Drugs In Anesthesiology Flashcards
Drugs that end in -flurane are ____
inhalation anesthetics
What are three anesthetic adjuncts?
Benzos
Analgesics (Opioids/NSAID’s)
Alpha 2 agonist
Drugs that end in -caine belong to what drug class?
Local anesthetics
Drugs that end with -curium or curonim belong to what class?
NM Blocking Agents
Dexmedetomidine belongs to what drug class?
alpha 2 adrenergic agonists
What type of sedaation produces alleviation of anxiety and pain. However, in this state, patient retains ability to maintain patent airway and is responsive to verbal commands?
Conscious Sedation
What are the five primary effects of general anesthesia?
1) Unconsciousness
2) Amnesia
3) Analgesia
4) Inhibition of autonomic reflexes
5) Skeletal muscle relaxation
True or False: Hippocampus and Amygdala are important for amnesia
True
True or False: Thalamus and brain stem are important for ANS control
True
Guedel’s Stages of Anesthesia?
stage 1: analgesia - pain free, without amnesia
stage 2: excitement - delirium, may vocalize. There is amnesia. RR, HR, and BP are rapid and increase.
stage 3: surgical anesthesia - slow of HR and RR; cessation of spontaneous breathing
stage 4: medullary depression - severe CNS depression (vasomotor center in medulla and respiratory center in brainstem)
At what Guedel stage do most surgical operations occur in?
Stage 3
True or False: Eyes become more dilated in stage 3 (surgical anesthesia)
True
Hemodynamic effects of general anesthesia?
- decrease arterial BP
- blunt baroreceptor control
- decrease sympathetic tone
True or False: General anesthesia can reduce/eliminate ventilatory drive - endotrach intubation helps with this
True
Consequences of general anesthesia causing hypothermia?
Reduced metabolic rate and altered themoregulation
General anesthesia targets ___ and ___, which can lead to vomiting and nausea
chemoreceptor trigger zone and brainstem vomiting center
____: refers to use of multiple classes of drugs to achieve desired depth of anesthesia
Balanced anesthesia
What is the principal molecular target of anesthetic action?
Neuronal ion channels
(mediates impulse conduction in the CNS)
Which two channels are the primary INHIBITORY ion channels considered to be legitimate candidates of anesthetic action?
1) Chloride channels - GABA/Glycine-R
2) Potassium channels
Excitatory ion channel targets include those activated by:
- Ach (nicotinic/muscarinic receptors)
- Glutamate (AMPA)
- Serotonin
What is the key factor governing the pharmacokinetics of parentral anesthetics?
Hydrophobicity
True or False: Anesthetic potency is closely correlated to lipid solubility
True
What general anesthetics have interaction sites at GABA-a receptor?
Etomidate
Propofol
Diazepam
- GABA binds at b-a subunit interface in extracellular domain
Ketamine binds to ____ site of NMDA-R while Glycine binds to ___ site and NMDA binds to ___ site
Ketamine - PCP Site
Glycine - Glycine Site
NMDA - Glutamate Site
Which receptors requires binding of both glycine and glutamate?
NMDA Receptor
___ is redistributed after IV bolus administration. How are the kinetics described?
Thiopental
- Kinetics: Three compartment model (blood/brain/skeletal muscle)
True or False: Thiopental is terminated by redistribution for a single IV dose
True
Do Thiopental and Diazepam have a short or long infusion duration?
Longer
_____ of a drug describes the elimination half-time after discontinuation of a continuous infusion as a function of duration of infusion
Context sensitive half time
After prolonged infusions, duration of action are dependent on interaction between….
1) rate of drug distribution
2) amount of drug accumulated in fat
3) drug’s metabolic rate
What are the three parenteral anesthetics?
1) Propofol
2) Etodimate
3) Ketamine
_____ potentiates GABA receptor and blocks Na channel and is used for INDUCING anesthesia
Propofol
What do all the parenteral anesthetics have in common?
-Rapid onset
-Short duration
-Often used in procedures for rapid return to pre-op mental status
How does the propofol dosage vary in kids vs. elderly?
Lower dose in elderly, higher in kids (rapid clearance)
_____: Rare complication associated with prolonged and high dose propofol infusion in young or head injured patients
note: associated with increased intercranial pressure
Propofol Infusion Syndrome
True or False: Ketamine stimulates GABA receptors
False - Etodimate and Methohexital stimulate GABA receptors
Which parenteral anesthetics is preferred for people with risk of hypotension or MI?
