anesthetics - khan

which of the following are inhalation and IV anesthetics?

a. general anesthetics

b. local anesthetics

a.

what kind of inhalation anesthetic is nitrous oxide?

a. non-halogenated (gaseous)

b. halogenated (volatile)

a.

what kind of inhalation anesthetic is isoflurane, desflurane, and sevoflurane?

a. non-halogenated (gaseous)

b. halogenated (volatile)

b.

list the IV general anesthetics

propofol

dexmedetomidine

lorazepam

midazolam

ketamine

etomidate

what are the 5 desired effects of general anesthetics?

1. analgesia

2. amnesia

3. immobility

4. inhibition of autonomic reflexes

5. unconsciousness

list the 4 stages of general anesthesia

1. analgesia

2. excitement

3. surgical anesthesia

4. medullary depression

what stage of general anesthesia must be avoided?

a. stage I: analgesia

b. stage II: excitement

c. stage III: surgical anesthesia

d. stage IV: medullary depression

d.

the inhalation anesthestics are either ________ or ________ whose gaseous phase can be inhaled

gases or volatile liquids

how is the potency of inhalational anesthetics expressed?

in terms of the inspired concentration of the anesthetic required to produce anesthesia in half the subject

AKA the minimal alveolar concentration (MAC)

potency = _______

a. MAC/1

b. 2/MAC

c. MAC/3

d. 1/MAC

d.

based on this graphic, which agent is more potent?

a. halothane

b. isoflurane

c. desflurane

d. nitrous oxide

a.

remember potency = 1/MAC

describe the MOA of inhalational anesthetics

• potentiate inhibitory synaptic activity

  • enhance GABA and glycine receptors, incr. Cl- influx, activate K+ channels —> hyperpolarization

• diminish excitatory synaptic activity

  • inhibit nACh and NMDA receptors, decr. Ca and Na influx

what is the least potent inhalational anesthetic and is also known as “laughing gas”?

nitrous oxide

what inhalational anesthetic has very rapid induction (very low gamma (blood/gas)) with greater solubility in the gas —> faster induction?

nitrous oxide

what halogenated anesthetic is a volatile liquid at room temperature with PUNGENT odor, and is typically used for maintenance? (SATA)

a. desflurane

b. sevoflurane

c. isoflurane

a. c.

what halogenated anesthetic is widely used for outpatient surgery because it has rapid onset AND recovery?

a. desflurane

b. sevoflurane

c. isoflurane

a.

what inhalational anesthetic is metabolized by CYP2E1 to release fluoride, potentially causing nephrotoxicity?

a. desflurane

b. sevoflurane

c. isoflurane

b.

what is the drug of choice for pediatric anesthetic induction?

a. desflurane

b. sevoflurane

c. isoflurane

d. nitrous oxice

b.

T/F isoflurane has a relatively fast onset and delivery

FALSE — relatively slow

what IV general anesthetic potentiates the GABA_A receptor, is formulated as an emulsion (pain), and has potential for bacterial growth?

a. propofol (diprivan)

b. dexmedetomidine (precedex)

c. midazolam

d. lorazepam

a.

what are the effects of propofol (diprivan)? (SATA)

a. decr. BP

b. analgesia

c. respiratory depression

a. c.

list ADRs of propofol (diprivan)

hypotension

apnea

hypertriglyceridemia

green urine/hair/nail beds

propofol infusion syndrome (PRIS)

what IV general anesthetic is contraindicated with an allergy to egg or soy?

a. propofol (diprivan)

b. dexmedetomidine (precedex)

c. midazolam

d. lorazepam

a.

dexmedetomidine (Precedex) produces _________ and ________ by alpha_2A activation

sedation and analgesia

list ADRs of dexmedetomidine (precedex)

hypotension

hypertension (higher doses)

bradycardia

what benzodiazepines are used as IV general anesthetics?

MOA?

midazolam and lorazepam

MOA: bind to allosteric site on GABA —> intensifying the inhibitory effects of endogenous GABA by increasing the frequency of chloride channel opening

what is the difference between the MOA of baributurates and benzodiazepines?

both incr. the duration of channel openings

barbiturates also can directly mimic GABA at higher doses

what is the risk associated with using benzodiazepines plus an opioid?

sedation

respiratory depression

coma

death

what is the boxed warning for midazolam?

respiratory depression/arrest

-use lower end of dosing in debilitated and geriatric population

-do NOT admin by rapid IV in neonates

ketamine is a ________

NMDA receptor antagonist

T/F the S isomer of ketamine is used because it’s more potent

FALSE — racemic mixture is used, but S isomer is more potent

what can reduce the incidence of emergence reactions (vivid dreams, hallucinations, delirium) with ketamine?

benzodiazepines

list ADRs of ketamine

• emergence reactions

  • vivid dreams

  • hallucinations

  • delirium

• incr. HR

• incr. BP

• incr. CO

what drug causes hypnosis but no analgesic effect and is ultra short-acting?

etomidate

list ADRs of etomidate

n/v

inhibits cortisol production

-monitor hypotension, hyperkalemia

T/F local anesthetics abolish pain sensation in a limited area of the body WITHOUT producing unconsciousness

TRUE

what would you use for topical burns and small cuts, as an injection during dental procdure, or epidural blocks during obstetric procedures/surgery?

a. inhalation anesthetics

b. IV general anesthetics

c. local anesthetics

c.

