Anesthetic Pharmacology 1

Question 1

GA
RA
MAC
SAC

Answer 1

General blocks normal nociception distal from site of injury

Regional at or near site of injury

Monitored anesthesia care - level that requires creful monitoring

Not considered anesthesia and can be administered by non-anesthesiologists in different setting (sedation/analgiesia)

Question 2

How anesthesia blocks
Motor reflexes
Pain and suffering
Autnomic reflexes

Answer 2

Akinesia
Analgesia and hypnosis
Autonomic stabilization

Question 3

Balanced anesthesia

Answer 3

Several different agents used to maximize benefits of each agent

Question 4

IV agents

Answer 4

Hypnotic/sedative
Opitates
Paralytics

Question 5

IV agent features

Answer 5

Lipid soluble that cross BBB

Rapid onset to reduce anxieety and slow delays

Question 6

Barbituates

Answer 6

Anhydrous sodium salts
Require reconstitution
pH>10
May precipitate qwith acidic

Accidental arterial injection results in thromboembolic complications

Question 7

Mech of action of Barbituates

Answer 7

GABA-A channel agonists

Activates CNS Cl- channels…results in enhancment of both inhibitory NT and inhibition of excitatory transmission

Question 8

Redistribtuion of barbitituates

Answer 8

Clinical effect terminated as moved from brain to lean tissues and fat

Hangover from slow elimination through metabolism

Question 9

Metab of barbituates

Answer 9

Hepatic
Metabolites inactive (exceted in bile and urine)
Affect by CYP inducers
Increase production of porphyrins…contraindicated in patients with acute intermittent porphyria

Question 10

Physio effects of barbituates

Answer 10

Rapid onset and awakening
May result in hypotension (vasodilation (Veno) and myocardial depression…blunts baroreceptor reflex but tachycardia will occur)
Significant resp depression (apnea common)
Decreased cerebral metabolic rate, CBF, and ICP

Question 11

Benzodiazepines

Answer 11

Not normally as IV anesthesia

Most common preop anxiolysis
Potent amnestic agents (Lorazepam will produce hsort term retorgrade…rest as anterograde)
Lipid soluble and protein bound (albumin)(accounts for rapid onset)

Redistributed

Question 12

Benzos used for anesthesiology and others

Answer 12

Midazolam
Lorazepam

Diazepam
Alprazolam
Oxazepam

Question 13

Mech of action benzos

Answer 13

GABA receptor activation (gamma subunit)

Question 14

Metab of benzos

Answer 14

Microsomal oxidation (midazolam and diazepam)

Glucuronide conjugation (lorazepam)

Diazepam oxidized to 2 major metabolites that may prolong effect

Midazolam into 1 inactive mtabolite

Question 15

Physio effects of benzos

Answer 15

Vraible onset

Mild to moderate hypotension (vasodilation (Veno) but minimal myocardial depression)

ignifanct resp depression (apnea common)

Decreased in CMRO2, CBF, and ICP are agent dependent

Question 16

Propofol

Answer 16

Agent of choice for IV anesthesia

Very rapid onset and rapid termination due to redistribtuion

May be used for general, MAC and sedation in OR, ICU or other procedral areas

Question 17

Propofol solubility

Answer 17

Insoluble in aqueous

Formulated as emulsion with soybean oil, glycerol, egg yokl lecithin

Some promote bacterial grwot

Question 18

Propofol mech

Answer 18

GABA activator in CNS

Terminated by redistribtuion
Very high plasma clearance explains lack of hangover compared to thiopental

Rapid hepatic metabolism to inactive metabolites that are excreted through kidney s

Question 19

Propofol physiologic and other effects

Answer 19

Hypotension (vasodilation, myocardial depression, blunting of baroreceptor, abolished reflexive tachycardia)

Significant resp depression (apnea requiring vewntilator)

Reduces CMRo2, CBF, and ICP

Pain on injection

No analgesic or anxiolytic effect

Reduces risk of PONV and can be used to tx PONV

Question 20

Etomidate

Answer 20

Hemodynamically stable

Rapid loss of consciousness
Little anxiolysis and no analgesia

Carboxylated imidazole that is insoluble

Supplied in propylene glycol mix

Question 21

Etomidate Mech

Answer 21

Rapid onset

Lipid soluble

GABA a chloride channel efect

Recovery dependent on redistribtuion

Metabolized via plasam ester hydrolysis to inactive metabolites excreted in urine and bile

Question 22

Physio effects of etomidate

Answer 22

CV stability after bolus

Moderate resp depression

Question 23

CNS effects of etomidate

Answer 23

Reduces CBF and CMRO2

Produce excitatory spikes on EEG

May activate pre-existing seizure foci

Spontaneous myoclonic activity

Question 24

Other effects of edomidate

Answer 24

Increase risk of PONV

Associated with pain

Associated with adrenocortical suppression (inhibtion of 11beta-hydroxylase needed to convert cholesterol to cortisol)

Question 25

Ketamine including mech

Answer 25

Dissociative anesthesia

Different from hypnosis

Brain remains active but disconnected from normal reality

Anatagosim of NMDA receptor

Question 26

KEtamine structure and metabolized

Answer 26

Partially H20 soluble and hihgly lipid soluble

Low protein binding

Terminated by redistribtuion

Metabolized by N-demethylation in the liver…active metabolite less potent and metabolized to inactive that are excreted in urine

Question 27

Clinical effects of ketamine

Answer 27

Patients do not fall asleep

Reflexes partially preserved (airway reflex response variable)

Eyes may remain open with nystagmus

Lacrimation and salivation

Question 28

Emergence reactions

Answer 28

Nightmares
Fear and confuusion

Less in children

Question 29

Clinical effects of ketamine

Answer 29

Increase CBF, CMRO2 and ICP

Contraindicated with intracranila pathology

Reduces risk of seizures and can be used to terminate status epilepticus

Myocardial depressant

Increased BP, HR, and CO (symp stimulation and NE surge from adrenals)

Not associated wiht resp depression (relaxes bronchial smooth muscle)

Question 30

4 components of anesteisa

Answer 30

Amensia, akinesia, analgesia, hypnosis