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Anesthetics/Muscule Blockers/Muscle Relaxants
IUSM
51
Pharmacology
Professional
02/20/2015

Additional Pharmacology Flashcards

 


 

Cards

Term
thiopental

(class, mechanism, advantage/disadvantage, indication, contraindication, adverse effects, pharmacokinetics)
Definition
Class: general anesthetic, intravenous

Mechanism: enhance GABA(A) receptor activity; rapid onset, terminated by redistribution

Advantages: anti-seizure activity
Disadvantages: poor analgesia, little muscle relaxation

Indication: induction of anesthesia (rapid onset), neonates req. higher dose for induction

Contraindication: PORPHYRIA

Adverse effects: (decreased cerebral metabolism, decreased cerebral blood flow, decreased BP, depressed respiration)

Pharmacokinetics: CONTEXT-SENSTIVE HALF-LIFE, terminal half-life is substantially longer w/ continuous infusion
Term
propofol

(class, mechanism, advantage/disadvantage, indication, adverse effects, pharmacokinetics)
Definition
Class: intravenous general anesthetic

Mechanism: enhances GABA(A) receptor activity

Advantages: high degree of clearance (hepatic --> rapid recovery, less hangover than thiopental
Disadvantages: poor analgesia, slight muscle relaxation

Indication: induction or maintenance anesthesia

Adverse effects: (decreased cerebral metabolism, decreased cerebral blood flow, decreased BP, depressed respiration), PAIN AT INJECTION, ABUSE POTENTIAL (anesthesiology residents)'

Pharmacokinetics: redistribution plays are role in action duration and half-life
Term
etomidate

(class, mechanism, advantage/disadvantage, indication, adverse effects)
Definition
Class: intravenous general anesthetic

Mechanism: enhance GABA(A) receptor activity

Advantages: rapid onset, cardio stable (use for patients who have risks if hypotensive)
Disadvantage: poor analgesic

Indication: induction of anesthesia

Adverse effects: (decreased cerebral metabolism, decreased cerebral blood flow, depressed respiration), SIGNIFICANT NAUSEA/VOMITING, PROLONGED SUPPRESSION OF ADRENOCORTICAL STRESS RESPONSE (up to weeks post-operative)
Term
ketamine

(class, mechanism, advantage/disadvantage, indication, adverse effects, drug interaction)
Definition
Class: intravenous general anesthetic

Mechanism: blocks glutamate receptors

Advantages: increases BP, ANALGESIC, good for kids, amnesic dissociate state

Indication: alone for short procedures (maintenance), induction for longer procedures

Adverse effects: INCREASED cerebral blood flow, cataleptic state (muscle rigidity), emergence delirium (<16y/o usually), analog of PCP (hallucinogenic, abuse potential)

Drug interactions: potentiates affects of non-depolarizing muscle relaxants; w/ theophylline predisposes to seizures
Term
halothane

(IUSM know the adverse effects and pharmacokinetics)
Definition
Class: volatile general anesthetic

Advantage: bronchodilator, some skeletal muscle relaxation; VERY POTENT MAC 0.75%
Disadvantage: high blood/gas coefficient (slow induction), weak analgesic

Adverse effects: liver toxicity (due to metabolite), MALIGNANT HYPERTHERMIA (esp. this halogenated GA)

Pharmacokinetics: significant hepatic metabolism to trifluroacetylchloride (hepatotoxic)

Special: discontinued in US
Term
enflurane

(IUSM know the adverse effects)
Definition
Class: volatile general anesthetic

MAC 1.6%

Advantages: bronchodilator, significant skeletal muscle relaxation
Disadvantages: high blood/gas coefficient (slow induction)

Indication: induction (not much in US)

Adverse effect: SEIZURE ACTIVITY

Pharmacokinetics: 2-8% metabolized
Term
isoflurane

(class, advantage/disadvantage, MAC, indication, contraindication, adverse effects, pharmacokinetics)
Definition
Class: volatile general anesthetic

