Anesthetic Drugs

Front 1

Why does Propofol sting?

Back 1

Preservative metabisulfite (allergen to some?) or Benzyl alcohol.
Avoid stinging with 5% lido 1% propofol 1:1 ratio.

Front 2

How is Propofol metabolized

Back 2

Liver. Lungs (up to 30%)
Inactive metabolites secreted though kidneys. Quickly redistributes.

Front 3

Propofol dosing and half life

Back 3

induction 1.5-2.5 mg/kg IV
(2.5-3.5 mg/kg IV kids)
25-75 mcg/kg/min MAC
100-200 mcg/kg/min TIVA
T1/2 alpha 2-4 min
T1/2 B 4-23 hours
Pt awakes in 3-10 minutes after induction dose.
97% protein bound

Front 4

Propofol mechanism of action

Back 4

Presumed potentiation of Cl current of GABA receptor complex : AKA hyperpolarizes the Reticular Activating system.

Front 5

Propofol CNS effects

Back 5

Decreases CBF, ICP, and CRMO2 (cerebral metabolic rate of O2 consumption.
Can decrease CPP due to reduced MAP.
Occasional twitching noted on induction.

Front 6

Propofol Cardiovascular effects.

Back 6

Decrease in SBP due to vasodilation (both arterial and venous).

Decreases Preload and Afterload.

Inhibits barroreflex response.

mild HR increase

Occasional profound bradycardia or asystole.

Front 7

Propofol Respiratory effects.

Back 7

Depresses respirations

Reduces TV and rate

reduced hypoxic drive/ Hypercapnic drive.

Less wheezing comp to pentathol.

Front 8

Propofol infusion syndrome

Back 8

Unexplained tachycardia after dosing .
It can lead to cardiac failure, rhabdomyolysis, metabolic acidosis and renal failure and is often fatal

Check ABG for Metabolic acidosis.

Front 9

Barbituates acidic or alkalitic?

Back 9

Alkaline: pH >10
Will precipitate in acidic solution.

Front 10

Barbituate metabolism

Back 10

Hepatic oxidation
(except phenobarbitol which is excreted unchanged in the urine)
Can conjugate and be excreted in the bile.

Front 11

Contraindications for barbituates:

Back 11

AIP (acute intermittant porphyria) Barbituates increase porphyrin production through stimulation of aminolevulinic acid synthetase.

Front 12

Barbituate examples and induction doses

Back 12

Thiopental 3-5 mg/kg
Methohexital 1-1.5 mg/kg.
20-30 mg/kg PR in mentally challenged or pediatric patients.

Front 13

Barbituate mechanism of action

Back 13

1: Enhances inhibitory neurotransmission (GABBA mediated?)

2: Inhibits excitatory transmission

Front 14

Barbituate CNS activity

Back 14

Potent cerebral vasoconstrictor, decreases CBF, Blood volume, ICP and CMRO2.
Preferred for space occupying lesions. Good for temporary clip on an artery.
Neuroprotective from focal (not global ischemia)
Will activatic epileptic foci, which can facilitate their identification during ablation surgury or ECT.

Front 15

Barbituate cardiovascular effect

Back 15

Modest decrease in SBP due to peripheral vasodilation.
Blunts baroreflex but compensatory tachcaredia limits drop in BP.

Decrease in C.O. (blood pooling)

Negative Inotrope.

Front 16

Barbiturate Respiratory effects:

Back 16

Resp. Depressant

Decreases minute ventilation by decreaasing TV and Rate.

Decrease response to hypoxia and hypercarbia,

Only mild suppression of laryngeal reflexes

Front 17

Barbituate Side effects

Back 17

Don't inject intra-arterial

Barbituate crystals may occlude small arteries.

SQ injection = irritation

histamine release.

Front 18

Barbituate indication

Back 18

Induce anesthesia, Treat ICP

Front 19

Benzodiazepine routes of absorption

Back 19

IM,IV,Oral, intranasal,, sublingual

Front 20

Benzodiazepine pharmacokinetics

Back 20

Highly lipid-soluable.

Metabolized by liver via microsomal oxidation or glucuronide conjugation.

Diazapam has active metabolites

Versed metabolize by CYP 450 to single inactive metabolite

versed short context-sensitive half-life make it the only suitable on e for continuous infusion.

Front 21

Benzodiazepine pharmacodynamics

Back 21

Activate GABA receptor complex and enhancement of GABA-mediated chloride currents. =hyperpolarization of neurons and dreduced excitability.

Versed affinity for these sites is 2x that of valium.

Sedative-hypnotic effects and amnestic properties via gamma subunits.

Anticonvulsant. ( alpha subunit property)

Limited respiratory depression when given alone.

Front 22

Benzodiazepine CNS effect

Back 22

Decreases CMRO2 and CBF

Has a cieling effect: cannot produce isoelectirc EEG

Little effect on ICP

NOT neuroprotective.

Potent anticonvulsant. (epilepsy, ETOH withdrawal, Local anesthetic induced seizure.)

