Neuro: Pharm - Anesthetics

Question 1

Barbiturates:

Answer 1

Phenobarbital, pentobarbital, thiopental, secobarbital

Question 2

Barbiturates: MOA

Answer 2

Facilitate GABA A action by increasing duration of Cl- channel opening, thus decreasing neuron firing (barbidurates increases duration). Contraindicated in porphyria.

Question 3

Barbiturates: Uses

Answer 3

Sedative for anxiety, seizures, insomnia, induction of anesthesia (thiopental)

Question 4

Induction of anesthesia

Answer 4

thiopental

Question 5

Barbiturates: Toxicity

Answer 5

Respiratory and cardiovascular depression (can be fatal); CNS depression (can be exacerbated by EtOH use); dependence; drug interactions (induces cytochrome P-450)

Question 6

Overdose Tx of barbiturates:

Answer 6

supportive –> assist respiration and maintain BP

Question 7

Benzodiazepines:

Answer 7

Diazepam, lorazepam, triazolam, temazepam, oxazepam, midazolam, chlordiazepoxide, alprazolam

Question 8

Benzos: MOA

Answer 8

Facilitate GABA A action by increasing FREQUENCY of Cl- channel opening.
Most have long half lives and active metabolites
“Frenzodiazepines” increase frequency
Benzos, barbs, and EtOH all bind GABA A, which is a ligand-gated Cl- channel

Question 9

Short acting Benzos:

Answer 9

alprazolam, triazolam, oxazepam, midazolam

ATOM

Question 10

Benzos: uses

Answer 10

anxiety, spasticity, status epilepticus (lorazepam and diazepam), detoxification (especially alcohol withdrawal-DTs), night terrors, sleepwalking, general anesthetic (amnesia, muscle relaxation), hypnotic (insomnia)

Question 11

Benzos: toxicity

Answer 11

dependence, additive CNS depression effects with alcohol. Less risk of respiratory depression and coma than with barbiturates

Question 12

Tx benzo overdose with:

Answer 12

Flumazenil (competitive antagonist at GABA benzodiazepine receptor)

Question 13

Nonbenzodiazepine Hypnotics:

Answer 13

Zolpidem (Ambien), Zaleplon, esZopiclone.

“All ZZZs put you to sleep”

Question 14

Nonbenzo hypnotics: MOA

Answer 14

Act via BZ1 subtype of GABA receptor. Effects reversed by flumazenil

Question 15

Nonbenzo hypnotics: uses

Answer 15

Insomnia

Question 16

Nonbenzo hypnotics: toxicity

Answer 16

Ataxia, HA, confusion.
Short duration bc of rapid metabolism by liver enzymes. Unlike older sedative-hypnotics, cause only modest day-after psychomotor depression and few amnestic effects. Decrease dependence risk than benzodiazepines.

Question 17

Inhaled anesthetics:

Answer 17

Halothane, enflurane, isoflurane, sevolfurane, methoxyflurane, nitrous oxide, desflurane

Question 18

Inhaled anesthetics: MOA

Answer 18

unknown

Question 19

Inhaled anesthetics: Effects

Answer 19

myocardial depression, respiratory depression, nausea/emesis, increased cerebral blood flow (decreased cerebral metabolic demand)

Question 20

Inhaled anesthetics: toxicity

Answer 20

Hepatotoxicity (halothane), nephrotoxicity (methoxyflurane), proconvulsant (enflurane), expansion of trapped gas in a body cavity (nitrous oxide.
Can cause MALIGNANT HYPERTHERMIA

Question 21

Malignant hyperthermia

Answer 21

rare, life-threatening hereditary condition in which inhaled anesthetics (except nitrous oxide) and succinylcholine induce fever and severe muscle contractions.
Tx: dantrolene

Question 22

Dantrolene: MOA and use

Answer 22

Tx for malignant hyperthermia

Blocks ryanodine Receptor

Question 23

IV Anesthetics: mnemonic

Answer 23

BBKing on Opioids PROPoses FOOLishly

Barbiturates, Benzos, Ketamine, Opioids, Propofol

Question 24

Barbiturate for IV anesthetic:

Answer 24

Thiopental

Question 25

Thiopental: MOA

Answer 25

high potency, high lipid solubility, rapid entry into brain effect terminated by rapid redistribution into tissue (skeletal muscle) and fat Decreases cerebral blood flow "hangover effect" if injected multiple times

Question 26

Thiopental: uses

Answer 26

Induction of anesthesia and short surgical procedures

Question 27

Benzodiazepines used in anesthesia:

Answer 27

Midazolam most common drug used for endoscopy | For pre-op sedation: Midazolam >> Diazepam > Lorazepam

Question 28

Most common drug used for endoscopy:

Answer 28

Midazolam

Question 29

Benzo uses in anesthesia:

Answer 29

used adjunctively with gaseous anesthetics and narcotics.

Question 30

Benzo SE in anesthesia:

Answer 30

May cause severe postoperative respiratory depression, decreased BP (tx overdose with flumazenil), and anterograde amnesia

Question 31

Ketamine: MOA

Answer 31

Arylcyclohexylamine Blocks NMDA receptors. PCP analog that acts as dissociative anesthetic.

