anesthetic drugs Flashcards
CNS drugs must ….(according to structure_
- be lipid soluble (cross BBB)
or 2. be actively transported
anesthetic drugs - solubility in blood / lipids
low solubility in blood –> rapid induction and recovery times
increased solubility in lipids –> increased potency
inhaled anesthetics - MAC? (definition)
minimal alveolar concentration (of inhaled anesthetic) required to prevent 50% of subjects from moving in response to noxious stimulus (e.g. skin incision)
potency vs minimal alveolar concentration (EQUATION)
potency = 1 / MAC
example of inhaled anesthetic with low blood and lipid solubility
nitrous oxide
example of inhaled anesthetic with increased blood and lipid solubility
halothane
inhaled anesthetic with increased blood and lipid solubility –> …. (potency and induction)
high potency
low induction
inhaled anesthetic with low blood and lipid solubility –> …. (potency and induction)
low potency
high induction
inhaled anesthetics - drugs
(HALOTHANE, -FLURANE, N20)
- halothane 2. enflurane 3. isoflurane
- sevoflurane 5. methoxyflurane
- nitrous oxide (N2O) 7. desflurane
inhaled anesthetics - mechanism of action
unknown
inhaled anesthetics - side effects (and which drug) and other effects
- fulminant hepatic necrosis (halothane)
- nephrotoxicity (methoxyflurane)
- proconvulsant (enflurane)
- expansion of trapped gas in body cavity (N20)
- malignant hyperthermia (all)
- Myocardial and resp depression
- nausea/emesis
- increased cerrebral blood flow (decreased metabolic demands)
malignant hyperthermia - definition/causes/manifestation ….
rare, life threatening condition in which inhaled anesthetics or succinylcholine induce fever and severe muscle contraction
malignant hyperthermia - manifestations / susceptibility
fever and severe muscle contraction
Susceptibility is AD with variable expression –> mutation in voltage-sensitive ryanodine receptor cause increase Ca+ release from sarcoplasmic reticulum
malignant hyperthermia - treatment
dantrolene
Intravenous anesthetics - groups/drugs?
- barbiturates - thiopental
- benzodiazepines - midazolam
- arylcyclohexylamines - ketamine
- opioids - morphine, fentanyl
- propofol
Intravenous anesthetics - thiopental - properties
high potency, high lipid solubility, rapid entry BBB
Intravenous anesthetics - thiopental - clinical uses
induction of anesthesia and and short surgical procedures
Intravenous anesthetics - thiopental’s effect terminated by
rapid redistribution into tissue and fat
Intravenous anesthetics - thiopental - side effects
decreases cerebral flow
Intravenous anesthetics - benzodiazepines - drugs?
midazolam
Intravenous anesthetics - midazolam - clinical uses
- MC drug used for endoscopy
2. adjunctively with gaseous anesthetics and narcotics
Intravenous anesthetics - midazolam - side effects
- severe postoperative respiratory depression
- low BP
- anterograde amnesia
Intravenous anesthetics - treat midazolam overdose with
flumazenil
Intravenous anesthetics - arylcyclohexylamines - drugs
ketamine
Intravenous anesthetics - ketamine - mechanism of action
PCP analog that act as a dissociative anesthetics
Block NMDA receptors
cardiovascular stimulant
Intravenous anesthetics - ketamine - side effects
- hallucination
- bad dreams
- disorientation
Intravenous anesthetics - ketamine - except its action an anesthetic is also a
cardivascular stimulant –> useful for patients in cardiogenic of septic shock
Intravenous anesthetics - ketamine effect on cerebral arteries
increase cerebral blood flow
Intravenous anesthetics - opioids - drugs
- morphine
2. fentanyl
Intravenous anesthetics - opioids - clinical use
uses with other CNS depressants during general anesthesia
Intravenous anesthetics - propofol - mechanism of action
potentiates GABA-A
Intravenous anesthetics - propofol - side effects
- low BP
2. chemical pancreatitis
Intravenous anesthetics - propofol vs thiopental according side effects
propofol –> less postoperative nausea
Intravenous anesthetics - propofol clinical use
- used for sedation in ICU
- rapid anesthesia induction
- short procedures
malignant hyperthermia - treatment
dantrolene
Intravenous anesthetics - groups/drugs?
- barbiturates - thiopental
- benzodiazepines - midazolam
- arylcyclohexylamines - ketamine
- opioids - morphine, fentanyl
- propofol
local anesthetics - groups
- esters
2. amides
local anesthetics - groups/drugs
- CAINE
1. esters –> procaine, cocaine, trtracaine, benzocaine
2. amides –> lidocaine, mepivacaine, bupvacaine (AMIDES HAVE 2 Is in name)
local anesthetics - mechanism of action
- block Na+ channels by binding to specific receptors on inner portion of channel. Preferentially bind to activated Na+ channels, so must effective in rapidly firing neurons.
