Synethetic Catecholamines

Question 1

Dobutamine Class

Answer 1

Synthetic catecholamine, selective beta 1 adrenergic agonist

Question 2

Dobutamine MOA

Answer 2

Synthetic analog of isoproterenol

Acts on B1, G proteins to increase cAMP, influx of Ca causing increased contractility & CO

Some B2 (vasodilation, decrease SVR) & A1 (minimum)

Question 3

Dobutamine Uses (3)

Answer 3

Cardiogenic and septic shock
Treat mild CHF
Cardiac stress tests

Question 4

Dobutamine Dose

Answer 4

Infusion: 2 to 20 mcg/kg/min

Question 5

Dobutamine Onset and DOA

Answer 5

Onset: 1 minute
DOA: 10 minutes

Question 6

Dobutamine Metabolism

Answer 6

MAO, COMT

Question 7

Dobutamine Excretion

Answer 7

Renally excreted

Question 8

Dobutamine Admin Considerations

Answer 8

Caution in patients with tachycardia, CAD, hypertrophic cardiomyopathy

Decrease SVR, platelet inhibition

Question 9

Phenylephrine Class

Answer 9

Selective Alpha 1 adrenergic agonist

Question 10

Phenylephrine MOA

Answer 10

Agonizes A1 receptors, triggering a G protein response to ⬆️ cAMP -> ⬆️ Ca, resulting in ⬆️ BP

Question 11

Phenylephrine Uses (2)

Answer 11

Vasodilatory shock

Hypotension (with a normal heart rate) s/p spinal anesthesia

Question 12

Phenylephrine Dosing

Answer 12

Small boluses of 40-80 mcg

Infusion: 20 – 50 mcg/min

Question 13

Phenylephrine Onset and DOA

Answer 13

Onset: 1 minutes
DOA: 15 minutes

Question 14

Phenylephrine Metabolism

Answer 14

MAO

Question 15

Phenylephrine Excretion

Answer 15

Renally excreted

Question 16

Phenylephrine Admin Considerations

Answer 16

Reflex bradycardia mediated by the vagus nerve can reduce cardiac output

Caution in patients with bradycardia, hyperthyroidism, pheochromocytoma

Phenylephrinemust be diluted from a 1% solution (10 mg/1-mL ampule), usually to a 100 mcg/mL solution and titrated to effect

Question 17

Vasopressin Class

Answer 17

Exogenous antidiuretic peptide & vasopressor

Question 18

Vasopressin MOA

Answer 18

Agonizes vasopressin receptors.

V1: constriction of vascular smooth muscle

V2: in DCT & collecting ducts of kidneys = increased water reabsorption

Question 19

Vasopressin Uses (3)

Answer 19

Septic shock

Post–cardiopulmonary bypass shock state

ACE Inhibitor related hypotension

Question 20

Vasopressin Dosing

Answer 20

Bolus: 1 – 20 units
Infusion: 0.01-0.04 units/min

Question 21

Vasopressin Onset and DOA

Answer 21

Onset: 1 minutes
DOA: 10 minutes

Question 22

Vasopressin Metabolism

Answer 22

Tissue peptidase

Question 23

Vasopressin Excretion

Answer 23

Renally excreted

Question 24

Vasopressin Admin Considerations (4)

Answer 24

Gastrointestinal ischemia

Decreased cardiac output

Skin or digital necrosis

Cardiac arrest (especially at doses greater than 0.04 units/min)

Question 25

Milrinone Class

Answer 25

Phosphodiesterase 3 Inhibitor

Question 26

Milrinone MOA (4)

Answer 26

Inhibits PDE III which degrades cAMP cAMP buildup in cardiac smooth muscle causes increased contractility & HR cAMP buildup in vascular smooth muscle causes decreased PVR & SVR Overall increase in CO

Question 27

Milrinone Uses (4)

Answer 27

Cardiogenic shock Right heart failure Dilates pulmonary artery Inotropy in the setting of beta blockade

Question 28

Milrinone Dosing

Answer 28

Loading dose: 50 mcg/kg over 10 minutes Infusion: 0.375–0.75 mcg/kg/min

Question 29

Milrinone Onset

Answer 29

Onset: 5 – 15 minutes

Question 30

Milrinone Elimination

Answer 30

Renally excreted (80% unchanged)

Question 31

Milrinone Metabolism

Answer 31

Minor Hepatic Metabolism (20%) Rest not metabolized

Question 32

Milrinone Admin Considerations

Answer 32

Caution in patients with hypotension, renal failure Side effects include arrythmias

Question 33

Ephedrine Class

Answer 33

Synthetic noncatecholamine, indirect and direct acting

Question 34

Ephedrine MOA

Answer 34

It stimulates both α- and β-receptors directly, and it indirectly causes release of endogenous catecholamines, leading to multiple mechanisms of action. It has both central and peripheral actions.

Question 35

Ephedrine Uses (3)

Answer 35

Treat hypotension with bradycardia Used w/ GA or SNS blockade to treat hypotension caused by bradycardia after spinal Like epinephrine, but weaker action and lasts 10x longer

Question 36

Ephedrine Doses

Answer 36

Small Bolus: 5 - 10 mg

Question 37

Ephedrine Onset and DOA

Answer 37

Onset: 1 minutes DOA: 10 – 60 minutes

Question 38

Ephedrine Metabolism

Answer 38

Resistant to MAO since lacks catecholamine

Question 39

Ephedrine Excretion

Answer 39

Renally excreted (40% unchanged)

Question 40

Ephedrine Admin Considerations (4)

Answer 40

Risk for those with CAD, tachycardia, hypertension Patients taking MAOIs, TCAs & cocaine Caution in trauma because subsequent doses are increased to offset the development of tachyphylaxis, which is probably due to depletion of norepinephrine stores.  Ephedrine is available in 1-mL ampules containing 25 or 50 mg of the agent

Question 41

Albuterol Class

Answer 41

Selective B2 agonist

Question 42

Albuterol MOA

Answer 42

Acts directly on Beta 2 receptors coupled to G protein Activates adenylyl cyclase which increases cAMP and decreases Ca++ Increases K+ conductance causing smooth muscle relaxation & bronchodilation

Question 43

Albuterol Uses

Answer 43

Bronchodilation

Question 44

Albuterol Dosing

Answer 44

90 mcg per puff

Question 45

Albuterol Onset and Duration

Answer 45

Onset: 5 minutes DOA: 4 hours

Question 46

Albuterol Metabolism

Answer 46

MAO

Question 47

Albuterol Excretion

Answer 47

Renally excreted (30 % unchanged)

Question 48

Albuterol Admin Considerations (3)

Answer 48

Tremors Tachycardia Hypokalemia