Opioids

Question 1

What is nociception?

Answer 1

The neural processing of particular sensory information that results in pain perception.

Question 2

Name the four processes involved in nociceptive pain.

Answer 2

Transduction Transmission Perception Modulation.

Question 3

What stimuli activate TRPV1 and TRPV2 receptors?

Answer 3

Thermal stimuli (>42°C), low extracellular pH, vanilloid chemical ligands such as capsaicin.

Question 4

Which ion channels are activated by mechanical stimuli?

Answer 4

ASIC, ATP sensitive P2X P2Y and kinin-sensitive B1 or B2 receptors.

Question 5

What is the role of voltage-gated sodium channels in nociceptive transmission?

Answer 5

They convert depolarization of the peripheral terminal into an action potential.

Question 6

What neurotransmitters are released by primary afferent neurons in the dorsal horn?

Answer 6

Glutamate Substance P CGRP.

Question 7

How do gabapentin and pregabalin affect nociceptive transmission?

Answer 7

They modulate CNS transmission by acting on the α2δ subunit of Ca channels.

Question 8

What are the major inhibitory neurotransmitters in the dorsal horn of the spinal cord?

Answer 8

Opioid peptides norepinephrine serotonin glycine GABA.

Question 9

What is placebo analgesia?

Answer 9

Reduced sensation of pain due to belief in receiving a pain-suppressing drug involving endogenous opioid peptides.

Question 10

What are the primary clinical uses of opioids?

Answer 10

Relief of severe pain treatment of major diseases trauma and surgery.

Question 11

What receptors do endogenous opioid peptides primarily act on?

Answer 11

Dynorphins on κ-receptors, enkephalins and β-endorphin on μ and δ receptors.

Question 12

How do opioids cause hyperpolarization of nerve cells?

Answer 12

By interacting with opioid receptors increasing K efflux and reducing Ca influx.

Question 13

What effect does morphine have on the release of substance P?

Answer 13

It decreases its release modulating pain perception in the spinal cord.

Question 14

What is opioid-induced hyperalgesia (OIH)?

Answer 14

Paradoxical increase in pain sensitivity due to excessive opioid use.

Question 15

How is respiratory depression caused by opioids?

Answer 15

By reducing the sensitivity of respiratory center neurons to CO2.

Question 16

What is the primary cause of death in acute opioid overdose?

Answer 16

Respiratory depression.

Question 17

How do morphine and codeine suppress the cough reflex?

Answer 17

By unknown mechanisms independent of their analgesic effects.

Question 18

What characteristic effect does morphine have on pupils?

Answer 18

Miosis (pupillary constriction) through stimulation of μ and κ receptors.

Question 19

What effect does morphine have on the gastrointestinal tract?

Answer 19

Decreases motility increases tone of smooth muscle relieves diarrhea and causes constipation.

Question 20

How does morphine affect the cardiovascular system at high doses?

Answer 20

Causes hypotension and bradycardia due to medullary action.

Question 21

What effect does histamine release from morphine have?

Answer 21

Bronchoconstriction, hypotension, urticaria.

Question 22

Name two opioid antagonists.

Answer 22

Naloxone and Naltrexone.

Question 23

What is the primary use of opioid antagonists?

Answer 23

Treatment of opioid overdose.

Question 24

How do opioid receptors generally affect ion channels?

Answer 24

Increase K efflux reduce Ca influx leading to hyperpolarization and reduced transmitter release.

Question 25

What is the mechanism of action of μ-opioid receptor agonists in the spinal cord?

Answer 25

Decreasing the release of substance P and inhibiting excitatory transmitter release.

Question 26

What is the clinical significance of morphine's effect on the biliary tract?

Answer 26

Increases pressure due to gall bladder contraction and biliary sphincter constriction contraindicated in biliary colic.

Question 27

What are the pharmacological actions of strong opioid agonists like morphine?

Answer 27

Analgesia, euphoria, sedation, respiratory depression, cough suppression, miosis, nausea, constipation.

Question 28

How do moderate/low opioid agonists differ from strong agonists?

Answer 28

They are less potent and often used in combination with other analgesics.

Question 29

What are the effects of mixed agonist-antagonist opioids?

Answer 29

Provide analgesia with a lower risk of dependence and respiratory depression.

Question 30

Name a partial opioid agonist.

Answer 30

Buprenorphine.

Question 31

What is the role of endogenous opioid peptides in pain modulation?

Answer 31

Inhibit synaptic transmission and are released in response to noxious stimuli.

Question 32

How does naloxone reverse opioid effects?