Question 32

Ketamine: SE

Answer 32

Cardiovascular stimulant. Disorientation, hallucination, bad dreams. Increases cerebral blood flow (useful in pts @ risk for hypotension) Only modest decrease in ventilation and is potent vasodilator. Drug of abuse --> problems with urinary bladder

Question 33

Opioids used in anesthesia:

Answer 33

Morphine, fentanyl used with other CNS depressants during general anesthesia

Question 34

Propofol: uses

Answer 34

sedation in ICU, rapid anesthesia induction, and short procedures Antiemetic properties - very useful for ppl given opioids Safe for pregnant women

Question 35

Propofol: SE

Answer 35

Less postoperative nausea than thiopental | Caution in pts with high TGs, because very fatty

Question 36

Propofol: MOA

Answer 36

Potentiates GABA A

Question 37

Preferred GA for neurosurgery

Answer 37

Isoflurane

Question 38

Preferred GA for pts prone to MI

Answer 38

Sevoflurane

Question 39

IVGA used for pts at risk for hypotension

Answer 39

Etomidate

Question 40

Local anesthetics: esters

Answer 40

procaine, cocaine, tetracaine

Question 41

Local anesthetics: amides

Answer 41

lidocaine, mepivacaine, bupivacaine (amides have 2 I's in name)

Question 42

Local anesthetics: MOA

Answer 42

block Na+ channels by binding to specific receptors on inner portion of channel. Preferentially bind to ACTIVATED Na+ channels, so most effective in rapidly firing neurons. Tertiary amine locals penetrate membrane in uncharged form, then bind to ion channels as cahrged form.

Question 43

Local anesthetics: principle

Answer 43

Can be given with vasoconstrictors (usually Epinephrine) to enhance local action - decrease bleeding, increase anesthesia by decreasing systemic concentration

Question 44

Need more anesthetic in infected tissue because:

Answer 44

infected tissue is acidic, alkaline anesthetics are charged and can't penetrate membrane effectively

Question 45

Order of nerve block for local anesthetics:

Answer 45

small-diameter fibers > large diameter myelinated fibers > unmyelinated fibers Size factor predominates over myelination, such that small myelinated fibers > small unmyelnated fibers > large myelinated > large unmyelinated

Question 46

Order of sensation loss:

Answer 46

1. pain 2. temp 3. touch 4. pressure

Question 47

Local anesthetics: uses

Answer 47

minor surgical procedures, spinal anesthesia | If allergic to esters, give amides

Question 48

Local anesthetics: toxicity

Answer 48

CNS excitation, severe cardiovascular toxciity (bupivicaine), hypertension, hypotension, and arrhythmias (cocaine)

Question 49

Local anesthetic that causes severe cardiovascular toxicity:

Answer 49

Bupivicaine

Question 50

Neuromuscular blocking drugs: uses

Answer 50

Used for muscle paralysis in surgery on mechanical ventilation. Selective for motor (vs. autonomic) nicotinic receptor

Question 51

Depolarizing NMJ drugs:

Answer 51

succinylcholine

Question 52

Succinylcholine: MOA

Answer 52

strong ACh R agonist; produces sustained depolarization and prevents muscle contraction

Question 53

Reversal of Succinylcholine blockade:

Answer 53

``` Phase I (prolonged depolarization) - no antidote. Block potentiated by cholinesterase inhibitors. Phase II (repolarized but blocked; Ach Rs are available, but desensitized) - antidote consists of cholinesterase inhibitors ```

Question 54

Complications of Depolarizing NMJ drugs (succinylcholine):

Answer 54

hypercalcemia, hyperkalemia, and malignant hyperthermia

Question 55

Nondepolarizing NMJ drugs:

Answer 55

Tubocurarine, atracurium, mivacurium, pancuronium, vecuronium, rocuronium

Question 56

Nondepolarizing NMJ drugs: MOA

Answer 56

competitive antagonists - compete for ACh for receptors

Question 57

Reversal of blockade (nondepolarizing NMJ drugs)

Answer 57

Neostigmine (must be given with atropine to prevent muscarinic effects such as bradycardia), edrophonium, and other cholinesterase inhibitors

Question 58

Dantrolene MOA

Answer 58

Prevents release of Ca2+ from SR of skeletal muscle (Ryanodine receptor inhibitor)

Question 59

Dantrolene Use:

Answer 59

Tx malignant hyperthermia and neuroleptic malignant syndrome (toxicity of antipsychotic drugs)

Question 60

Baclofen: MOA

Answer 60

Inhibits GABA B Rs in spinal cord, inducing skeletal muscle relaxation

Question 61

Baclofen: use

Answer 61

muscle spasms (acute low back pain)

Question 62

Cyclobenzaprine: MOA

Answer 62

centrally acting skeletal muscle relaxant. Structurally related to TCAs, similar anticholinergic SEs

Question 63

Cyclobenzaprine: Uses

Answer 63

muscle spasms