Anesthetic Drugs Flashcards Preview

STEP 1 > Anesthetic Drugs > Flashcards

Flashcards in Anesthetic Drugs Deck (35)
1

How does lipid solubility impact anesthesia

CNS drugs must be lipid soluble (cross the BBB) or be actively transported

drugs with low solubility in blood = rapid induction and recovery times
drugs with high solubility in lipids = increased potency = 1/MAC

2

What is MAC?

minimal alveolar concentration required to prevent 50% of subjects from moving in response to noxious stimulus

3

Inhaled anesthetic examples

N2O has decreased blood and lipid solubility and thus fast induction and low potency
Halothane has high lipid and blood solubility and thus high potency and slow induction

4

Name the inhaled anesthetics

halothan, enflurance, isoflurance, sevoflurane, methoxyflurane, N2O

5

Effects of inhaled anesthetics

myocardial depression
respiratory depression
nausea/emesis
increased cerebral blood flow (decreased cerebral metabolic demand)

6

Toxicity of halothane

hepatotoxicity

7

Toxicity of methoxyflurane

nephrotoxicity

8

Toxicity of enflurane

proconvulsant

9

Toxicity of N2O

expansion of trapped gas in body cavity (not good for GI surgeries)

10

What is malignant hypertermia?

rare, life-threatening hereditary condition in which inhaled anesthetics and succinylcholine induce fever and severe muscle contractions (can see cyanotic skin mottling)

Tx: dantrolene

11

Properties of barbiturates as IV anesthetic

thiopental - high potency, high lipid solubility, rapid entry into brain

12

Use of barbiturate for IV anesthetic

induction of anesthesia and short surgical procedures
effect terminated by rapid redistribution into tissue and fat
decreased cerebral blood flow

13

Use of benzos for IV anesthetic

midazolam for endoscopy
adjunctively with gaseous anesthetics and narcotics

14

Effects of benzos for IV anesthetic

may cause severe postoperative respiratory depression, decreased BP (tx with flumazenil), anterograde amnesia

15

Mechanism of ketamine for IV anesthetic

PCP analogs that acts as dissociative anesthetics
blocks NMDA receptors

16

Effects of ketamine for IV anesthetic

cardiovascular stimulants
cause disorientation, hallucination, bad dreams
increase cerebral blood flow

17

Use of propofol for IV anesthetic

sedation in ICU, rapid anesthesia induction, short procedures
less postoperative nausea than thiopental
potentials GABAa

18

Name the local ester anesthetics

procaine, cocaine, tetracaine (one I)

19

Name the local amide anesthetics

lidocaine, mepivacaine, bupivacaine (two I)

20

Mechanism of local anesthetics

block Na+ channels by binding to specific receptors on inner portion of channel
bind to activated Na+ channels so most effective in rapidly firing neurons
3 degree amine local anesthetics penetrate membrane in uncharged form, then bind ion channels as charged form

21

Use of local anesthetics

minor surgical procedures, spinal anesthesia

if allergic to esters give amides

22

Toxicity of local anesthetics

CNS excitation, severe cardiovascular toxicity (bupivicaine), HTN, hypotension, arrhythmias (cocaine), methemoglobinemia (benzocaine)

23

Use of neuromuscular blocking drugs

muscle paralysis in surgery or mechanical ventilation
selective for motor (vs. autonomic) nicotinic receptors

24

Name the depolarizing agent and mechanism

succinylcholine
strong ACh receptor agonist
produces a sustained depolarization and prevents muscle contraction

25

Reversal of succinylcholine blockade

phase I - prolonged depolarization - NO ANTIDOTE
- the block is potentiated by AChE inhibitors

phase II - repolarized but blocked - ACH receptors are available but desensitized - ANTIDOTE is AChE inhibitors

26

Complications of succinylcholine

hypercalcemia, hyperkalemia, malignant hyperthermia

27

Name the nondepolarizing agents

tubocurarine, atracurium, mivacurium, pancuronium, vecuronium, rocuronium

28

Mechanism of nondepolarizing agents

competitive antagonists - compete with ACh for receptors

29

Reversal of nondepolarizing blockade

neostigmine (must be given with atropine to prevent muscarinic effects such as bradycardia), edrophonium, and other cholinesterase inhibitors

30

Mechanism of dantrolene

prevents release of Ca2+ from sarcoplasmic reticulum of skeletal muscle

31

Use of dantrolene

malignant hypertermia and neuroleptic malignant syndrome (toxicity of antipsychotic drugs)

32

Mechanism of baclofen

activates GABAb receptors at spinal cord level, inducing skeletal muscle relaxation

33

Use of baclofen

muscle spasms (e.g. acute low back pain)

34

Mechanism of cyclobenzaprine

centrally acting skeletal muscle relaxant
structurally related to TCAs, similar anticholinergic side effects

35

Use of cyclobenzaprine

muscle spasms