Advantage: low blood/gas coefficient, induction <10min, good muscle relaxant
Disadvantages: pungent odor (not used for induction b/c of this)

MAC 1.2%

Indication: maintenance of anesthesia

Contraindication: CHD

Adverse effects: DILATES CORONARY ARTERIES (CORONARY STEAL), malignant hyperthermia, general halogenated GAs

Pharmacokinetics: eliminated unchanged in exhalation (>99%)
Term
Adverse effects of halogenated volatile GAs
Definition
tachycardia, peripheral vasodilation, hypotension, concentration dependent depression of ventilation, dilates cerebral arteries w/ possible increase in intracranial pressure
Term
sevoflurane

(class, advantage/disadvantage, MAC, indication, adverse effect, pharmacokinetic)
Definition
Class: volatile general anesthetic

Advantage: low blood gas coefficient (0.65), rapid onset, rapid recovery, potent bronchodilator, direct relax of skeletal muscle, NO TACHYCARDIA
Disadvantage: expensive

MAC 2%

Indication: induction or maintenance of anesthesia; widely used for outpatient procedures and pediatrics

Adverse effects: PRODUCES NEPHROTOXIC COMPOUND A WITH RECIRCULATION, malignant hyperthermia, general halogenated GAs

Pharmacokinetics: 3% metabolized, organic fluoride as by-product
Term
desflurane

(class, advantage/disadvantage, MAC, indication, adverse effects, pharmacokinetics)
Definition
Class: volatile general anesthetic

Advatanges: LOWEST BLOOD/GAS COEFFICIENT (0.42), low fat solublility, very rapid onset, rapid changes and recovery (5-10min), bronchodilator, direct skeletal muscle relax
Disadvantages: not very potent, expensive

MAC 6%

Indication: outpatient surgeries, maintenance only of anesthesia

Adverse effects: COUGH/SALIVATION/BRONCHOSPASM when awaken, STRONG AIRWAY IRRITANT (not used for induction), produces CO with recirculation (so don't recirculate), malignant hyperthermia, general halogenated AEs

Pharmacokinetics: <1% metabolized
Term
methoxyflurane

(IUSM know the adverse effects)
Definition
Class: volatile general anesthetic

DETRIMENTAL TO KIDNEYS - 65% metabolized to FLUORIDE IONS that are nephrotoxic
Term
nitrous oxide

(class, advantage/disadvantage, MAC, indication, contraindication, adverse effects, pharmacokinetics)
Definition
Class: volatile general anesthetic

Advantages: insoluble, significant analgesia
Disadvantages: weak anesthetic and very low potency

MAC 105%

Indication: adjunct to other inhalation or intravenous anesthetic (NEVER ABOVE 80%)

Contraindication: PULMONARY HYPERTENSION

Adverse effects: BOWEL DISTENTION, PNEUMOTHORAX, INNER EAR PAIN, DIFFUSIONAL HYPOXIA (req. 100% post-operative), increased cerebral blood flow w/ potential increases in intracranial pressure

