General and Local Anesthetics

Question 1

What receptor does nitrous oxide (N2O) affect to induce anesthesia? Is it an agonist or antagonist?

Answer 1

NMDA-receptor antagonist

Question 2

What class of drugs do isoflurane, desflurane, and sevoflurane belong to? What gas are they often combined with to cause the “2nd gas effect”?

Answer 2

Volatile anesthetics; often combined with N2O

Question 3

Which volatile anesthetic is the gold standard for maintenance of anesthesia?

Answer 3

Isoflurane

Question 4

List the 3 volatile anesthetics in order from most pungent to least pungent, most potent to least potent, and most soluble to least soluble.

Answer 4

Pungency: desflurane, isoflurane, sevoflurane
Potency: isoflurane, sevoflurane, desflurane
Solubility: isoflurane, sevoflurane, desflurane

Question 5

Which volatile anesthetic is used most often for mask induction in children and adults? What second gas can also be used for mask induction in children?

Answer 5

Sevoflurane; N2O is also used for children

Question 6

What is the only anesthetic barbiturate available in the U.S., and what is it used for?

Answer 6

Methohexital; to induce general anesthesia, hypnosis, and sedation (not analgesic)
(note that the barbiturate thiopental is not allowed in the U.S.)

Question 7

What receptor does methohexital act on to induce general anesthesia?

Answer 7

GABA-A receptor (agonist)

Question 8

What class of drugs do methohexital, propofol, and etomidate belong to?

Answer 8

Intravenous anesthetics

Question 9

What class of drugs do ketamine and dexmedetomidine belong to?

Answer 9

Intravenous anesthetics

Question 10

What 4 receptor types does the IV anesthetic propofol act on, and how does it affect those receptors?

Answer 10

GABA-A receptor agonist, glycine receptor agonist, NMDA-glu receptor antagonist, α2 adrenergic receptor agonist

Question 11

Which anesthetic is frequently used to sedate ICU patients?

Answer 11

Propofol

Question 12

What receptor does the D-isomer of etomidate act on, and what is it used for?

Answer 12

GABA-A receptor (agonist); for hypnosis only (no analgesia)

Question 13

A perfusion syndrome, most likely caused by fatty acid oxidation, that causes metabolic acidosis, rhabdomyolysis, renal failure, lowering of BP, bradycardia, and death, is associated with several days administration of what drug?

Answer 13

Propofol

Question 14

What 2 receptors does ketamine act on, and what effect does it uniquely produce?

Answer 14

NMDA-glutamate receptor (antagonist) and kappa opiate receptor (agonist); produces a dissociative anesthesia (as well as unconsciousness, analgesia, and amnesia)

Question 15

What anesthetic drug is associated with emergence delirium, and what other drugs are given to treat the delirium?

Answer 15

Ketamine; benzodiazepines to treat

Question 16

What intravenous anesthetic can also be given intramuscularly to sedate pediatric and developmentally delayed adult patients?

Answer 16

Ketamine

Question 17

Name 2 populations of patients that should not be given ketamine.

Answer 17

Patients with coronary artery disease (bc of increased HR and oxygen consumption) and patients with intracranial mass lesions (bc of increased cerebral blood flow and intracranial pressure)

Question 18

What receptor does dexmedetomidine act on, and what is its FDA-approved use?

Answer 18

α2 adrenergic receptor; for sedation of <24 hours in ventilated ICU patients

Question 19

What anesthetic is commonly used for awake intubations, awake craniotomies, procedural sedation, and facilitation of more “natural” sleep?

Answer 19

Dexmedetomidine

Question 20

Name the only depolarizing muscle relaxant currently in use. Which receptors does it affect?

Answer 20

Succinycholine; affects all ACh receptors (NMJ, muscarinic, and nicotinic)

Question 21

What class of drugs do pancuronium, vecuronium, and rocuronium belong to?

Answer 21

Non-depolarizing NMB agents (amino steroids)

Question 22

What class of drugs do atracurium and cis-atracurium belong to?

Answer 22

Non-depolarizing NMB agents (isoquinolines)

Question 23

What non-depolarizing NMB agent is the longest acting, with a duration of action of 60-90 minutes?

Answer 23

Pancuronium

Question 24

Pancuronium is contraindicated in patients with what kinds of problems?

Answer 24

Renal insufficiency (excretion via the kidneys) or heart problems (increased HR)

Question 25

What is the function of sugammadex?

Answer 25

It selectively reverses rocuronium by trapping the drug in its hydrophobic interior

Question 26

What kind of side effects are caused by atracurium and cis-atracurium?

Answer 26

Atracurium can cause histamine release if given as a rapid IV bolus, leading to transiently increased HR and decreased BP; cisatracurium has no side effects

Question 27

How are edrophonium, neostigmine, and pyridostigmine used in the anesthesia setting and what is their molecular mechanism of action?

Answer 27

Reverse a neuromuscular blockade by inhibiting AChE

Question 28

Which 2 NMB reversal drugs are anti-muscarinic?

Answer 28

Glycopyrrolate and atropine

Question 29

Of all the NMB reversal drugs, which one is the most commonly used?

Answer 29

Neostigmine

Question 30

Which NMB has the most rapid onset and shortest duration of action?

Answer 30

Succinylcholine (60 sec onset and 9-12 min duration)

Question 31

Which 4 anesthetic drugs can cause malignant hyperthermia?

Answer 31

All 3 of the volatiles (isoflurane, desflurane, and sevoflurane) and succinylcholine

Question 32

What are the 2 classes of local anesthetics? What 2 local side effects can they produce?

Answer 32

Amides and esters; can cause transient neurological symptoms (severe pain) or neuronal injury.

Question 33

Which (nonactive) form of a local anesthetic can cross the axonal membrane? How does the other (active) form work inside the neuron?

Answer 33

Nonionized (inactive) form cross the membrane; ionized (active) form blocks the intracellular portion of inactive/refractory voltage-gated sodium channels

Question 34

Which 2 local anesthetics are associated with side effects of methemoglobinemia?

Answer 34

Benzocaine and prilocaine

Question 35

Which class of local anesthetics are more likely to cause allergic reactions because they contain PABA derivatives?

Answer 35

Esters

Question 36

What kind of anesthetics are cocaine, procaine, and benzocaine? How are they metabolized?

Answer 36

Ester anesthetics; metabolized by plasma esterases

Question 37

What kind of anesthetics are lidocaine, mepivicaine, bupivicaine, etidocaine, prilocaine, ropivicaine, dibucaine (and what about the name gives it away)?

Answer 37

Amide anesthetics (have two or more "i"s in the name)

Question 38

How are amide anesthetics metabolized and cleared?

Answer 38

Metabolized by liver enzymes and cleared by the kidney

Question 39

Local anesthetics commonly cause side effects in which two systems of the body?

Answer 39

In the CNS and cardiovascular systems (including vasodilation and bradycardia)