Autonomic pharmacology

Question 1

What is the CNS nucleus or region of the Sympathetic and Parasympathetic systems?

Answer 1

Sympathetic => Rostral ventrolateral medulla (RVLM) Parasympathetic => Nucleus Ambiguus

Question 2

What is the exit spinal cord for the Sympathetic and Parasympathetic systems?

Answer 2

Sympathetic => T1-L5 Parasympathetic => CN III, VII, IX, X and S2-4

Question 3

Describe the pre/post-ganglionic fibers of the Sympathetic and Parasympathetic systems.

Answer 3

Sympathetic => short pre-ganglionic fibers; long post-ganglionic fibers Parasympathetic => long pre-ganglionic fibers; short post-ganglionic fibers

Question 4

What is the ganglionic transmitter for the Sympathetic and Parasympathetic systems?

Answer 4

The sympathetic and parasympathetic BOTH use ACETYLCHOLINE as their ganglionic transmitter

Question 5

What do Sympathetic and Parasympathetic post-ganglionic fibers release?

Answer 5

Sympathetic post-ganglionic fibers: - Norepinephrine –> cardiac muscle, smooth muscle, gland cells - Acetylcholine –> sweat glands - Dopamine –> renal vascular smooth muscle - Epinephrine + Norepinephrine –> adrenal medulla Parasympathetic post-ganglionic fibers: - Acetylcholine –> cardiac muscle, smooth muscle, gland cells

Question 6

Which nerves make and package Ach and NE?

Answer 6

CHOLINERGIC nerves make and package–> Ach NORADRENERGIC nerves make and package –> NE

Question 7

Name important cholinoceptors in the PNS.

Answer 7

Question 8

Name important adrenoceptors in the sympathetic nervous system.

Answer 8

Question 9

Describe what happens when your BP drops

Answer 9

1) Drop in BP is detected by vasomotor centers => activates the sympathetic autonomic nervous system (SANS)
2) SANS => constrict arterioles => increase in SVR/TPR => Increase in BP (MAP)
3) SANS => SA node => Increase in HR => Increase in CO => Increase in BP
4) SANS => LV => Increase contractility => Increases SV => Increase CO => Increase BP
5) SANS => Veins => Increase venomotor tone => Increase venous return => Increase SV
6) SANS => kidneys => Increase NaCl retention => Increase venous treurn => Increase SV
9) SANS => adrenals => Increase NE + Epi
7) Drop in BP is detected by vasomotor centers => depress parasympathetic autonomic nervous system => depression of SA node => Increase HR
8) Drop in BP is detected by baro-receptors => pituitary => Increase ADH => increase water retention => increase SV

Question 10

Norepinephrine Pharm Card

Answer 10

Also known as: Noradrenaline, Levophed™

Question 11

Epinephrine Pharm Card

Answer 11

Also known as: adrenaline,EpiPen™

Question 12

What is the drug class for NE?

Answer 12

NE pharmacologic class: direct acting adrenergic agonist

NE therapeutic class: vasopressor, vasoconstrictor

Question 13

Describe NE pharmacodynamics.

Answer 13

NE Pharmaco dynamics:

Major action => Vasoconstriction and cardiac stimulation

1) Stimulates peripheral alpha-1 adrenoceptors
- Leads to vasoconstriction (resistance arterioles, increase SVR) and venoconstriction (in capacitance vessels, increase prelaod)
- Increases CO, SVR, and MAP
- Decreases blood flow to skin, muscle, and kidney
2) Stimulates beta-1 receptors in the heart
- Increases HR and contractility

Question 14

Describe NE pharmacokinetics.

Answer 14

• F ~ 100%
• Given IV ONLY
• Metabolized by COMT and MAO (liver)
• Metabolites are excreted in urine
• T1/2 = 1-2 minutes (can be titrated quickly IV)
• Can cross the placenta, but NOT blood/brain barrier

Question 15

Describe NE toxicity.

Answer 15

1) Excessive vasoconstriction in mesenteric vessels, peripheral arterioles
- Leads to ischemia, infarction, and gangrene

* Reflex => bradycardia

Question 16

Describe NE interactions.

Answer 16

1) Use cautiously in patients taking an MAO inhibitor (ie Phenelzine-use lower doses)
2) Risk of excessive hypertension in patints taking propranolol

Question 17

What are special considerations for NE?

Answer 17

1) Correct volume depletion with IV fluids BEFORE giving NE infusion
2) Select infusion site carefully => extravasation is a major problem
3) Monitor patient and BP continuously in an ICU setting
4) Use catiously in pediatric and geriatric patients

Question 18

What are the indications for NE use/dose/route?

Answer 18

• Used in adults with acute HYPOTENSION and SHOCK (related to low SVR)
• Infuse 2-12 mcg/min

Question 19

What should be monitored in patients taking NE?

Answer 19

• BP
• HR
• Infusion site
• Evidence of extravasation

Question 20

What is the drug class for Epi?

Answer 20

Epi pharmacologic class => direct acting adrenergic agonist

Epi therapeutic class => vasopressor, cardiac stimulatnt, bronchodilator, adjunct to local anesthetics, treatmetn ofr anaphylaxis

Question 21

Describe Epi pharmacodynamics.

Answer 21

Major action:

1) Stimulate peripheral alpha-1 adrenoceptors
- Vasoconstriction => resistance arteriles, increase SVR
- Venoconstriction => capacitance vessels, increase preload
2) Beta-1 receptors
- Tachycardia => increased contractility
3) Beta-2 receptors
- Bronchodilation => helpful in severe allergic reactions by stabilizing mast cells (anaphylaxis)

Question 22

Describe Epi pharmacokinetics.

Answer 22

1) Can be given by:
- IV => immediate
- Intramuscular => variable
- Subcutaneously => 5-15 minutes
- Inhalation => 1-5 minutes onset
- Opthalmic => topical
2) Metabolized by COMT
3) Renally excreted

Question 23

Describe Epi toxicity.

Answer 23

1) Excessive vasoconstriction
- HTN
- Hemorrhagic stroke
- Angina
- Arrythimas

Question 24

Describe Epi interactions.

Answer 24

• Risk of excessive HTN in patients taking propranolol

Question 25

What are special considerations for Epi?

Answer 25

1) Utility with local anesthetics
2) Drug of choice in severe anaphylactic reactions

Question 26

What are the indications for Epi use/dose/route?

Answer 26

1) For anaphylaxis:
- 0.1-0.5 mg => Subcutaneously (SC) or Intramuscularly
2) For cardiac arrest:
- 1-5 mg IV push
- 1-4 mcg/min for infusion

Question 27

What should be monitored in patients on Epi?

Answer 27

• BP
• HR
• Rhythm
• Infusion site
• Evidence of extravasation