PDA Anesthetics nad introductions Flashcards
What are the unique side effects of propofol?
pain on injection, and often given with lidocaine
can cause initial excitation on induction
What do you do for patients who are at risk for hypotension for anesthesia?
utilize Etomidate
What are the unique side effects of Etomidate?
high incidence of pain on ijection, myoclonus
significant nausea
suppresion of adrenocorticol response to stress; can cause increased death
What type of anesthesia does ketamine produce??
Dissociative anesthesia
- profound analgesia
- eyes open but pts unresponsive
- amnesia
- bronchodilator
What are some of the unique side effects of ketamine?
emergence delilrium nystagmus, salvitation, spontaneous movement lacrimation increased ICP hypertension
What is ketamine reseved for?
ppatients with bronchospasm
children undergoing short painful procedures
What is midazolam used for?
short acting benzo; GABAa activator
used alone for concious sedation
What are midazolam side effects?
respiratory depression; arrests
caution in pts with neuromusc diseases
hypotension
What are some commonalities of inhalation general anesthetics?
very low therapeutic indices; LD50/ED50 very low;
vaporized or gas; uniqeu and important pharmokinetics
What are the role of partition coefficients used for?
determine relative amount of anasthetics in different compartments
How are anesthesia eliminated?
gas moves from blood into inspired air; fat and high solubility into fat changes recovery
Why isn’t Isoflurane used to induce anesthesia?
Coughing, and respiratory irritant
What is the risk of toxicity with MAO inhibitors related to food intake?
Tyramine build up due to MAO inhibition leads to hypertensive crisis due to Tyramine causing NE release
What are the therapeutic uses of MAO inhibitors
second line depressive disorder treatment
Narcolepsy
What are the central criteria of Schizophrenia?
two symptoms at least one must be postiive
What are the positive symtpoms of schizophrenia?
Delusions, hallucination, disorganized speech
What are the negative symptoms of schizophrenia?
groslly disorganized or catatonic behavior, blunted affect, lack of spontaneity, poor abstract htinking, poverty of thought, social withdrawal
What is the dopamine hypothesis of schizophrenia?
schiz results from hyperactivity of dopaminergic neruons or their receptors; based on the fact that all effective antipsychotics interact with dopamine systems
What antipsychotic has cardiac effects?
Thioridazine
What was the first drug of anti-psychotics to go onto the market?
Clozapine
What are the negative side effects of clozapine?
lowers seizure thresholds and can cause agranuloctyosis
What atypical antipsychotic has a shorter half life and is sued for augmentation of depression?
Quetiapine
What are the uses of the antipsychotic drugs?
actue psychotic episodes chronic schizophrenia manic episodes, bipolar schizoaffective disorder augmentation in depression Tourette's, antiemisis
What antipsychotic is not sued to treat emesis?
thioridazine
What was the first drug used to treat bipolar?
lithium blocks manic behavior; has no behavior change in normals
What is the mechanism of aciton of bipolar disorder?
Inhibitis pohosphatase conversion of IP2 to IP1
Pharmokinetics of liuthium?
complete abs in 6 to 8 hous serum half life 18–24 hours, unboundt o plasma protein, CSF concentration half of plasma concentration renal eliminated
What is the difference between half life of lithium in elderly vs young?
Lithium half life is much longer in elderly 30-36 h;ours compared to 18-24 hours
What can raise Lithium levels?
increase Na excretion such as by loop diuretic
also ACE inhibitors lead to increase Lithium levels
Side effects?
fatigue, muscle weakness, tremor, Gi symptoms, slurred speech. Coma and dangerous side effects at 2-3x tx levels
Alternates to lithium?
Carbamazepine and Valproic acid, Olanzapine and fluoxetine combined, initial control is with haloperidol in ER of manic episodes
What is mechanism of action of Carbamazepine?
blocks sodium channels
What is mechanism of Valproic acid?
blcoks repetitive neuronal firing
reduce T-type C++ current
increase GABA concentration
Characteristics of Generalized anxiety disorder?
persistent anxiety for at least 1 month duration, absence of specific symptoms of other disorders
What are teh treatments for anxiety and insomnia?
Benzodiazepines SSRIs BUSPIRONE Antihistamines 1st gen H1 blocker Alcohol, cannabis, opiatees Barbiturates
Where is GABA localized?
