Vasoactive drugs

Question 1

Describe the effects of inotropes, vasopressors and inodilators

Answer 1

inotropes - increase cardiac contractility
vasopressors - vasoconstrict
inodilators - increase contractility + vasodilate

Question 2

Give examples of inotropes

Answer 2

adrenaline
dobutamine
isoprenaline
ephedrine

Question 3

Result of a1 stimulation

Answer 3

smooth muscle contraction
mydriasis
vasoconstriction in the skin

Question 4

Result of a2 stimulation

Answer 4

mixed effects on smooth muscle
platelet activation
noradrenaline inhibition

Question 5

Result of a3 stimulation

Answer 5

positive chonotropy and inotropy

Question 6

Result of beta adrenergic receptor stimulation

Answer 6

B1: positive chonotrpy and inotropy
B2: airway smooth muscle relaxation, insulin release, histamine inhibition, enhanced lipolysis
B3: enhanced lipolysis

Question 7

Compare the receptor selectivity of adrenaline, noradrenaline and dopamine

Answer 7

adrenaline: slightly more b selective
noradrenaline: alpha selective
dopamine: dopaminergic>beta>alpha

Question 8

State some advantages of adrenaline, noradrenaline and dopamine

Answer 8

titetratable
familiar
available

Question 9

State some disadvantages/complications of adrenaline

Answer 9

lactic acidosis

hypokalaemia

Question 10

State some disadvantages/complications of noradrenaline

Answer 10

reflex bradycardia

hypertension

Question 11

State some disadvantages/complications of dopamine

Answer 11

arrhythmias

imunne dysregulation

Question 12

Give examples of vasopressors

Answer 12

Noradrenaline
Vasopressin
Metaraminol

Question 13

Give examples of inodilators

Answer 13

Dobutamine
Milrinone
Livosimendan

Question 14

What receptor does phenylephrine act on

Answer 14

alpha - it vasocontricts

Question 15

what type of vasoactive drug is dobutamine? What receptors does it act on?

Answer 15

inodilator - increased pumping against lower resistance

beta agonist and alpha antagonist

Question 16

What are some adverse effects of dobutamine

Answer 16

arrhythmias
tachyphylaxis
myocardial ischaemia

Question 17

What are the effects of vasopressin on V1,V2 and V3/V1b receptors

Answer 17

V1 - vasoconstriction with sparing of myocardium, cerebrum and mesenteric
V2 - AQP2 receptors intergrated into membrane
V3/V1b - ACTH release so increased cortisol

Question 18

isoprenaline and ephedrine are inotropes acting on which receptor primarily

Answer 18

beta

Question 19

How do milrinone and levosimendan work?

Answer 19

milrinone - phosphodiesterase inhibitor

levosimendan - phosphodiesterase inhibitor and calcium sensitizer

Question 20

What is an adverse effect of the phosphodiesterase inhibitors?

Answer 20

hypotension

Question 21

In a hypotensive spinal cord injury patient, which vasoactive drug would you use and why

Answer 21

phenylephrine - the patient is likely hypotensive because of vasodilation so you want to vasoconstrict

Question 22

A trauma patient is in ICU on day 3 and becomes hypotensive, why could this be

Answer 22

rebleed

infection/inflammation leading to a SIRS type response

Question 23

State some ways inotropes work

Answer 23

activation of g-protein coupled receptors
increase in extracellular calcium
inhibition of phosphodiesterase (decrease breakdown of cAMP so increased inward Ca current)
myocyte calcium sensitization

Question 24

activation of B3 receptors leads to what

Answer 24

enhanced lipolysis

detrusor muscle relaxation

Question 25

What is the MOI of Metaraminol

Answer 25

Activation of a1

inhibits noradrenaline reuptake