opioid agonists

Question 0

name some morphine derivatives

Answer 0

dilaudid (morphine with a hydroxyl group added)

heroin (morphine with two acetyl groups added)

Question 1

how do opioid agonists produce miosis?

Answer 1

opioids cause miosis (pupillary constriction) by acting on mu and kappa receptors to stimulate the Edinger Westphal nucleus of the oculomotor cranial nerve (CN3) to constrict pupils

“The Edinger–Westphal nucleus is the accessory parasympathetic cranial nerve nucleus of the oculomotor nerve (cranial nerve III), supplying the constricting muscles of the Iris.” - wikipedia

Question 2

name some phenylpiperidine derivatives

Answer 2

demerol
anything with fentanyl like sufenta, remi, etc.

most commonly used opioid agonists in anesthesia

Question 3

why can’t you use opioids as the sole anesthetic?

two reasons

Answer 3

respiratory depression

not reliable as anesthetics

Question 4

phenylpiperidines vary widely in potency, from the least potent __ to the most potent __

Answer 4

least - demerol (50mg to stop shivering)

most - sufenta (0.4 mcg/kg/min as an infusion)

Question 5

where do opioid agonists work?

Answer 5

STEREOSPECIFIC receptors sites at pre and post synaptic sites in the CNS, also outside the CNS in peripheral tissues

NON-ionized and LEVOrotary

Question 6

what is the prototypical opioid agonist?

Answer 6

morphine

Question 7

where do neuraxial opioids exert their effect?

Answer 7

mu receptors of the substantia gelatinosa in the spinal cord

Question 8

the epidural dose is usually __x greater than the subarachnoid dose

Answer 8

5-10x

Question 9

remember, neuraxial opioids are specific for __, not somatic pain

Answer 9

visceral

Question 10

epidural opioids work via mu spinal cord receptors AND __

Answer 10

systemic action

Question 11

which way do neuraxial opioids move?

is the movement greater with more or less lipid soluble opioids?

Answer 11

they move cephalad

movement is greater with LESS lipid solubles like morphine

Question 12

what’s the most common side effect of neuraxial opioids?

Answer 12

pruritis

Question 13

what is poikothermia?

Answer 13

when the body temp equilibrates with room temp

Question 14

is pruritis from histamine release?

Answer 14

NOPE, it’s due to cephalad migration in the CSF to trigeminal nucleus

treatment is narcan, antihistamines

Question 15

four main side effects of neuraxial opioids

Answer 15

pruritis, urinary retention, ventilatory depression, sedation

Question 16

how do neuraxial opioids cause urinary retention and what is the treatment?

Answer 16

opioid receptor activation in sacral spinal cord inhibits sacral parasympathetic outflow causing detrusor muscle relaxation and greater bladder capacity

reversed with narcan

Question 17

what is the MOST SERIOUS side effect of neuraxial opioids?

Answer 17

respiratory depression, 2 hours think cephalad migration in CSF interacting with ventral medulla

occurs most often with morphine, coughing, ongoing use

Question 18

sedation after neuraxial opioid is most common with __

Answer 18

sufentanil

Question 19

should you use morphine WITH preservatives in epidural/SAB?

Answer 19

no

Question 20

how do neuraxial opioids cause water retention?

Answer 20

release vasopressin

Question 21

since neuraxial opioids delay gastric emptying, if your epidural patient becomes a crash c-section, besides the fact they are a full stomach, hold ___ !

Answer 21

cricoid

Question 22

analgesia with morphine is best when given __ pain starts

Answer 22

before

Question 23

morphine has a slower peak than fentanyl due to slower penetration of the __

Answer 23

BBB

Question 24

morphine has poor CNS penetration due to high ionization, poor lipid solubility, and rapid conjugation via __ acid

Answer 24

glucuronic acid

Question 25

where and how is morphine metabolized?

Answer 25

glucuronic acid conjugation in liver and kidney, 75% changed to morphine-3 which is INACTIVE, 25% changed to morphine-6 which is GREATER analgesic than morphine

Question 26

morphine is eliminated in the __ so it has a cumulative effect in end stage renal patients

Answer 26

urine

Question 27

how does morphine drop your BP?