Substantia Nigra, globus pallidus, hippocampus, limbic structures, hypothalamus, spinal cord
What does bendoiazepines do?
enhance the effects of GABA on Cl- channels
What are the agonists of benzodiazepine receptor?
Diazepam, clinically useful
What is the antagonisnt of benzodiazepine?
Flumazenil
Why do we use benzodiazepines as opposed to barbituates?
benzodiazepines are much safer
How lipid soluble is diazepam?
very fast onset, because high lipid solubility and has rapideredistribution
HOw lipid soluble is lorazepam?
less lipophilic than diazepam. Absorption and onset of action are slower
What are the CNS effects of benzodiazepines?
decreased anxiety, sedation, hypnosis, muscle relaxation, anterograde amnesia, anticonvulsant action, minimal cv and respiratory actions
What benzo is used for alcohol withdrawal?
chlordiazepoxide
What benzo is used to treat actue manic episodes?
clonazepam
What benzo is used as a muscle relaxant?
diazepam
what is the only benzo used for both sleep and anxiety?
lorazapam
What are the adverse effects of benzos?
daytime sedation, ataxia, rebound insomnia, tolerancee and dependence, occasional idiosyncratic excitement and stimulation, increased death rate associated with use
Zolpidem is waht?
anti-insomnia, binds to BDZ receptor on GABA receptor, non-benzo chemically
preserves REM and non REM sleep
What is the mechanism of action of Barbiturates?
Act at GABA Cl ion channel complex; enhance action of GABA and increase inhibition
Baclofen is a muscle relaxant that acts through what mechanism?
alpha GABA receptor agonist
What are the four general componenets of general anesthetic state?
amnesia
unconsciousness (not always necessary)
analgesia (inability to interpret, repond to and remember pain(
Noxious painful stimuli don’t evoke movment or ANS
What is the dose of a gas directly related to?
It’s concentration at the alveolus
What is MAC?
minimal alveolar concentration that prevents movemnt in 50% of patients
How is potency for IV anesthetics determined?
free plasma concentration that produces loss of response to surgical incision in 50% of pts
What is the GABAa receptor?
GABA-regulated chloride channel; most anesthetics increase GABAa opening, results in hyperpolarization
Inhibition of NMDA receptors is used in what drug group?
some general anesthetics; results in hyperpolarization and reduced sodium and calcium influx
What are the stages of general anesthesia?
premedicaiton
induction
-usually by IV only by gas in emergent situations
Maintenaince
-gaseous usually have short half life and needed to be admin continuously
What is the mechanism of Sodium thiopental?
activate GABAa receptors
What is the role and class of sodium thiopental?
used to induce anesthesia; occurs 10-30 seconds after IV injection; barbiturates
Why are intra-arterial injections contraindicated in barbituate use?
results in inflammation and necrosis
What are the side effects of barbituates?
CNS depression, CV, respiratory depression
What is the most commonly used barbituate for anesthesia?
sodium thiopental
What is the most commonly used parenteral general anesthetic in US?
propofol
What is the mechanism of action of propofol?
GABAa mechanism
What is propofol used for during anesthesia?
both to induce and maintain anesthesia
What is the advantages of propofol?
antiemetic, quick onset of action, half life in body is 3.5 hours resulting in much less of a hangover
What are the unique side effects of propofol?
pain on injection, and often given with lidocaine, excitation on inducion
Why is propofol dangerous to administer?
more severe BP reduction than with thiopental
vasodilation and depression of myocardial cotnractility
blunts baroreflexes
respiratory more depression than thiopental
What drug is used in patients at risk for hypotension?
Etmoidate
What are the unique side effects of Etomidate?
high incidence of pain on injection and myoclonus
problems with nausea and vomiting
suppression of hte adrenocortical response; can result in higher mortality
What are the side effects of Etomidate non-unique?
CNS is the same as thiopental
CV is far less than thiopental
Respiratory less than thiopental
What type of anesthetic is ketamine?
dissociative anesthestic
- profound analgesia
- eyes open but unresponsive to commands
- amnesia
- bronchodilator no respiratory suppresion
What is the mechanism of action of ketamine?