Etodimate
Which parenteral anesthetic can elevate EEG activity and is associated with SEIZURE activity?
Etodimate
If there is an asthmatic, pediatric patient at risk of hypotension, what is the best parenteral anesthetic choice for them?
Ketamine
A patient is experiencing hallucinations after receiving a parenteral anesthetic. After taking vitals, it is revealed that patient has elevated HR, BP, CO, CBF, and ICP. What parenteral was likely used?
Ketamine
True or False: Emergence delirium is seen in patients after taking Ketamine
True
Thiopental and Methohexital belong to what drug class?
Barbituates
____ is an NMDA antagonist/parenteral anesthetic while ____, a barbituate, stimulates GABA receptors
Ketamine = NMDA antagonist
Methohexital = GABA
True or False: Both Methohexital (barbituate) and Propofol (parentral) can be used for anesthetic induction
True
Why is methohexital safer for epileptic patients?
Respiratory and EEG depressant
Effect of intra-arterial injection of thiobarbituates?
Severe inflammation and possible necrosis
NO is a ___ inhalation anesthetic
gaseous
Features of volatile anesthetics?
-Low vapor pressures
-High BP
-Lipids at room temperature
Induction of anesthesia is SLOWER under what condition?
More soluble anesthetic gases
Which is more soluble (and therefore causes slower induction of anesthesia?): halothane or NO?
Halothane
True or False: NO typically has to be used with another drug
True
Induction of anesthesia is much ___ with halothane, compared to NO
slower
What three anesthetics have LOW blood solubility? HIGH blood solubility?
Low =NO, Desflurane, Sevoflurane
High = Halothane and Isoflurane
For anesthetics with ___ blood solubility, equilibrium is quickly established and the blood concentration rises rapidly
LOW
For ___ and ___, which are anesthetics that have greater solubility, more molecules dissolve in blood before partial pressure changes significantly and arterial concentration of gas increases less rapidly
Halothane and Isoflurane
How can an anesthesiologist accelerate induction?
Increase the inspired anesthetic partial pressure to create steeper gradient between 1) inspired and 2) alveolar partial pressure
How can the doctor deliver LARGER amounts of anesthetic agent FASTER?
Increase tidal volume and RR
A fourfold increase in ventilation rate nearly doubles the FA/FI ratio for ___ during first 10 minutes, but there is only a 15% increase in ratio for ___
halothane ; NO
___: the concentration of inhaled anesthetic needed to eliminate movement in 50% of patients (ED50)
Minimum Alveolar Concentration (MAC)
The inverse of MAC is an index of the ____ of anesthetic
potency
Numerically, MAC is __ for potent anesthetics and ___ for less potent anesthetics
small mac = potent (halothane)
large mac = less potent (NO)
True or False: NO alone cannot produce anesthesia
True
Are less soluble anesthetics (such as NO or Desflurane) eliminated faster or more slowly compared to soluble ones?
Faster
Insoluble anesthetics that prefer the __ phase over blood and will rapidly diffuse into alveolus and be removed from body via: lung ventilation
What is one of the most important factors governing the rate of recovery?
gas
- Blood: gas partition coefficient
Since the concentration of anesthetic in the inspired as cannot be reduced below zero, ___ is the only way to speed recovery
hyperventilation
Note: metabolism does NOT play a significant role
Four types of ACUTE toxicity that result from anesthetic agents?
1) Nephrotox
2) Hematotox
3) Malignant Hyperthermia (genetic disorder of skeletal muscle that occurs in certain people exposed to VOLATILE anesthetics_
4) Hepatotox (halothane hepatitis) - most potent volatile anesthetic
Isoflurane, Enflurane, Sevoflurane, and Desflurane belong to what drug class?
Inhalation Anesthetics
What is the most commonly used inhalation anesthetic? What does it do?
Isoflurane
- maintains anesthesia
True or False: Isoflurane is a positive modulator of GABA-A
False - Enflurane is !
Which inhalation anesthetic increases GABA release and glutamate re-uptake potentiate glycine receptor activity (decreases motor function)?
Isoflurane
Which inhalation anesthetic decreases baroreceptor function?
Isoflurane
Which inhalation anesthetic can increase intracranial pressure and cause seizures?
Enflurane
Clinical application of both Isoflurane and Enflurane?
