IV Anesthetics

Question 1

Anesthetic action (2)

Answer 1

1) Enhance inhibitory synaptic activity

2) Diminish excitatory activity

Question 2

Glutamate

Answer 2

Excitatory (NMDA/AMPA/Kainate)

Question 3

Glycine

Answer 3

Inhibitory (increase Cl conductance)

Question 4

GABA

Answer 4

A: Inhibitory (increase Cl conductance)
B: Inhibitory (decrease Ca++ conductance: presynaptic) Inhibitory (increase K+ conductance: postsynaptic)

Question 5

Where do barbiturates act?

Answer 5

GABA A receptors (enhance) and depress glutamate binding to AMPA receptor

Question 6

Where does propofol act?

Answer 6

GABA A and Glycine receptors (enhance)

Question 7

Where does Etomidate act?

Answer 7

GABA A receptors enhance)

Question 8

Where does ketamine act?

Answer 8

NMDA and nACh (inhibits)

Question 9

Where do Benzodiazepine’s act?

Answer 9

GABA A and Glycine (enhance)

Question 10

Where do Inhaled agents act?

Answer 10

GABA A and K+ channels (enhance);

N2O on NMDA receptors (inhibit)

Question 11

Explain sedation.

Answer 11

Calming/drowsiness/ decreased activity of excitement/anxiolytic

Question 12

Explain Hypnosis.

Answer 12

Facilitates the onset and being of a state of sleep.

Question 13

Explain Anesthesia.

Answer 13

Global but reversible CNS depression. Results in loss of response to and perception of external stimuli.

• amnesia
• immobility to noxious stimuli
• analgesia
• unconsciousness

Question 14

Which channels, pre or post, are important in setting the resting membrane potential of neurons?

Answer 14

Post-synaptic channels.

Question 15

Explain the GABA receptor complex.

Answer 15

Pentameric structure with alpha(2)/beta(2) and gamma(1) subunits.

Question 16

Where does GABA bind?

Answer 16

between alpha and beta subunits

Question 17

Where do Benzodiazepines/Flumazenil bind?

Answer 17

between the alpha and gamma subunit

Question 18

After an IV dose, where do drugs accumulate first? (3)

Answer 18

First to last:

1) Brain/Viscera
2) Lean Tissues
3) Fat

Question 19

What is context sensitivity?

Answer 19

The time is takes for blood concentrations of a drug to reach 50% after infusion has discontinued.

Question 20

Where are barbiturates derived from?

Answer 20

Barbituric Acid

Question 21

What makes Thiamylal and Thiopental more potent?

Answer 21

Replacing the oxygen at C2 with a sulfur atom. –> more potent/shorter duration of action (THIObarbiturates)

Question 22

What is special about the barbiturate methohexital?

Answer 22

The methyl group prevents the drug from being anti-convulsive. Used in ECT.

Question 23

What is special about the barbiturate phenobarbital?

Answer 23

The phenyl group makes the drug an anti-convulsive.

Question 24

Explain barbiturate pharmacodynamics.

Answer 24

• onset 10-20 secs; lasts 8-20 mins
• constrict cerebral vasculature
• decreased cerebral oxygen
• lowers pain threshold (anti-analgesic)

Question 25

Thiopental and Methohexital effects on CV

Answer 25

• peripheral vasodilation (decrease in BP)
• Venous vasodilation; peripheral pooling, decreased venous return
• Vagolytic compensatory responses (HR and contractility increase)

Question 26

Barbiturate’s on Respiratory system

Answer 26

• Depression; decreasing response to CO2 and O2 –> could lead to increased rate to compensate
• Histamine release (not methohexital/only sulfur containing)

Question 27

Do barbiturates contain muscle relaxation or analgesia?

Answer 27

No; neither.

Question 28

The rate limiting step in Haem synthesis.

Answer 28

ALA synthetase

Question 29

Barbiturates + ALA synthetase =

Answer 29

Porphyrias leading to abdominal pain, psychosis, LMN palsies.

Question 30

What seems to be replacing barbiturates?

Answer 30

Propofol