Answer 27

- decreased SNS tone to capacitance vessels = decr venous return - bradycardia from stimulation of vagal nuclei in medulla = decr cardiac output - histamine release

Question 28

give morphine no faster than __ mg/min

Answer 28

5 mg/min

Question 29

how do people breathe on morphine?

Answer 29

like a hibernating bear, big tidal but slow rate, net increased PaCO2 could be bad for neuro patients d/t incr ICP from incr CO2

Question 30

how to correct angina like pain caused by morphine induced spasm of biliary smooth muscle?

Answer 30

narcan, glucagon, ntg

Question 31

signs your CRNA friend may be going through morphine withdrawal

Answer 31

yawning, sweating, can't sleep, restless, cramps, N/V, diarrhea

Question 32

what was the first synthetic opioid agonist? what receptors does it work on? synthesized by Nazi chemists using cyanide and methylamine

Answer 32

meperidine/demerol

Question 33

where and how is meperidine metabolized? any metabolites?

Answer 33

hepatic metabolism, urine excretion, metabolite = nor-meperidine, has half the potency

Question 34

you're not allergic to meperidine, you're allergic to __-meperidine

Answer 34

nor-meperidine

Question 35

meperidine is 60% protein bound so has greater effects in __, __, and __ failure patients

Answer 35

elderly, malnourished, liver failure

Question 36

what opioid has the narrowest therapeutic index of all?

Answer 36

meperidine

Question 37

how does meperidine decrease post-op shivering?

Answer 37

kappa agonism

Question 38

meperidine for cough? diarrhea? cardiac?

Answer 38

no, no, no has similar structure to atropine so increases HR and heart O2 req's produces MYDRIASIS, not miosis

Question 39

fentanyl can rapidly redistribute to inactive tissues like fat and muscle, but the __ can store up to 75% of the initial dose

Answer 39

lungs

Question 40

fentanyl metabolism and metabolite

Answer 40

metabolized to nor-fentanyl - minimally analgesic urine excretion

Question 41

fentanyl dosages and responses 1-2 mcg/kg 2-20 mcg/kg 50-150 mcg/kg

Answer 41

1-2 analgesia 2-20 adjuvant to inhaled 50-150 sole anesthetic

Question 42

what are the disadvantages to using fentanyl as the sole anesthetic?

Answer 42

not reliable amnesia, post op ventilatory depression, sympathetic breakthrough, absorbed by CPB circuit

Question 43

what are the advantages to fentanyl?

Answer 43

not a myocardial depressant (but does cause bradycardia by depressing carotid sinus - could be dangerous to neonates) no histamine release supression of stress response it comes in a lollypop

Question 44

fentanyl and ICP

Answer 44

increased ICP

Question 45

sufenta is __ to __ more potent than fentanyl

Answer 45

5-10x

Question 46

sufenta metabolism and metabolite

Answer 46

dealkylation into inactive metabolites

Question 47

sufenta excretion

Answer 47

equal urine and GI

Question 48

sufenta can cause prolonged vent depression in __

Answer 48

ESRD

Question 49

how is sufenta better than fentanyl?

Answer 49

greater analgesia and less vent depression, more rapid induction, earlier emergence and extubation, minimal hemodynamic changes

Question 50

sufenta is NOT better than fentanyl in these areas

Answer 50

not perfect in blunting BP and stress response to surg, may cause chest wall rigidity, bradycardia

Question 51

remifentanyl is unique due to its __ linkage

Answer 51

ester

Question 52

how is remi metabolized?

Answer 52

ester hydrolysis

Question 53

which is more potent, remi or fentanyl?

Answer 53

equal

Question 54

how fast can steady state be reached with a remi infusion?

Answer 54

10 minutes

Question 55

does remi have active metabolites?

Answer 55

no, otherwise it would not have such a short action

Question 56

does remi last longer in pt's with liver or kidney failure?

Answer 56

nope, go ahead and use it.

Question 57

what receptor for remi?

Answer 57

mu

Question 58

what if your patient has a plasma cholinesterase difficiency, should you use remi??

Answer 58

not a problem, use it.

Question 59

your patient may develop chest wall rigidity and be unable to ventilate with remi. what should you do?

Answer 59

hypnotics or NMB

Question 60

does remi cause histamine release? | any problems with giving remi to a ESRD or liver?

Answer 60

no | no

Question 61

narcan is a pure antagonist

Answer 61

reverses opioids