Vasodilators NOT FINISHED

Question 1

What are the three types of physiological control of vascular tone?

Answer 1

autonomic innervation
circulating hormones
local mediators

Question 2

What are indirect vasodilators?

Answer 2

drugs which block vasoconstriction
ANS - sympathetic blockade
RAAS - angiotensin II is a vasoconstrictor

Question 3

What are the 6 clinical uses of direct vasodilators?

Answer 3

1. hypertension
2. angina pectoris
3. peripheral vascular disease
4. impotence
5. hair loss
6. improved cerebral function

Question 4

What is angina pectoris?

Answer 4

pain due to inadequate coronary blood flow
atheromatous obstruction
arterial spasm

Question 5

What are the 3 drug classes used to treat angina pectoris

Answer 5

A. NOT vasodilators
B. organic nitrates
C. calcium channel blockers

Question 6

What are two drugs in the ‘not vasodilators’ class A?

Answer 6

i. beta blockers - decrease cardiac work (but exercise intolerance
ii ivabradine - affects a channel of pacemaker current

Question 7

Give an example of an organic nitrate
What is its mechanism of action?
Where does it have its greatest affect?
Does it have a direct effect on coronary vessels?

Answer 7

• glyceryl trinitrate (GTN)
• NO, activates guanylate cyclase, reduces cross bridge formation –> vasodilation
• affects veins more than arteries in systemic vessels, increases venous return –> increases preload
• may increase coronary flow but little affect due to plaque. decreases venous retune and so decreases cardiac work

Question 8

What are some unwanted affects of GTN?

Answer 8

excess vasodilation

• hypotension –> syncope, reflex tachycardia
• headache –> cerebral vasodilation
• other smooth muscle –> GIT (constipation)

Question 9

How can GTN be administered?

Answer 9

sublingual 
- avoids 1st pass metabolisms
- fast acting but short duration 
transdermal for prophylaxis 
- patches on skin

Question 10

What are two other therapeutic issues with GTN?

Answer 10

physiological tolerance - compensation via a different mechanism
pharmacological tolerance - machinery within cells become less sensitive over time

Question 11

What is isosorbide mononitrate?

Answer 11

alternative to GTN in angina
rarely used
different pharmacokinetics to GTN
longer duration, orally active, more side effects