General and Local Anesthetics Flashcards
What receptor does nitrous oxide (N2O) affect to induce anesthesia? Is it an agonist or antagonist?
NMDA-receptor antagonist
What class of drugs do isoflurane, desflurane, and sevoflurane belong to? What gas are they often combined with to cause the “2nd gas effect”?
Volatile anesthetics; often combined with N2O
Which volatile anesthetic is the gold standard for maintenance of anesthesia?
Isoflurane
List the 3 volatile anesthetics in order from most pungent to least pungent, most potent to least potent, and most soluble to least soluble.
Pungency: desflurane, isoflurane, sevoflurane
Potency: isoflurane, sevoflurane, desflurane
Solubility: isoflurane, sevoflurane, desflurane
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?
Sevoflurane; N2O is also used for children
What is the only anesthetic barbiturate available in the U.S., and what is it used for?
Methohexital; to induce general anesthesia, hypnosis, and sedation (not analgesic)
(note that the barbiturate thiopental is not allowed in the U.S.)
What receptor does methohexital act on to induce general anesthesia?
GABA-A receptor (agonist)
What class of drugs do methohexital, propofol, and etomidate belong to?
Intravenous anesthetics
What class of drugs do ketamine and dexmedetomidine belong to?
Intravenous anesthetics
What 4 receptor types does the IV anesthetic propofol act on, and how does it affect those receptors?
GABA-A receptor agonist, glycine receptor agonist, NMDA-glu receptor antagonist, α2 adrenergic receptor agonist
Which anesthetic is frequently used to sedate ICU patients?
Propofol
What receptor does the D-isomer of etomidate act on, and what is it used for?
GABA-A receptor (agonist); for hypnosis only (no analgesia)
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?
Propofol
What 2 receptors does ketamine act on, and what effect does it uniquely produce?
NMDA-glutamate receptor (antagonist) and kappa opiate receptor (agonist); produces a dissociative anesthesia (as well as unconsciousness, analgesia, and amnesia)
What anesthetic drug is associated with emergence delirium, and what other drugs are given to treat the delirium?
Ketamine; benzodiazepines to treat
What intravenous anesthetic can also be given intramuscularly to sedate pediatric and developmentally delayed adult patients?
Ketamine
Name 2 populations of patients that should not be given ketamine.
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)
What receptor does dexmedetomidine act on, and what is its FDA-approved use?
α2 adrenergic receptor; for sedation of <24 hours in ventilated ICU patients
What anesthetic is commonly used for awake intubations, awake craniotomies, procedural sedation, and facilitation of more “natural” sleep?
Dexmedetomidine
Name the only depolarizing muscle relaxant currently in use. Which receptors does it affect?
Succinycholine; affects all ACh receptors (NMJ, muscarinic, and nicotinic)
What class of drugs do pancuronium, vecuronium, and rocuronium belong to?
Non-depolarizing NMB agents (amino steroids)
What class of drugs do atracurium and cis-atracurium belong to?
Non-depolarizing NMB agents (isoquinolines)
What non-depolarizing NMB agent is the longest acting, with a duration of action of 60-90 minutes?
Pancuronium
Pancuronium is contraindicated in patients with what kinds of problems?
Renal insufficiency (excretion via the kidneys) or heart problems (increased HR)
What is the function of sugammadex?
It selectively reverses rocuronium by trapping the drug in its hydrophobic interior
What kind of side effects are caused by atracurium and cis-atracurium?
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
How are edrophonium, neostigmine, and pyridostigmine used in the anesthesia setting and what is their molecular mechanism of action?
Reverse a neuromuscular blockade by inhibiting AChE
Which 2 NMB reversal drugs are anti-muscarinic?
Glycopyrrolate and atropine
Of all the NMB reversal drugs, which one is the most commonly used?
Neostigmine
Which NMB has the most rapid onset and shortest duration of action?
Succinylcholine (60 sec onset and 9-12 min duration)
Which 4 anesthetic drugs can cause malignant hyperthermia?
All 3 of the volatiles (isoflurane, desflurane, and sevoflurane) and succinylcholine
What are the 2 classes of local anesthetics? What 2 local side effects can they produce?
Amides and esters; can cause transient neurological symptoms (severe pain) or neuronal injury.
Which (nonactive) form of a local anesthetic can cross the axonal membrane? How does the other (active) form work inside the neuron?
Nonionized (inactive) form cross the membrane; ionized (active) form blocks the intracellular portion of inactive/refractory voltage-gated sodium channels
Which 2 local anesthetics are associated with side effects of methemoglobinemia?
Benzocaine and prilocaine
Which class of local anesthetics are more likely to cause allergic reactions because they contain PABA derivatives?
Esters
What kind of anesthetics are cocaine, procaine, and benzocaine? How are they metabolized?
Ester anesthetics; metabolized by plasma esterases
What kind of anesthetics are lidocaine, mepivicaine, bupivicaine, etidocaine, prilocaine, ropivicaine, dibucaine (and what about the name gives it away)?
Amide anesthetics (have two or more “i”s in the name)
How are amide anesthetics metabolized and cleared?
Metabolized by liver enzymes and cleared by the kidney
Local anesthetics commonly cause side effects in which two systems of the body?
In the CNS and cardiovascular systems (including vasodilation and bradycardia)