Front 23

Benzodiazepine Cardiovascular effects

Back 23

Can reduce BP (Versed> valuium)

Effects of hypotenstion are exaggerated in hypovolemic patients.

Front 24

Benzodiazepine Respiratory effects.

Back 24

minimal depresion

Transient apnea after induction ( esp. with opioids)

Decreases ventilatory response to CO2

Front 25

Benzodiazepine side effects

Back 25

Allergic reactions rare.

Valium contains propylene glycol: Painful on injection.

Front 26

how do you recognize if a drug is a Benzodiazepine
Give 2 examples

Back 26

-PAM
-LAM

Midazolam (versed)
Lorazapam

Front 27

Benzodiazepine doses

Back 27

Versed 1-2 mg IV

0.5 mg/kg Oral for Kids 30 prior to surgury

Induction: Versed 0.1-0.3
mg/kg

Antiepileptic: Valum 0.1 mg/kg/IV

Front 28

Ketamine effects

Back 28

Potent Analgesic,
Dissociative anesthesia
(eyes remain open with slow nystagmic gaze or cateleptic state)

Front 29

Ketamine pharmicokinetics

Back 29

Lipid soluable. Racemic mixure
S(+) isomoer more potent that R(-) isomer

Redistributed to inactive tissue sites.

Metabolized by CYP450

Norketamine 1/3 as potent metabolie

Low protein binding. (12%)

NMDA receptor complex inhibition

Lacrimeation and salivation are increased cocomitantly administer anticholinergic)

Front 30

Ketamine CNS effects

Back 30

Do NOT give with elevated ICP
or intracranial pathology.

May help treat epilepsy.

Nightmares. (decreased with benzos)

Front 31

Ketamine Cardiovascular effects

Back 31

transient increases in BP, HR, C.O. from centrally mediated sympathetic stimulation.

Direct myocardial depressant, usually masked by SNA stimulation.

Front 32

Ketamine Respiratory effects

Back 32

Hypoventialtion may follow induction.

relaxes bronchial smooth muscle and may help in reactive airways.

Front 33

Ketamine routes, doses

Back 33

IV IM Oral Pr Epidural

induction 1-2 mg/kg IV
4-6 mg/kg IM

Regional anesthesia 0.2-0.8 mg/kg IV.

Front 34

Etomidate Indications

Back 34

Induction for cardiac patients. use when pt has - cardiac contractility.

Front 35

Etomidate Pharmicokinetics

Back 35

Ester hydrolysis to inactive metabolites.

GABA-like effects Potentiates GABA -mediated chloride currents.

Front 36

Etomidate CNS effects

Back 36

Potent cerebral vasoconstrictor
DO NOT GIVE FOR CRANIOTOMIES. decreaes CBF and ICP
not neuroprotective, may activate seizure foci.

Front 37

Etomidate
Cardiovascular effects

Back 37

Some SBP decreases
Minimal changes in HR and C.O.

Front 38

Etomidate endocrine effects

Back 38

Cuses adrenocortical supression by producing dose-dependent innhibition of 11B-hydorxylase, and enzyme that converts cholesterol to cortisol. Probably don't need stress dose of steroids. Thus ok for induction, not for infusion

Front 39

Etomidate clinical uses

Back 39

used for compromized cardiac contractility.

Front 40

Etomidate Induction dose

Back 40

0.2-0.3 mg/kg iv
(onset similar to Propofol.
Most find it painful upon injection.

Front 41

Etomidate side effects

Back 41

up to 80% myoclonic movments reported.
Post op N/V "pukidate"

Front 42

Dexmedetomidine "precedex" mechanism of action

Back 42

Highly selective alpha-2 adrenergic agonist. (yohimbine and phentolamin are alpha-2 antagonists that can compete)

Produces Hypnosis through stimulation fo Alpha-2 recptors in Locus ceruleus

Resembles natural sleep by activating endogenous sleep pathways.
Is analgesic at spinal chord with no depression of respiration.

Front 43

Dexmedetomidine clearance

Back 43

Metabolites excreted through urine and bile, short elimination half-time
context sensitive half-life increase from 4 minutes (after 10 minute infusion) to 250 minutes (after 8 hour infusion)

Front 44

Dexmedetomidine neural effects

Back 44

Decreases CBF without changes in ICP or CMRO2

Potential fo rtolerance and dependence.

Front 45

Dexmedetomidine cardiovascular effects

Back 45

moderate decreases in HR and SVR (thus BP)

Bolus transientsly increases BP and decreases HR)

Bradycardia to Asystole documented.

Front 46

Dexmedetomidine Respiratory effects

Back 46

small drop in TV.
Little depressant, good for anesthesia.

Front 47

Dexmedetomidine Uses

Back 47

Short term sedation (ie Fiberoptic intubations, deep brain stimulation, etc.)

Front 48

Dexmedetomidine doses

Back 48

Loading dose 0.5-1mcg/kg Iv loading dose over 10 minutes then 0.2-0.7 mcg/kg/hr.