- They penetrate membrane in uncharged form, then bind to ion channels as charged form (3ry amines)
local anesthetics - clinical use
- minor surgical procedure
2. spinal anesthesia
local anesthetics - toxicity (and which drugs)
- CNS excitation
- severe cardiovascular toxicity (bupivacaine)
- hypertension 4. hypotension
- arrhythmias (cocaine)
- methemoglobinemia (benzocaine)
IF ALLERGIC TO TO ESTERS –> GIVE AMIDES
local anesthetics can be given with … (why)
vasoconstrictors (usually epinephrine) to enchance local action - decrease bleeding, increase anesthesia by decrease systemic concentration
local anesthetics in infected (acidic) tissue
alkaline anesthetics are charged and cannot penetrate membrane effectively –> need more anesthetic
local anesthetics - order of nerve predominates
small myelinated fibers > small unmyelinated fibers > large myelinated fibers > large unmyelinated fibers
local anesthetics - order sensation loss
- pain 2. temperature 3. touch 4. pressure
local anesthetics - groups/drugs
- CAINE
1. esters –> procaine, cocaine, trtracaine, benzocaine
2. amides –> lidocaine, mepivacaine, bupvacaine
neuromuscular blocking drugs - purpose
muscle paralysis in surgery or mechanical ventilation
neuromuscular blocking drugs - muscle paralysis in
surgery or mechanical ventilation
neuromuscular blocking drugs - selective for
motor (vs autonomic) nicotinic receptors
neuromuscular blocking drugs - receptors
motor nicotinic receptors
- selective for motor (vs autonomic) nicotinic receptors
neuromuscular blocking drugs are divided to (and drugs)
- depolarizing –> succinylcholine
- nondepolarizing –> (-CURARINE, -CURIUM, -CURONIUM)
- Tubocurarine 2. Atracurium 3. Mivacurium
- Pancurorium 5. Vecuronium 6.Rocuronium
neuromuscular blocking drugs - depolarizing - drugs
succinylcholine
succinylcholine - mechanism of action
strong ACh receptor agonist –> produce sustained depolarization and prevents muscle contraction
succinylcholine - complications
- hypercalcemia
- hyperkalemia
- malignant hyperthermia
depolarizing neuromuscular blockage - phases and characteristic
phase I - prolonged depolarization
phase II - repolarized but blocked. ACh receptros are available but desensitized
depolarizing neuromuscular blockage - phase II - receptor’s condition
ACh receptros are available but desensitized
depolarizing neuromuscular blockage - reversal of blockage by … (antidote?)
phase I –> no antidote
phase II –> cholinestarase inhibitor
depolarizing neuromuscular blockage - action of cholinestarase inhibitor
phase I –> potentiates the block
pase II –> antidote
nondepolarizing neuromuscular blockage - drugs?
(-CURARINE, -CURIUM, -CURONIUM)
- Tubocurarine 2. Atracurium 3. Mivacurium
- Pancurorium 5. Vecuronium 6.Rocuronium
nondepolarizing neuromuscular blockage - mechanism of action
competitive antagonists - compete with ACh for receptors
nondepolarizing neuromuscular blockage - reversal of blockage?
cholinesterase inhibitors
- edrophonium
- neostigmine (with atropine)
- other cholinesterase inhibitors drugs
nondepolarizing neuromuscular blockage - reversal of blockage - neostigmine featrues
must be given with atropine to prevent muscarinic effects such as bradycardia
dantrolene - mechanism of action
prevents release of Ca2+ from the sarcoplasmic reticulum of skeletal muscle
dantrolene - clinical use
- malignant hyperthermia
2. neuroleptic malignant syndrome (a toxicity of antipsychotic drugs)
Baclofen - mechanism of action
Activate GABA -B receptors at spinal cord level –> induces skeletal muscle relaxation
Baclofen - clinical use
muscle spasms (eg. acute low back pain)
cyclobenzaprine - mechanism of action
centrally acting skeletal muscle relaxant
structural related to TCAs
cyclobenzaprine - clinical use
muscle spasm
cyclobenzaprine is stractural related to
TCAs
cyclobenzaprine - side effects
similar to anticholinergic side effects
neuroleptic malignant syndrome is a toxicity of
antipsychotic drugs
Intravenous anesthetics - groups/drugs?
- barbiturates - thiopental
- benzodiazepines - midazolam
- arylcyclohexylamines - ketamine
- opioids - morphine, fentanyl
- propofol
local anesthetics - groups/drugs
- CAINE
1. esters –> procaine, cocaine, trtracaine, benzocaine
2. amides –> lidocaine, mepivacaine, bupvacaine
inhaled anesthetics - drugs
(HALOTHANE, -FLURANE, N20)
- halothane 2. enflurane 3. isoflurane
- sevoflurane 5. methoxyflurane
- nitrous oxide (N2O) 7. desflurane