Neuropharm: Opioids

Front 1

types of opiate receptors

Back 1

mu, kappa, delta

Front 2

what are effects of mu receptor activation?

Back 2

analgesia, euphoria, dependence, decreased GI motility, miosis, respiratory depression

Front 3

what are effects of kappa receptor activation?

Back 3

analgesia, psychotomimesis, diuresis, miosis

Front 4

what are effects of delta receptor activation?

Back 4

analgesia, decreased GI motility

Front 5

describe the presynaptic effects of opioids

Back 5

opioids decrease the Ca2+ efflux and therefore decrease NT release

Front 6

describe the postsynaptic effects of opioids?

Back 6

opioids increase the K+ efflux and lead to membrane hyperpolarization

Front 7

what is spinal analgesia?

Back 7

opioids prevent primary afferents from releasing substance P into dorsal horn of cord

Front 8

what opioid receptors lead to analgesia?

Back 8

all of them (mu, kappa, delta)

Front 9

what opioid receptors lead to euphoria?

Back 9

just mu

Front 10

what opioid receptors lead to dependence?

Back 10

just mu

Front 11

what opioid receptors lead to decrease GI motility?

Back 11

mu, delta

Front 12

what opioid receptors lead to miosis

Back 12

mu, kappa

Front 13

what opioid receptors lead to respiratory depression?

Back 13

mu

Front 14

what opioid receptors lead to psychotomimesis?

Back 14

kappa

Front 15

what opioid receptors lead to diuresis?

Back 15

kappa

Front 16

endogenous agonists of mu receptors

Back 16

endomorphins (short polypeptides), beta-endorphin

Front 17

endogenous agonists of kappa receptors

Back 17

dynorphins

Front 18

endogenous agonists of delta receptors

Back 18

enkephalins, beta-endorphin

Front 19

what is supraspinal analgesia?

Back 19

opioid receptors are also present on CNS neurons. they have a post synaptic effect on these neurons and increase descending pathway inhibition of ascending pain signals. The signal coming from primary afferents is blocked and never reaches CNS.

Front 20

general effects of opioids

Back 20

increase tolerance to pain, decrease perception of pain, decrease reaction to pain. patient can feel pain but doesn't care.

Front 21

cardiovascular effects of mu agonists?, what happens clinically?

Back 21

vasodialation (decreased BP, decreased preload). venodialation can lead to acute pulmonary edema. also perception of dyspnea is decreased

Front 22

CNS pressure effects of mu agonists?

Back 22

the vasodialation leads to increased flow to CNS thereby increasing CSF press.

Front 23

what do mu agoninsts do to histamine levels?

Back 23

increase them

Front 24

highest potency opioids (Rolls Royces)

Back 24

morphine, merperidine, methadone

Front 25

fast acting & high potency opioid (Ferrari)

Back 25

heroin

Front 26

lower potency opioid

Back 26

hydrocodone, codeine (even less), prapoxifine

Front 27

mixed: a kappa agonist and weak mu antagonist

Back 27

pentazocine

Front 28

mixed: a kappa agonist and strong mu antagonist

Back 28

nalbuphine

Front 29

advantages to pentazocine

Back 29

much less likely to decrease respiration, abuse potential is decreased (but at high doses, both of these are not true)

Front 30

all opioids cause miosis EXCEPT for

Back 30

merperidine. because merperidine has muscarinic blocking activity. it actually causes miadriasis

Front 31

all opioid agonists decrease GI peristalsis EXCEPT

Back 31

pentazocine. it is a KAPPA agonist and weak mu blocker. kappa receptors don't decrease GI peristalsis (only mu and kappa do)

Front 32

what is diphenoxylate?

Back 32

mu receptor antagonist taken orally and poorly absorbed. used to relieve diarrhea by decreasing GI motility. little to no subjective effects (euphoria) at therapeutic doses.

Front 33

what is loperamide?