Pharmacokinetics: 99.9% eliminate unchanged in lungs
Term
order of nerves blocked for local anesthetics
Definition
pain (A-delta), autonomic C-fibers
cold
warmth
touch
deep pressure
motor
Term
use-depedendent block of local anesthetics
Definition
the greater the rate of nerve stimulation the greater the ability of the LA to block the VG-gated sodium channel
Term
what determines time to onset of local anesthetics
Definition
pka of drug
(pH of tissues determines drug access to intracellular compartment)
Term
what determines duration of local anesthetic
Definition
(contact time with nerve) affected by:
drug absorption (site of injection, dosage, adjunct)
drug distribution/redistribution (blood flow, ppb status, adjunct)
drug elimination (ester hydrlosis or amide metabolism by liver)
Term
metabolism of ester LA vs. amide LA
Definition
ester - plasma cholinesterase
amides - hepatic CYP450 system
Term
unique adverse effect of ester LAs
Definition
potential allergic reaction due to metabolite (para-amino benzoic acid)
Term
what determines the potency of a local anesthetic
Definition
lipid solubility
Term
patient characteristics of importance in local anesthetics
Definition
liver disease - don't use amides
low esterase activity - don't use esters
neonates - lower plasma proteins, higher sensitivity to drugs
pregnancy - drugs more effective (??why??)
patients w/ spinal cord disease - use in spine w/ caution, may be useful in fixed spinal cord injury
Term
uses of local anesthetics
Definition
1. local and regional anesthesia (topical, infiltration, intravenous)
2. peripheral nerve block
3. central nerve block
4. treatment of acute labor pain
5. analgesia in operative or post-op period
6. management of chronic pain (where local anesthetic may have prolonged effect)
7. aid in diagnosis and management prior to neurolytic procedures
Term
major adverse effects of anesthetics
Definition
1. CNS - stimulation (restlessness, tremor, convulsions), depression (drowsiness, sedation, respiratory failure)

2. CV - heart (dec. conduction/force of contraction/excitability), vascular smooth muscle relaxation (dec. BP)

3. Smooth muscle - decrease bowel and uterine contraction

4. hypersensitivity rxns - dermatitis, asthmatic attack

5. nausea - procaine 17%

6. methoglobinemia - prilocaine, benzocaine
Term
mechanism of action for local anesthetics
Definition
block VG-sodium channels from opening
block generation of an AP at post-synaptic cell
Term
lidocaine (anesthetic)

(class, features)
Definition
Class: local anesthetic, amide type
most popular
doses producing CNS toxicity cause cardiovascular depression
Term
etidocaine

(class, features)
Definition
Class: local anesthetic, amide type
BLOCKS MOTOR AND SENSORY ACTIVITY EQUALLY
Term
bupivacaine

(class, features)
Definition
Class: local anesthetic, amide type
more cardiotoxic than lidocaine
long-acting
levo-bupivacaine = s-enantiomer
Term
ropivacaine

(class, features)
Definition
Class: local anesthetic, amide type
less cardiotoxic than bupivacaine
long-acting
Term
prilocaine

(class, features)
Definition
Class: local anesthetic, amide type
methoglobinemia assoc.
Term
procaine

(class, features)
Definition
Class: local anesthetic, ester type
slow onset, short duration
metabolized to para-amino benzoic acid - potential allergic rxn
Term
cocaine

(class, features)
Definition
Class: local anesthetic, ester type
blocks NE (catecholamine) uptake
vasoconstrictor
abuse potential
used primarily in upper respiratory tract surgeries
Term
benzocaine

(class, features)
Definition
Class: local anesthetic, ester type
low sobulility (low potency)
MC topical agent
methemobglobinemia assoc.
Term
tetracaine

(class, features)
Definition
Class: local anesthetic, ester type
slower metabolism/more systemic toxicity assoc.
Term
topical local anesthetics
Definition
MC - benzocaine
cocaine - ear, nose, throat only
lidocaine
lidocaine/prilocaine mixture - for 5mm depth (bridge between topical and infiltrative)
Term
infiltrative local anesthetics
Definition
intradermal or subq injection
procaine - short duration
lidocaine - intermediate duration
bupivacaine - long duration
Term
intravenous local anesthetics
Definition
tourniquet-occluded limb (forearm and hand = MC)
lidocaine w/o epi is most frequent agent
Term
peripheral nerve block local anesthetics
Definition
onset determined by: proximity, cocnetration, volume and ionization of drug to nerve
lidocaine and bupivacaine MC
Term
central neural block local anesthetics
Definition
epidural or intrathecal
vasodilation from sympathetic blockade
BARICITY - determines direction of migration
lidocaine shorter than bupivacaine < tetracaine
Term
epidural agents
Definition
lidocaine, prilocaine, bupivacaine, ropivacaine
Term
spinal (intrathecal) agents
Definition
procaine, lidocaine, bupivacaine
Term
succinylcholine