Maintain anesthesia
True or False: Both Sevoflurane and Desflurane can be used for outpatient surgeries (rapid onset, rapid recovery)
True
Which inhalation anesthetic would you select for a patient with myocardial ischemia?
Sevoflurane
___, an inhalation anesthetic, is an airway irritant
Desflurane
___ is a weak inhalation anesthetic agent used for weak analgesic effects (dental) - it is also used as ADJUNCT to other anesthetics
NO
What patient populations should not have NO?
- Ear or bowel obstructions
- Intraocular and intracranial air bubbles
When discontinuing ____, administer 100% oxygen to avoid diffusional hypoxia. This drug can also increase CBF and ICP.
NO
A nondepolarizing blocker prevents the opening of the _____ channel upon binding by blocking __ from binding
A depolarizing blocker will both ___ the receptor and block the ____ channel
sodium; Ach
note: If ach can’t bind, channel does not open
occupy; sodium channel
What type of NM Blocking agent is Succinylcholine? Clinical use?
Depolarizing blocker
- Clinical use: Place endotracheal tube
True or False: Surgical relaxation is just one use of NM Blocking Drugs
True
(particularly for: intra-abdominal and intra-thoracic procedures)
- Blocks skeletal muscle activation
Uses of NM Blocking Agents?
1) Surgical Relaxation
2) Endotracheal Intubation
3) Control of ventilation
4) Treating convulsions
- Used to attenuate peripheral (motor) manifestations of convulsions
True or False: NM Blocking Agents cross BBB
False - they do NOT
______ is a depolarizing NM blocker that allows for persistent depolarization at the NMJ. It is commonly used to place endotracheal tube.
Succinylcholine
Succinylcholine is rapidly metabolized by ___
cholinesterase
Toxicities associated with succinylcholine?
Arrythmia
Hyperkal
Increased intraocular pressure
Increased intraabdominal pressure
Post-op pain
What drug class do atracurim, vecuronium, rocuronium, pipercuronium, etc. belong to?
Non-depolarizing NM Blocking Agents
(competitive antagonists at nAch-R, esp NM Junction)
Clinical use of Non-depolarizing NM Blocking Agents?
Prolonged relaxation for surgical procedures
How do you reverse the actions of Rocuronium and Vecuronium?
Sugammadex
True or False: An AchE Inhibitor (neostigmine) + muscarinic receptor antagonist can be used to reverse actions of non-depolarizing NM Blocking Agent
True
Sugammadex encapsulates and prevents ___ molecules from binding to ___ receptors
Encapsulated ___ is inactivated and cleared
NMBA; Ach
Sugammadex encapsulates ___ or _____ in plasma at 1:1
rocuronuium or vercuronium
True or False: Sugammadex is a competitive inhibitor of rocuronuium and vercuronium
False - non-competitive
Role of Sugammadex?
Reversal of NM Blockade
Bradycardia, hypersensitivity, and recurrence of NM blockade are side effects of which NMBA inhibitor?
Sugammadex
What three benzodiazepines are used as anesthetic adjuncts?
1) Midazolam
2) Diazepam
3) Lorazepam
How do benzodiazepines work?
Enhance GABA
Most commonly used anesthetic adjunct/benzo
Midazolam
Uses of benzos, an anesthetic adjuncts?
1) Amnesia
2) Anxiety
3) Pre-anesthesia sedation
4) Sedation in procedures where general anesthesia is not needed
_____ is an alpha-2 adrenergic agonist that is used as an anesthetic adjunct
Dexmedetomidine
Uses of dexmedetomidine (alpha-2 adrenergic agonist)?
1) Short term sedation in critically ill adults
2) Sedation prior to surgery
Why can dexmedetomidine cause hypotension and bradycardia?
Decreased catecholamine release in CNS
True or False: Both opioids and NSAID’s are analgesics
True
What are three opioids commonly used in surgery?
1) Fentanyl
2) Merperidine
3) Morphine
- All bind to opioid receptor agonist
Clinical application of opioids in surgery?
- Reduce anesthetic requirement
- Minimize hemodynamic changes to painful stimuli
____ are the primary analgesic during peri-operative period
Opioids
Opioids are often administered ___ and ___ for managing acute and chronic pain
intrathecally ; epidurally
___ is a cox inhibitor that is used for minor surgical procedures to control post-op pain
Acetaminophen
Role of oxygen as a therapeutic gas?