T/F local anesthetics are specific for pain fibers

FALSE - NOT specific; can block other fibers and APs

how do local anesthetics work?

do you need a low concentration or high concentration for it to work?

prevent impulse transmission by blocking individual sodium channel sin neuronal membranes

high concentration

most local anesthetic agents consist of a __________ connected to an _________ by an aliphatic chain via ________

lipophilic group connected to an ionizable group (tertiary amine) via ester/amide

explain how local anesthetics work as uncharged vs cations

cation: most active at receptor

uncharged: rapid penetration of membranes

list the ester local anesthetics

• tetracaine

• procaine

• benzocaine

list the amide local anesthetics

• lidocaine

• mevipacaine

• bupivacaine

• levobupivacaine

• ropivacaine

• prilocaine

which has a shorter duration of action?

a. ester local anesthetics

b. amide local anesthetics

a.

idk if we need to know structures at all

which of these is procaine (hint: it’s an ester series)?

a.

idk if we need to know structures at all

which of these is lidocaine (hint: it’s an amide series)?

b.

what group is essential for local anesthetic activity because it is important for binding to the receptors?

a. aromatic ring or dimethyl phenyl group

b. di-ortho substitution

c. aliphatic chain

d. tertiary alkyl amine

a.

_______ provides enhanced protection from amide hydrolysis in amide local anesthetics, resulting in longer duration of action?

a. aromatic ring or dimethyl phenyl group

b. di-ortho substitution

c. aliphatic chain

d. tertiary alkyl amine

b.

local anesthetics

_______ connects lipophilic portion and hydrophilic portion and is usually 1-3 carbons in length

a. aromatic ring or dimethyl phenyl group

b. di-ortho substitution

c. aliphatic chain

d. tertiary alkyl amine

c.

________ are more resistant to metabolic inactivation

________ are more susceptible to ester hydrolysis

amide local anesthetics are more resistant to metabolic inactivation

ester local anesthetics are more susceptible to ester hydrolysis

most local anesthetics have a _________ that helps in enhancing water solubility and interacts with receptor binding site when protonated

a. aromatic ring or dimethyl phenyl group

b. di-ortho substitution

c. aliphatic chain

d. tertiary alkyl amine

d.

local anesthetics show better absorption in _________ areas following multiple administrations

a. poorly perfused areas

b. highly perfused areas

b.

what is seen in the epinephrine-local anesthetic combinations?

increases the conc. and duration of action of LA at the site of injection

reduces systemic absorption of LA

reduces potentials for systemic toxicity

what are the downsides of using vasoconstrictors (epinephrine) with local anesthetics?

do NOT use in extremities —> limited circulation

can lead to hypoxia and damage

sequestration of LAs occurs in _______

fatty tissue

ester type LAs are hydrolyzed very rapidly in the blood by ________

a. butyryl cholinesterase

b. cytochrome P450

a.

amide type LAs are hydrolyzed by liver microsomal __________ so toxicity is more likely to occur in pts with liver disease

a. butyryl cholinesterase

b. cytochrome P450

b.

what is the MOA of local anesthetics?

block voltage-gated sodium channels

prevent depolarization and AP

what is the choice of local anesthetic for a specific procedure based on?

how can we prolong the duration of action for a short/intermediate acting agent?

based on duration of action

prolong by increasing dose or administering with a vasoconstrictor

what CV toxicities can be caused by local anesthetics?

severe hypotension

block cardiac Ca channels

prilocaine in high doses causes ________ as a result from _______

how do we fix it?

causes methemoglobinemia (cyanotic and chocolate-colored blood) as a result from formation of a metabolite (oxidizing agent)

IV admin of reducing agents converts it back to Hb

ester type drugs are metabolized to ________ derivatives which are responsible for _______

PABA —> allergic reactions

what drug exists in unionized form under most physiological conditions because it lacks a tertiary amine and has a short duration of action?

benzocaine

what local anesthetic has ADRs of drowsiness and seizure?

lidocaine

what drug has a higher lipid solubility and decreased hepatic degradation than lidocaine?

which enantiomer is responsible for cardiotoxicity?

bupivacaine

R enantiomer —> ventricular arrhythmia

which has a lower cardiotoxicity:

a. bupivacaine

b. levobupivacaine

b.