NMDA receptor antagonist
What are the side effects of ketamine?
increased ICP Emergence delirium nystagmus, salivation, lacrimation, increase muscle tone spontaneous movment hypertension
What indicates ketamine use for patients?
children undergoing short, painful procedures
reserved for pateients iwth bronchospasms–bronchodilator
What are the properties of midazolam?
short acting benzo, GABAa activator
used alone for conscoius sedation or as an induction adgent
adjunct during local anesthesia
pre-op med for anxiety
What are the side effects of midazolam?
respiratory depression and arrest
caution in pts with parkinsons, bipolar and neuromusc disease
CV effects similar to thiopental
What is does blood:gas Ppartion coefficient indicate
if low need more inspired air, quick induction, recovery quick
high means less in inspired air, both induction and recovery are slow
What are important when induction occurs with gaseous anesthetic?
pulmonary ventilation (more important for gases with moderate to high blood gas PC)
anesthetic conc in inspired air
pulmonary blood flow
arteriovenous concentration gradient
What are the clinical uses of isoflurane?
most commonly used inhalational anesthetic in US and worldwide
What are the side effects of isoflurane?
airway irritant, coughing, decrease tidal volume, increase respiratory rate
anesthetic depress respiration
myocardial depression, arrythmias and ICP increase
What is the pharmacokinetics of desflurane?
very volatile at room temperatures, very low solubility in blood, rapid inductiona dn recovery
excreted unchanged in expired air
What are hte clinical uses of desflurane?
outpatient surgeries/maintenaince
not used to induce bc of resp irrtation
skeletal muscle relaxation
What are the side effects of desflurane
similar to isoflurane but a worse respiratory irritant
What are hte pharmokinetics of sevoflurane?
very low blood:gas PC
about 5% metabolized to fluoride ion
nephrotoxic effects
What is the clinical use of sevoflurane?
very popular for inpatient and outpatient to induce and maintain; not a respiratory irritant
What are the clinical use of Nitrous oxide?
weak anesthetic, cannot get enough into air to prodduce MAC
Good for sedation and alagesia, used together to reduce dose of other anaesthetics
What are the side effects of nitrous oxide?
contraindicated in pneumothorax
negative ionotrope but also sympathomimetic
respiratory effects are minimal
abuse liability
What are the mechanisms of local anesthetics?
bind reversibly to a site within the pore of voltage gated Na+ channels; blocking sodium entry when channel is openned
Bc of the role of these channels in AP initiation and generation
cause sensory loss and motor paralysis
In what order to local anesthetics have for sodium channesl?
lowest to highest affinity?
unactivated->activated->inactive
resting nerves less sensitive to block
nerves with positive membrane potential more sensitive to block
What are the sensitivity of neuron types to local anesthetics?
autonomic fibers, small non-myelinated C fibers, and small Adelta fibers, are blocked before larger myelinated Adelta, Abeta and Aalpha fibers
What is the order to the block of local anesthetics?
in order pain, cold, warmth, touch, deep pressure, motor and recover in reverse
What are the toxicity and side effects of local anesthetics?
interfere with function of all organs or transmission of impulses (CNS, ganglia, NMJ, Muscle)
systemic toxic reactions
intraneuronal injection can produce irreversible damage
S-enantiomer is less toxic than R-enantiomer in local anesthetics
What is the CNS toxicity of local anesthetics?
stim is seen first, depressiona t higher doses, death associated with sever toxicity usually caused by respiratory depression
What is the CV toxicity of local anesthetics?
general depression of CV system, down myocardial contractility
develop hypotension and arrythmias
How are local anesthetics metabolized?
ester local anesthetics inactivated by plasma esterases
amide local anesthetics metabolized in liver
What is the role of cocaine clinically?
local anesthetic, but also blocks uptake of norepi, potent vasoconstrictor, used for topical anesthesia of upper resp tract
What is tetracaine?
long acting ester local anesthetic
more potent and longer duration of action than procaine
used in spinal anesthesia and in topical and opthalmic preparations
What is benzocaine?
anesthetic with low water solubility, therefore too slowly abosrbed when applied topically
applied to wounds and ulcerated surfaces for pain relief
What is lidocaine?
intermediated duration of action, produce faster more intesnse and long lasting compared to prococaine
wide range of clinical uses
What is role of Bupivicaine?
long acting amide local anesthetic
capable of producing prologned anesthesia
provide more sensory than motor block
more cardiotoxic than equi-effective dose of lidocaine
What is ropivacaine?
long acting amide, anesthetic actions similar to bupivicaine with less toxicity
used for epidural and regional anesthesia
even more motor-sparing
Difference between amide and ester local anesthetics?
amides metabolized by liver with no allergic reaction
esters metabolizedd by plasma cholinesterases with rare allergic reactiosn
