Opioid Analgesics Flashcards Preview

Pharmacology > Opioid Analgesics > Flashcards

Flashcards in Opioid Analgesics Deck (40):
1

what are the major classes of opioid receptors and where do most opioid analgesics work

- μ, δ and κ.

-most work at the μ receptor

2

what are opioids action on neurons

-close voltage gated Ca channels on presynaptic nerve terminals --> reduced neurotransmitter release

-open K channels --> hyperpolarizing and inhibiting postsynaptic neurons

3

opioids reduce the release of large numbers of neurotransmitters. what are the neurotransmitters?

NAGSS

-norepinephrine
-acetylcholine
-glutamate
-serotonin
-substance P

4

where does the analgesic effects of opioids come from (aka what is the mechanism that leads to analgesia)

-directly inhibits ascending transmission of nociceptive info from spinal cord dorsal horn

-indirectly activates pain inhibitory circuits

5

receptors that opioids work on in spinal analgesia and the mechanism

-μ, δ and κ.

-inhibits the release of excitatory neurotransmitters substance P and glutamate from these primary afferents

-also inhibits the dorsal horn pain transmission neuron directly

6

receptors that opioids work on in supraspinal analgesia and mechanism

-μ, δ and κ.

-activation of pain inhibitory descending neurons

7

mechanism of peripheral analgesia

-stimulation of peripheral μ receptors by opioids decrease sensory neuron activity and release

8

what are the mixed agonists-antagonists of opioids (what do they agonize and antagonize)

Pentazocine
Butorphanol
Nalbuphine
Buprenorphine - partial μ agonist and κ antagonist

partial agonist/antagonist of μ receptors and are agonists of κ receptors

9

what are the opioid antagonist and what receptors do they antagonize

antagonize all - μ, δ and κ

naloxone and naltrexone

10

what are the opioid agonist

Morphine
Fentanyl
Meperidine
Methadone
Codeine

11

might need this box later

thanks

12

what are the CNS effects of opioids

-analgesia
-euphoria
-sedation and drowsiness
-respiratory depression
-cough suppression
-miosis
-truncal rigidity
-nausea and vomiting

13

peripheral effects of opioids

-hypotension
-GI effects: constipation
-Biliary Colic
-Decreased renal flow
-Uterus: prolongs labor
-Release of ADH, PRL, Somatotropin and inhibit LH
-Pruritis

14

how are opioids excreted

turned to metabolites mostly glucuronides then excreted by the kidney

15

what types of patients should be monitored when given opioids like morphine

those with renal impairment since it is conjugated to a glucuronide then excreted by the kidney

16

how are opioids like heroin and remifentanil metabolized

they are hydrolyzed by tissue esterases

17

which opioids causes seizures if in high concentration and what type of patients experience these seizures

normeperidine

patients with decreased renal function since it cannot be excreted hence --> seizures

18

clinical uses of opioid analgesics

5 As

-Analgesia: pain
-Acute pulmonary edema: relieves dyspnea by reducing cardiac preload and afterload
-Antitussives: relieve cough
-Antidiarrheals
-Anesthesia: sedative, anxiolytic, and analgesic properties

19

adverse effects of opioids

MAIN ONES:
nausea
vomiting
sedation
itching
constipation

IN ADDITION:
urinary retention
hypotension
respiratory depression

20

contraindications/cautions in opioid therapy

-using pure agonists with partial: diminishes effect
-head injury: CO2 retention caused by respiratory depression --> cerebral vasodilation
-pregnancy: fetus becomes dependent and experiences withdrawal postpartum
-impaired pulmonary function: opioids respiratory depressive properties --> acute respiratory failure
-decreased renal function: can't excrete it so leads to problems associated with high conc
-endocrine disease: adrenal insufficiency or hypothyroidism can have prolong and exacerbated response

21

drug interactions of opioids

-with sedative hypnotics --> resp depression
-antipsychotics --> increases sedation
-MAOI: meperidine and tramadol --> excitement, muscle rigidity, hyperthermia, unconsciousness

22

strong opioid agonists

Morphine, Hydromorphine, Oxymorphine
Heroin
Meperidine
Fentanyl
Methadone
Levorphanol

23

affinity of morphine towards opioid receptors

high affinity towards μ receptors
lower affinity towards δ and κ

24

how is heroin hydrolyzed and explain which is more liposoluble and its importance

heroin --> 6-monoacetylmorphine (6-MAM) --> morphine

heroin and 6-MAM are more liposoluble hence enter the brain more readily

25

what are primarily μ receptor agonists

Fentanyl, Meperidine, Methadone

26

who is meperidine contraindicated in and why

-people with tachycardia because it has antimuscarinic effets

-those on MAOI/serotonergic agents because it can cause serotonin syndrome due to it blocking neuronal reuptake of serotonin

27

what happens with large doses of meperidine given in short intervals

produce tremors, muscle twitches, DILATED PUPILS, hyperactive reflexes, convulsion

28

mechanism of methadone (and its difference from morphine)

μ receptor agonist
NMDA receptor antagonist
serotonin and norepinephrine reuptake inhibitor

29

drug used for opioid abstinence syndrome or treatment of heroin users in those with withdrawal symptoms and why?

methadone

-less euphoria
-longer half life and though it prolongs the abstinence syndrome, it is less severe than short acting opiates like heroin

30

what are the mild to moderate opioid agonist

Codeine, oxycodone, hydrocodone
Tramadol

31

mechanism of codeine's analgesic effect

it is converted to morphine by CYP2D6

32

mechanism of tramadol and use

weak μ agonist
norepinephrine and serotonin reuptake inhibitor

used for neuropathic pain (pain from injury to nervous system)

33

contraindication of tramadol

taken it with serotonergic agents like MAOIs because of its inhibition of serotonin reuptake and hence can lead to serotonin syndrome

34

adverse effects of mixed agonist-antagonist opioid analgesics(name them)

pentazocine, butorphanol, and nalbuphine are associated with psychotomimetic effects (not as common in buprenorphine)

35

uses of opioid antagonists analgesics (name them)

naloxone and naltrexone

naloxone - acute opioid overdose

naltrexone - decrease craving for alcohol in chronic alcoholics (longer duration than naloxone)

36

what are the antitussives

dextromethorphan
codeine

37

contraindication of antitussives

adverse effects/differences in the antitussives

do not give to those on MAOIs

dextromethorphan has no analgesic effect so it is preferred and less likely to have constipation

38

opioid anti motility agents/ antidiarrheals and are they agonists or antagonists

they are opioid agonists

diphenoxylate and loperamide

39

what does commercial use of diphenoxylate contain that discourages overdosage

atropine (antimuscarinic - might contribute to antidiarrheal action)

40

adverse effects of diphenoxylate

higher doses can cause CNS effects

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