Week 4 ANS Drugs

Question 1

3 Components of Cushing’s Triad

Answer 1

Increased ICP
Bradycardia
HTN

Question 2

Describe Autonomic HYPERreflexia

Answer 2

Systemic HTN due to intense vasoconstriction, reflecting an inability of vasodilating inhibitory impulses from the CNS to pass beyond a spinal cord transection site
There is a loss if inhibitory impulses resulting in pure SNS stimulation
Spine injury generally at T5 or higher

Question 3

Describe Baroreceptor Reflex

Answer 3

Stretch Receptors in Aorta & Carotid Arteries sense Increased BP–>
Signal sent via Vagus nerve–>
HR Decreased

Question 4

Describe Central & Peripheral Chemoreceptor Reflexes

Answer 4

Central Chemoreceptor: Senses Increased arterial CO2 and/or Decreased arterial pH–>Causes increased TV and RR (aka Increased Minute Ventilation)
Peripheral Chemoreceptor: Senses Decreased O2 in Carotid Bodies–>Causes increased TV and RR (aka Increased Minute Ventilation)

Question 5

Describe Bainbridge Reflex

Answer 5

Increase HR d/t Increase in CVP sensed by Atrial Stretch Receptors (aka Atrial Reflex)

Question 6

Describe the Bezold-Jarisch Reflex

Answer 6

Vagally mediated reflex of the heart causing Hypotension, Bradycardia, & Coronary Dilation–> Cardioprotective

Question 7

Describe OculoCardiac (Five & Dime) Reflex

Answer 7

Decreased HR d/t pressure on eye via CNs 5 and 10

Question 8

Norepinephrine is the _______ POST-ganglionic neurotransmitter.

Answer 8

Norepinephrine is the Sympathetic Nervous System POST-ganglionic neurotransmitter.

Question 9

Acetylcholine is a neurotransmitter of which nervous system? Sympathetic or Parasympathetic? Explain.

Answer 9

ACh is the Sympathetic and Parasympathetic PRE-ganglionic neurotransmitter AND the Parasympathetic POST-ganglionic neurotransmitter

Question 10

Epinephrine
Where is it synthesized?
Infusion Doses and Receptors Activated

Answer 10

Synthesized in the Adrenal Medulla
2-10mcg/min (Beta 1, Beta 2)
>10mcg/min (Alpha 1)
MAX 20mcg/min

Question 11

Norepinephrine

Infusion Doses and Receptors Activated

Answer 11

4-12mcg/min
Lower Doses activate Beta 1
Higher Doses activate Alpha 1
MAX 16mcg/min

Question 12

Dopamine

Infusion Doses and Receptors Activated

Answer 12

1-3mcg/kg/min (D1, D2)
3-10mcg/kg/min (Beta 1)
>10mcg/kg/min (Alpha 1)
MAX 20mcg/kg/min

Question 13

Fenoldopam

Infusion Doses and Receptors Activated

Answer 13

0.1-0.8mcg/kg/min (D1 Renal Receptors)

Question 14

Phenylephrine

Bolus/Infusion Doses and Receptors Activated

Answer 14

Bolus Dose: 50-100mcg
Infusion Dose: 20-50 mcg/min
(Alpha 1 venous>Alpha 1 arterial)

Question 15

Phentolamine
Use
Mechanism of Action

Answer 15

Phenylephrine OverDose, NE Infiltration

Non-Selective Alpha Antagonist

Question 16

Midodrine
Use
Mechanism of Action

Answer 16

Dialysis Induced Hypotension

Oral Alpha 1 Agonist

Question 17

Ephedrine

Mechanism of Action

Answer 17

Direct and Indirect-Acting Sympathomimetic: acts directly on Alpha and Beta receptors, acts indirectly by competing with NE for re-uptake in vesicles so that NE can stay at receptor sites longer

Question 18

Does Ephedrine Increase or Decrease MAC required?

Any other Sympathomimetics that affect MAC dose?

Answer 18

Increases MAC d/t CNS Stimulation

Yes, Epinephrine and Isoproterenol

Question 19

Clonidine
Use
Mechanism of Action

Answer 19

Resistant HTN, Prolong Spinals
Partial Alpha 2 Agonist
*Black Box for Pregnant Women

Question 20

Isoproterenol
Use
Mechanism of Action

Answer 20

As “Chemical Pacemaker” til Permanent Pacemaker can be placed
Non-selective Beta 1, Beta 2 Agonist

Question 21

Dobutamine
Use
Mechanism of Action

Answer 21

Improve Cardiac Output in CHF patients
Racemic Mixture: Beta 1 Agonist, Alpha 1 Agonist, and Alpha 1 Antagonist (Positive Inotropic agent)
*Has Ceiling Effect (Peak Effect) with respect to vasodilation @ Doses >5mcg/kg/min

Question 22

Albuterol and Metaproterenol
Use
Mechanism of Action

Answer 22

Asthma, COPD

Beta 2 Agonists: bronchodilation

Question 23

Terbutaline
Use
Mechanism of Action

Answer 23

Asthma, Tocolysis (Stop pre-mature contractions)

Beta 2 Agonist: bronchodilation and uterine smooth muscle relaxation

Question 24

Vasopressin
Use
Mechanism of Action
Dosages

Answer 24

Codes, Refractory Hypotension (d/t ACEIs or ARBs)
Stimulation of V1 receptors on vascular smooth muscle- causes vasoconstriction
Code Dose: 40 unit Bolus
Intraoperative Dose: 1-8 units IV

Question 25

Phenoxybenzamine Use Mechanism of Action

Answer 25

HTN in Pheochromocytoma patients | Non-Selective Alpha Antagonist (Alpha1>Alpha2)

Question 26

Prazosin Use Mechanism of Action

Answer 26

HTN | Selective Alpha 1 Antagonist

Question 27

Doxazosin and Tamsulosin Use Mechanism of Action

Answer 27

BPH | Selective Alpha 1 Antagonist

Question 28

Metoprolol Use Mechanism of Action Dose

Answer 28

Control HR when BP reduction NOT needed Selective Beta 1 Antagonist Dose: 2-5mg IV q2-5mins (Total dose 15mg)

Question 29

``` Esmolol Use Mechanism of Action Metabolism Onset of Action Bolus and Infusion Dose ```

Answer 29

``` Fast BP control for Short Duration Selective Beta 1 Antagonist Metabolized by Non-specific Red Cell Esterase Onset: 90 secs Bolus Dose: 10-80mg IV Infusion Dose: 50-300mcg/kg/min ```

Question 30

``` Labetalol Use Mechanism of Action Dose Onset of Action Duration of Action ```

Answer 30

``` Continued BP Control Beta 1, Beta 2 Antagonist>Alpha 1 Antagonist Dose: 5-10mg Bolus q10 mins Onset: 5-15mins DOA: 4-6 hours (long duration) ```

Question 31

Propranolol | Mechanism of Action

Answer 31

Non-Selective Beta Antagonist

Question 32

Atropine Mechanism of Action Dose

Answer 32

Anticholinergic Muscarinic Blockers Dose: 0.5-1mg IV *Tertiary Amine-->Crosses BBB (Shorter DOA than Glycopyrrolate)

Question 33

Glycopyrrolate | Mechanism of Action

Answer 33

Anticholinergic Muscarinic Blocker *Quartenary Amine-->does NOT cross BBB (Longer DOA than Atropine)

Question 34

Reserpine and alpha-Methyldopa | Mechanism of Action

Answer 34

Adrenergic Blockers: Blocks the synthesis and storage of NE