(class, mechanism, onset, duration, elimination, special notes)
Definition
Class: neuromuscular blocker, depolarizing

Mechanism: binds nicotinic ACH receptors causing prolonged depolarization and paralysis; causes initial wave of fasciculation

Time to onset: 1-1.5 min
Duration: 5-8 minutes

Elimination: hydrolysis by plasma esterases

Cholinesterase inhibitor effects: early on intensify blockade, later reverse blockade

Phase I - endplate depolarized
Phase II - endplate partially repolarized
Term
d-Tubocurarine


(class, mechanism, duration, elimination)
Definition
Class: neuromuscular blocker, non-depolarizing, natural alkaloid

Mechanism: competitive antagonist at nicotinic receptor at NMJ; not orally active must be injected

Time to onset: 4-6min
Duration: 80-120min (long)

Elimination: renal elimination, liver clearance
Term
atracurium
Definition
Class: neuromuscular blocker, non-depolarizing

Mechanism: competitive antagonist at nicotinic receptor at NMJ, nor orally active must be injected

Duration: 30-60 (intermediate)

Elimination: Hoffman, hydrolysis by esterases
Term
pancuronium
Definition
Class: neuromuscular blocker, non-depolarizing

Mechanism: competitive antagonist at nicotinic receptor at NMJ, nor orally active must be injected

Duration: 80-100min (long)

Elimination: renal elimination
Term
rocuronium
Definition
Class: neuromuscular blocker, non-depolarizing

Mechanism: competitive antagonist at nicotinic receptor at NMJ, nor orally active must be injected

Duration: 30-60min (intermediate)

Elimination: liver metabolism
Term
verucronium
Definition
Class: neuromuscular blocker, non-depolarizing

Mechanism: competitive antagonist at nicotinic receptor at NMJ, nor orally active must be injected

Duration: 60-90min (intermediate)

Elimination: liver metabolism, renal elimination
Term
non-depolarizing neuromuscular blocker adverse effects
Definition
GANGLION BLOCKADE: decreased BP (d-TC > pan > atra/veru)
HISTAMINE RELEASE: decreased BP, bronchospasms, increased secretions (d-TC > atra >> pan/roc/veru)
MUSCARINIC BLOCKADE: tachycardia (pan and veru)
Term
depolarizing neuromuscular blocker adverse effects
Definition
fsciculations
myalgia
hyperkalemia --> cardiac arrhythmias (esp. burn pts and soft-tissue injuries in paraplegics)
prolonged paralysis with atypical peudocholinesterase activity
MALIGNANT HYPERTHERMIA
Term
uses of neuromuscular blocker
Definition
major: surgical paralysis (NO ANALGESIC EFFECTS)
Term
sequence of paralysis in neuromuscular blockers
Definition
1. muscles of fine movement (fingers, eyes, jaw, larynx)
2. limbs
3. trunk
4. intercostal muscles
5. diaphragm - recovers first, breathing recovers first
Term
baclofen

(class, mechanism, indication, adverse effects, pharmacokinetics)
Definition
Class: skeletal muscle relaxant

Mechanism: GABA(A) receptor agonist, spinal cord action to prevent excitation to motor neurons presynpatically, maybe supraspinal CNS action

Indicatoin: spasticity asocc. w/ MS/spinal cord injury or disease; trigeminal neuralgia

Adverse effects: DROWSINESS, dizziness, lightheadedness, confusion, muscle weakness

Pharmacokinetics: oral and intrathecal admin, renal elimination
Term
dantrolene


(class, mechanism, indication, adverse effects, pharmacokinetics)
Definition
Class: skeletal muscle relaxant

Mechanism: inhibits calcium release from SR in muscles

Indication: malignant hyperthermia (reduce mortality from 80% to <10%)

Adverse effects: muscle weakness

Pharmacokinetics: oral or IV admin, hepatic metabolism
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