Answer 32

By blocking opioid receptors reversing respiratory depression and analgesia.

Question 33

What is the clinical use of methadone?

Answer 33

Treatment of opioid dependence and chronic pain management.

Question 34

What is the effect of opioid agonists on the cough reflex?

Answer 34

Suppress the cough reflex with codeine being a common antitussive.

Question 35

What is tramadol and its dual mechanism of action?

Answer 35

A weak centrally acting opioid that also inhibits norepinephrine and serotonin reuptake.

Question 36

What are the primary symptoms of opioid withdrawal?

Answer 36

Agitation anxiety muscle aches increased tearing insomnia runny nose sweating yawning.

Question 37

How is acute opioid toxicity managed?

Answer 37

Administering opioid antagonists like naloxone and supportive care.

Question 38

What is the function of the nociceptive pathway?

Answer 38

Processing and transmitting pain signals from the periphery to the brain.

Question 39

Name two novel opioids.

Answer 39

Oliceridine and PZM21.

Question 40

How does opioid use affect fertility in females?

Answer 40

Inhibits cilia motility in the ovary tubes potentially leading to sterility.

Question 41

What are the effects of opioids on the respiratory system?

Answer 41

Respiratory depression and increased risk of hypoxia.

Question 42

What is the primary effect of kappa opioid receptor activation?

Answer 42

Analgesia at the spinal level sedation miosis dysphoria hallucinations.

Question 43

What is the action of dynorphins?

Answer 43

Primarily act on κ-receptors modulating pain and emotional responses.

Question 44

How do opioids influence neurotransmitter release?

Answer 44

Inhibit release by hyperpolarizing nerve terminals and reducing calcium influx.

Question 45

What is the role of naloxone in opioid overdose?

Answer 45

Reverses opioid-induced respiratory depression and other effects.

Question 46

How do serotonin and norepinephrine influence pain perception?

Answer 46

They modulate descending inhibitory pathways affecting pain transmission.

Question 47

What is the role of endogenous opioids in stress response?

Answer 47

They modulate pain and stress responses through receptor activation.

Question 48

What is the clinical use of buprenorphine?

Answer 48

Management of opioid dependence and moderate to severe pain.

Question 49

How do opioids affect gastrointestinal motility?

Answer 49

Decrease motility and increase smooth muscle tone leading to constipation.

Question 50

What is the primary mechanism of opioid-induced euphoria?

Answer 50

Stimulation of the ventral tegmentum and μ receptors.

Question 51

How does opioid use lead to respiratory depression?

Answer 51

Reduces the sensitivity of respiratory center neurons to CO2.

Question 52

What is the effect of opioid antagonists like naloxone on placebo analgesia?

Answer 52

Reduce placebo analgesia by blocking endogenous opioid peptides.

Question 53

What is the role of μ-opioid receptors in pain relief?

Answer 53

Mediating analgesia euphoria sedation respiratory depression and dependence.

Question 54

How do opioids cause sedation?

Answer 54

By additive effects with other CNS depressants and influencing neurotransmitter release.

Question 55

What are the primary side effects of opioid use?

Answer 55

Constipation nausea vomiting respiratory depression euphoria miosis.

Question 56

How is opioid-induced constipation managed?

Answer 56

Using laxatives stool softeners or opioid receptor antagonists specific to the gut.

Question 57

What is the clinical significance of morphine's effect on the anal sphincter?

Answer 57

Increases tone leading to potential urinary retention especially in intoxicated patients.

Question 58

How do opioids affect histamine release?

Answer 58

Trigger release from mast cells causing bronchoconstriction hypotension and urticaria.

Question 59

What is the effect of opioids on the cardiovascular system at therapeutic doses?

Answer 59

Minimal effect but high doses can cause hypotension and bradycardia.

Question 60

What is the role of enkephalins in pain modulation?

Answer 60

Act on μ and δ receptors modulating pain and stress responses.

Question 61

How do opioids interact with G-protein coupled receptors?

Answer 61

Inhibit adenylyl cyclase activate MAP kinase pathways and influence ion channel activity.

Question 62

What is the clinical use of fentanyl?

Answer 62

Management of severe pain often in surgical or chronic pain settings.

Question 63

How do opioids cause euphoria?

Answer 63

Through stimulation of μ receptors and the ventral tegmentum.

Question 64

What are the effects of opioid-induced hyperalgesia?

Answer 64

Increased sensitivity to pain despite opioid use.

Question 65

How does naloxone affect opioid-induced respiratory depression?

Answer 65

Reverses it by blocking opioid receptors restoring normal respiratory function.