Back 33

immodium. similar to diphenoxylate, not as potent and even less chance of subjective effects (euphoria)

Front 34

when are opiate antidiarrheals contraindicated?

Back 34

most infectious diarrhea. particularly C. difficile infection because they increase risk of ileus, toxic megacolon, and sepsis.

Front 35

what do opioids do to delivery?

Back 35

they SLOW delivery by relaxing uterine smooth muscle

Front 36

what affect do opioids have on bladder, ureter, GI tract? give me a clinical consequence

Back 36

contraction. spasm. a dangerous spasm of galbladder can occur in someone with biliary tract obstruction causing biliary colic.

Front 37

what opioid should you use if you don't yet know what's causing abdominal GI pain? why?

Back 37

merperidine. since you haven't ruled out cholestasis. merperidine is also a muscarinic blocker so it DOES NOT contract galbladder

Front 38

in addition to its mu agoinst activity what does merperidine do?

Back 38

anticholinergic. it's a muscarinic blocker. this inhibits galbladder contraction

Front 39

what is the area postrema? what is its other name?

Back 39

located in reticular formation of medulla, detects chemical irritants in blood (fenestrated endothelium and no BBB). also called chemoreceptor trigger zone (CTZ). makes you nauseous and throw up.

Front 40

triad of symptoms in opioid overdose

Back 40

1) coma 2) pinpoint pupils (except merperidine) 3) respiratory depression

Front 41

how do you treat opioid overdose?

Back 41

naloxone. and respiratory support (keep them breathing)

Front 42

tolerance in opioid treatment

Back 42

very high tolerance develops with chronic use. strong cross-tolerance. BUT miosis and GI tract motility inhibition have NO tolerance

Front 43

what two opioid effects do not exhibit tolerance? which one's a particular problem.

Back 43

miosis, GI motility inhibition (that's the problem...people get VERY constipated once you have to up the dose)

Front 44

signs/symptoms of opioid withdrawl

Back 44

anxiety/tension, lacrimation, sweating, rhinorrea, goosebumps (cold turkey), yawning, muscle spasms (kicking the habbit), GI distress, pain

Front 45

when do withdrawl symptoms peak?

Back 45

36-48 hours

Front 46

methodone properties that make it good for withdrawl symptoms

Back 46

effective analgesic, efficacy PO, extended duration of action (long half life), shows persistent effects with repeat administration

Front 47

what ANS drug is used to decrease opioid withdrawl symptoms?

Back 47

clonidine. it blocks adrenergic effects of withdrawl. makes them less pronounced by blocking release of catecholamines.

Front 48

hydromorphone

Back 48

strong mu agonist (like morphine)

Front 49

oxymorphone

Back 49

strong mu agonist (like morphine)

Front 50

levorphanol

Back 50

strong mu agonist (like morphine)

Front 51

merperidine

Back 51

strong mu agonist and an anti-muscarinic

Front 52

fentanyl

Back 52

short acting mu agonist IV agent used for general anesthesia (transdermal fentanyl patches used in cancer pain)

Front 53

heroin

Back 53

rapidly penetrates BBB, strong acting mu agonist

Front 54

codeine

Back 54

methylated form of morphine. weak agonist because must be demethylated to be active. dependence is uncommon. less first-pass metabolism than morphine (better PO)

Front 55

dextromethorophan

Back 55

enantiomer of a methylated opioid. no analgesic or addictive properties but is an anti-tussive

Front 56

propoxyphene, tramdol

Back 56

similar to codeine (low abuse potential)

Front 57

oxycodone, hydrocodone

Back 57

potent opioids given with aspirin, acetaminophen, or ibuprofen. they have high potential for abuse (especially oxycontin which has long half life)

Front 58

side effect of diphenoxylate / loperamide

Back 58

if treating salmonella diarrhea, then you increase risk of chronic salmonella carriage

Front 59

what do rifampin and phenytoin do to metabolism of methadone? why?

Back 59

accelerate metabolism and can precipitate withdrawl symptoms. because they are cytochrome p450 inducers