give an example of a PDE V inhibitor. What type of vasodilator is this? How is it administered? What are the adverse effects?

Answer 19

Slidenafil (viagra)
Arteriodilator
Oral administration
Hypotension

Question 20

What drugs are used to affect RAAS?

Answer 20

ACE inhibitors

Aldosterone antagonists

Question 21

What do ACE inhibitors cause? What are potential adverse effects?

Answer 21

Vasodilation
Reduced circulating volume
Adverse- hypotension

Question 22

Give an example of an ACE Inhibitor? How is it administered, metabolised and excreted?

Answer 22

Benazepril
Oral
Metabolised in liver
Excreted in urine and bile

Question 23

Give an example of an Angotensin II receptor antagonist

Answer 23

Telmisartan

Question 24

What are aldosterone antagonists originally used as? Give an example

Answer 24

Potassium sparing diuretics

Spironolactone

Question 25

What do aldosterone antagonists do to decrease blood pressure?

Answer 25

Reduce retention of sodium and water

Reduce K loss - contraindicated in hyperkalaemia

Question 26

What drugs can be given to reduce preload? What can be an adverse effect on this?

Answer 26

Diuretics

Oedema