Vasopressors

Question 1

phenylephrine

Answer 1

Noncatecholamine with mainly direct alpha1 agonist activity –> mainly causes peripheral vasoconstriction; tachyphylaxis

Question 2

Ephedrine

Answer 2

Noncatecholamine with direct an indirect effects that increase BP, HR, contractility, and CO, also bronchodilates

Question 3

What are alpha 1 receptors?

Answer 3

Postsynaptic receptors that when activated increase intracellular calcium and leads to muscle contraction

Question 4

Alpha 1 effects

Answer 4

Mydriasis, bronchoconstriction, vasoconstriction, uterine contraction, contraction of sphincters, inhibits insulin secretion and lipolysis

Question 5

What are alpha 2 receptors?

Answer 5

Presynaptic receptors that when activated inhibit adenylate cyclase that decreases entry of calcium and exocytosis of norepinephrine from vesicles

Question 6

Alpha 2 effects

Answer 6

Vasoconstriction and negative norepinephrine feedback loop; CNS receptors cause sedation and decreased sympathetic outflow

Question 7

What are beta 1 receptors?

Answer 7

Postsynaptic receptors located on the heart

Question 8

Beta 1 effects

Answer 8

Positive chronotrope (HR), dromotrope (conduction), inotrope (contractility)

Question 9

What are beta 2 receptors?

Answer 9

Postsynaptic receptors found in smooth muscle and glands

Question 10

Beta 2 effects

Answer 10

Relaxes smooth muscle - bronchodilation, vasodilation, relaxation of uterus (tocolysis), bladder, and gut, stimulates glycogenolysis, gluconeogenesis, and insulin release; activates sodium/potassium pump (K into cell)

Question 11

What is methyldopa? Effects?

Answer 11

Alpha 2 agonist that is converted to alpha methylnorepinephrine and alpha methylepinephrine, and caused decreased norepinephrine release and sympathetic tone

Question 12

What is clonidine? Effects?

Answer 12

Alpha 2 agonist that is a sedative, anxiolytic, analgesic, antihypertensive, and negative chronotrope, bradycardia, respiratory depression

Question 13

What is dexmedetomidine? Effects?

Answer 13

Alpha 2 agonist that causes sedation, analgesia, and sympatholytic without significant respiratory depression

Question 14

What happens with rapid dexmedetomidine administration?

Answer 14

HTN but ongoing therapy can cause hypotension and bradycardia

Question 15

Epinephrine beta 1

Answer 15

Direct beta 1 stimulation causes increase CO and myocardial demand by increasing contractility and HR

Question 16

Epinephrine alpha 1

Answer 16

Decreases splanchnic and renal blood flow, increase coronary and cerebral perfusion pressure

Question 17

Epinephrine beta 2

Answer 17

Relaxes bronchial smooth muscle, vasodilation in skeletal muscle may decrease diastolic BP

Question 18

Epinephrine 1:1,000

Answer 18

1 mg per ml

Question 19

Epinephrine 1:10,000

Answer 19

100 mcg/ml (0.1 mg/ml)

Question 20

Epinephrine 1:100,000

Answer 20

10 mcg/ml (0.01 mg/ml)

Question 21

Epinephrine 1:200,000

Answer 21

5 mcg/ml (0.005 mg/ml)

Question 22

What is norepinephrine?

Answer 22

Direct alpha 1 and beta 1 stimulation

Question 23

What is dobutamine? Effects?

Answer 23

Relatively selective beta 1 agonist increases CO and contractility, less increase in HR , while beta 2 prevents increased BP –> LV filling pressure decreases and coronary blood flow increases

Question 24

Which patient is ideal for dobutamine?

Answer 24

Patients with CAD and CHF especially if peripheral vascular resistance and HR are high