Neuro - sedatives

Question 1

Barbiturates

Answer 1

Phenobarbital; Pentobarbital; Thiopental; Secobarbital

Question 2

MOA of barbiturates

Answer 2

Facilitate GABA-A action by increasing duration of chloride channel opening; thus decreasing neuron firing; Contraindicated in porphyria; Used as a sedative for anxiety; seizures; insomnia; and induction of anesthesia (thiopental)

Question 3

Side effects of barbiturates

Answer 3

Respiratory and cardiovascular depression (can be fatal); CNS depression (can be exacerbated by EtOH use); Dependence; Drug interactions (induces cytochrome P-450); Overdose treatment is supportive (assist respiration and maintain BP)

Question 4

Benzodiazepines

Answer 4

Diazepam; Lorazepam; Triazolam Temazepam Oxazepam Midazolam Chlordiazepoxide Alprazolam

Question 5

MOA of benzodiazepines

Answer 5

Facilitate GABA-A action by increasing frequency of chloride channel opening; Decrease REM sleep; Most have long half lives and active metabolites; Exceptions - triazolam; oxazepam; and midazolam are short acting - higher addictive potential; Used in anxiety; spasticity; status elipticus (lorazepam and diazepam); detoxification (especially alcohol withdrawal-DTs); night terrors; sleepwalking; general anesthetic (amnesia; muscle relaxation); hypnotic (insomnia)

Question 6

Side effects of benzodiazepines

Answer 6

Dependence; Additive CNS depression effects with alcohol; Less risk of respiratory depression and coma than with barbiturates; Treat overdose with flumazenil (competitive antagonist at GABA benzodiazepine receptor)

Question 7

ZolpidemZaleplonEszopiclone

Answer 7

Nonbenzodiazepine hypnoticsAct via the BZ1 subtype of the GABA receptorEffects reversed by flumazenilUsed to treat insomnia

Question 8

Side effects of zolpidem; zaleplon; and eszopiclone

Answer 8

Ataxia; headaches; confusionShort duration because of rapid metabolism by liver enzymesUnlike older sedative-hypnotics; cause only modest day-after psychomotor depression and few amnestic effectsDecreased dependence risk than benzodiazepines

Question 9

Inhaled anesthetics

Answer 9

HalothaneEnfluraneIsofluraneSevofluraneMethoxyflurane**Nitrous Oxide

Question 10

Effects of inhaled anesthetics

Answer 10

Myocardial depressionRespiratory depressionNausea/emesisIncreased cerebral blood flow**Decreased cerebral metabolic demand

Question 11

Side effects of halothane

Answer 11

Hepatotoxicity

Question 12

Side effects of methoxyflurane

Answer 12

Nephrotoxicity

Question 13

Side effects of enflurane

Answer 13

Proconvulsant

Question 14

Side effects of nitrous oxide

Answer 14

Expansion of trapped gas in a body cavity

Question 15

Malignant Hyperthermia

Answer 15

Rare; life-threatening hereditary condition in which inhaled anesthetics (except nitrous oxide) and succinylcholine induce fever and severe muscle contractions Treatment is dantrolene.

Question 16

Nitrous Oxide

Answer 16

Inhaled anesthetic Low blood solubility; Low lipid solubility; Low blood solubility provides rapid induction and recovery time; Low lipid solubility means it has low potency

Question 17

Halothane

Answer 17

Inhaled anesthetic; High blood solubility; High lipid solubility; High lipid solubility means it is highly potent; High blood solubility means there is slow induction and recovery

Question 18

Thiopental

Answer 18

Intravenous Anesthetic - Barbiturate; High potency; high lipid solubility; rapid entry into brain; Used for induction of anesthesia and short surgical procedures; Effect terminated by rapid redistribution into tissue and fat; Decreases cerebral blood flow

Question 19

Midazolam

Answer 19

Intravenous Anesthetic - Benzodiazepine; Most common drug used for endoscopy; Used adjunctively with gaseous anesthetics and narcotics; May cause severe postoperative respiratory depression; decrease in BP; and anterograde amnesia; Treat overdose with flumazenil

Question 20

Ketamine

Answer 20

Intravenous Anesthetic - Arylcyclohexylamines; PCP analog that acts as dissociative anesthetic; Blocks NMDA receptors; Cardiovascular stimulant; Causes disorientation; hallucination; and bad dreams; Increases cerebral blood flow

Question 21

Morphine and fentanyl

Answer 21

Opiods used with other CNS depressants during general anesthesia

Question 22

Propofol

Answer 22

Intravenous anesthetic; Used for sedation in the ICU; rapid anesthesia induction; and short procedures.; Less postoperative nausea than thiopental; Potentiates GABA-A

Question 23

Esters - local anesthetics

Answer 23

Procaine; Cocaine; Tetracaine

Question 24

Amides - local anesthetics

Answer 24

Lidocaine; Mepivacaine; Bupivacaine

Question 25

MOA of *local anesthetics*

Answer 25

*Block sodium channels by binding to specific receptors on the inner portion of the channel*;Preferentially bind to activated sodium channels; so most effective in rapidly firing neurons;*Tertiary amine local anesthetics penetrate membrane in uncharged form; then bind to ion channels as charged form*

Question 26

Side effects of *local anesthetics*

Answer 26

*CNS excitation*; Severe cardiovascular toxicity (bupivacaine); Hypertension; Hypotension; Arrhythmias (cocaine)

Question 27

*Succinylcholine*

Answer 27

*Depolarizing Neuromuscular Blocking Drug*; *Strong ACh receptor agonist - produces sustained depolarization and prevents muscle contraction*; Reversal of blockade: Phase I (prolonged depolarization) - no antidote - block potentiated by cholinesterase inhibitors. Phase II (repolarized but blocked; ACh receptors are available; but desensitized) - antidote consists of cholinesterase inhibitors

Question 28

Side effects of *succinylcholine*

Answer 28

*Complications include: Hypercalcemia + Hyperkalemia; *Malignant Hypertension*

Question 29

*Nondepolarizing neuromuscular blockers*

Answer 29

*Tubocurarine; atracurium; mivacurium; pancuronium; vecuronium; rocuronium*; Competitive antagonists - compete for ACh for receptors; *Reversal of blockade - neostigmine; edrophonium; and other cholinesterase inhibitors*

Question 30

*Neostigmine*

Answer 30

*Cholinesterase Inhibitor*; Used to reverse neuromuscular blockade with nondepolarizing blockers; *Must be given with atropine to prevent muscarinic effects such as bradycardia*

Question 31

*Dantrolene*

Answer 31

*Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle*; Used to treat malignant hyperthermia and neuroleptic malignant syndrome (a toxicity of antipsychotic drugs)