-Reverse or prevent hypoxia
How can excessive O2 affect ventilation, HR, and CO?
Decrease it
True or False: If you are administering O2 for more than 1 hr to a patient, it should be humidified
True
Clinical uses of CO2?
1) Insufflation during endoscopic procedures
2) Flooding surgical field during cardiac surgery
3) Adjusting pH during cardiopulm bypass
Net effect of CO2 on CO, HR, and BP?
Increase all
What are the three structural regions that make up local anesthetics?
1) Hydrophobic/Aromatic ring
2) Linker Region - less sensitive to breakdown
3) Substituted Amine - hydrophillic (keep in solution)
Local anesthetics bind inside of the ____ channel and block ___ entrance. This prevents neuronal depolarization and AP formation, thus blocking pain signal transmission
ion channels; sodium
True or False: Local anesthetics work by causing neuronal depolarization and action potential formation, thereby BLOCKING transmission of pain signals
False - Local anesthetics work by PREVENTING neuronal depolarization and action potential formation, thereby BLOCKING transmission of pain signals
True or False: The un-protonated form of LA crosses into intracellular membrane via lipid membrane, become protonated, then blocks receptor intracellularly
True
Where are local anesthetics most likely to be absorbed?
Intercostal region
Anesthetics that are more lipid soluble are generally more ___, have ____ duration of action, and take ___ to achieve clinical effect
potent; longer ; longer
When used for major conduction blocks, local anesthetics will mostly be absorbed ____, and will not be absorbed much in ____/____ region
intercostal (highest serum level); femoral/sciatic
Local Anesthetic blockage is ___ and ___ dependent
voltage; time
How does the repetitive activity, as seen in local anesthetic, affect sodium channel block?
Pulses rapidly decrease, leading to a block
When local anesthetics are injected extradurally, it is referred to as a ___ block
epidural block
A ____ is a specific type of epidural block in which a needle is inserted into caudal canal via sacral hiatus
Caudal Block
Injections around peripheral nerves is known as ___ blocks
perineural blocks
Injection into CSF in the subarachnoid space is referred to as ____ block
spinal block
What two systemic effects that are associated with local anesthetics?
1) CNS Toxicity - sedation, light-headed, disturbances, restless
2) Cardiotoxicity (effect on NE/Epi)
What types of neurotoxicity can result from use of LA?
1) Neural Injury
2) Transient neurological symptoms
Transient pain/dysesthesia has been linked to use of ___ for spinal anesthesia
lidocaine
Lidocaines, Prilocaines, etc. (-caines) block ___ channels
sodium
The alveolar anesthetic concentration (Fa) approaches the inspired anesthetic concentration (FI) fastest for the ____ soluble agents
LEAST
How does Isoflurane affect ventilation, RBF?
CBF, BP, and coronary blood flow?
Isoflurane will:
- Decrease ventilation and RBF
- Increase CBF
- Can induce HYPOTENSION
- Increase coronary blood flow (and therefore, decrease myocardial O2 consumption)
note: it’s excreted by lungs unchanged
What is the preferred agent for anesthetic induction?
Sevoflurane
What three drug classes are adjuncts?
1) Benzos (lams/pams)
2) alpha 2 adrenergic agonists
3) Analgesics (opioids and NSAIDs)
What three drugs make up the SHORT-DURATION amides? How do they work?
1) Lidocaine
2) Prilocaine
3) Mepivacaine
Block Na channels
- can last longer w epi
Toxicity: CNS excitation w high volume blocks; local neurotoxicity
Which TWO short acting amides are associates with the risk of methemoglobinemia?
1) Prilocaine
2) Mepvicaine
What are the three longer-acting amide drugs?
Bupivacaine
Rapivacaine
Levobupvicaine
Not often used topically or intravenously (short acting ones, by contrast, are)
AE associated with long acting amides?
CNS excitation and cardiovascular collapse with high volume blocks
____ is a amide that is commonly used as a dental anesthetic
Articaine
True or False: Chloroprocaine has the same toxicities associated with lidocaine
True
True or False: Procaine is used epidurally
False
True or False: All the ester and amide drugs block Na channels
True
Which ester is primarily used for spinal anesthesia?
Tetracaine
True or False: Both Chloroprocaine and Procaine are use topically or intravenously
False - they are NOT
True or False: Benzocaine is exclusively used for topical anesthesia
True
