Opioid, Opioid agonist/antagonist, antagonist Factoids

Question 1

What is the potency ratio of Sufentanil?

Answer 1

500-1000

Question 2

How do opioids provide analgesia through the CNS?

Answer 2

Inhibiting the ascending transmission of nociceptive transmission from the spinal cord AND activate pain control pathways from the midbrain

Question 3

What is the prototype opioid drug?

Answer 3

Morphine

Question 4

What is the potency ratio of Alfentanil?

Answer 4

10-20

Question 5

What opioid receptor has the largest concentration?

Answer 5

The Mu receptor has the largest concentration in the cerebral cortex, limbic system, caudate putamen, thalamus, periaqueductal grey matter and pre/post synaptic neurons in the spinal cord.

Question 6

Where is the highest concentration of Mu receptors?

Answer 6

Periaqueductal Grey Matter

Question 7

What is the potency ratio of Butorphanol (Stadol)?

Answer 7

5

Question 8

What cardiovascular effects do opioids have?

Answer 8

Bradycardia with little effect on blood pressure and dose dependent peripheral vasodilation.

Question 9

What is the most stimulating part of surgery?

Answer 9

Intubation, which means you need more drugs up front.

Question 10

What is the active metabolite of morphine and in what instance should Morphine use be avoided?

Answer 10

Morphine-6-Glucuronide (M6G) is the active metabolite that prolongs Morphines effects. It should be avoided in renal patients due to decreased elimination.

Question 11

What is the potency ratio of Codeine?

Answer 11

0.4

Question 12

What is an undesirable quality of Morphine?

Answer 12

Histamine release, it should be avoided in asthmatics and hemodynamically unstable patients.

Question 13

What is the metabolite of Meperidine (Demerol) and what’s its disadvantage?

Answer 13

Normeperidine - lowers seizure threshold

Question 14

What drug potentiates muscle rigidity in Remifentanyl use?

Answer 14

Nitrous Oxide, most significantly seen with chest wall compliance and truncal rigidity.

Question 15

What is the major benefit to Dilaudid?

Answer 15

There is no known active metabolite, good for use in renal patients.

Question 16

What opioid receptor reduces shivering, and causes dysphoria, sedation mitosis and analgesia?

Answer 16

Kappa Receptors

Question 17

What is the potency ratio of Fentanyl and Remifentanyl?

Answer 17

100

Question 18

What is unique about Fentanyl’s metabolism?

Answer 18

Fentanyl undergoes significant 1st pass effect in the lungs, however clearance is dependent on hepatic blood flow.

Question 19

Why isn’t Alfentanil widely used?

Answer 19

There is great patient to patient variability, not very predictable.

Question 20

What is the potency ratio of Buprenorphine?

Answer 20

30

Question 21

How is Remifentanyl metabolized?

Answer 21

Metabolized by non-specific blood esterases (be aware when giving to patient with cholinesterase deficiency)

Question 22

What can occur in a chronic drug user when given pain medication?

Answer 22

Down regulation of one receptor causes use of another receptor that isn’t as effective. May have to give more medication to alleviate pain.

Question 23

What opioid agonist-antagonist has the same potency as Morphine?

Answer 23

Nubaine

Question 24

How do opioids effect the eyes?

Answer 24

Parasympathetic stimulation of the oculomotor nerve causes vasoconstriction this is known as Miosis (small pupils)

Question 25

What is the most potent phenylpiperidine?

Answer 25

Sufentanil

Question 26

Meperidine (Demerol) use is contraindicated with which drug class?

Answer 26

MAOI, significant reaction and possible seretonergic crisis

Question 27

What is the potency ratio of Meperidine (Demerol)?

Answer 27

0.1

Question 28

Why aren't opioids considered anesthetics?

Answer 28

Opioids do not provide amnesia and the patient will have recall if not given another medication

Question 29

Where are Kappa receptors located in the CNS?

Answer 29

Nucleus raphe mangnus (midbrain) Hypothalamus Spinal Cord

Question 30

Which opioid receptor provides analgesia, mild constipation, urinary retention, and dependence?

Answer 30

Delta Receptors

Question 31

if a patient is not intubated, how can opioids effect ICP?

Answer 31

Opioids can increase ICP by hypoventilation which causes vasodilation and increased cerebral blood flow

Question 32

What are the effects of stimulating the Mu opioid receptor?

Answer 32

Analgesia, euphoria, sedation, dependence, respiratory depression, miosis, marked constipation, urinary rentention, bradycardia, pruritus, muscle rigidity and biliary spasm

Question 33

Where are Delta opioid receptors located in the CNS?

Answer 33

``` Olfactory centers Cerebral cortex Nucleus accembens Caudate putmen Spinal Cord ```

Question 34

True or false, respiratory depression is a very sensitive indicator of opioid effects?

Answer 34

False, respiratory depression is NOT a very sensitive indicator of opioid effects. (the respiratory drive is separate from analgesia)

Question 35

How do opioids effect the respiratory system?

Answer 35

Opioids produce dose dependent depression of ventilatory response of CO2 by directly affecting the ventilatory centers in the medulla.

Question 36

What cardiovascular mechanisms are not effected by opioid agents?

Answer 36

Opioids have no effects on myocardial contractility, baroreceptor reflexes and autonomic responsiveness.

Question 37

What causes generalized hypertonus that is associated with high dose opioids?

Answer 37

Mu receptors and dopamine and GABA pathways

Question 38

What drugs can relieve the muscle rigidity associated with opioids?

Answer 38

Relieved by muscle relaxants and antagonists (succinylcholine)

Question 39

What is the least lipophilic opioid agent?

Answer 39

Morphine

Question 40

Why is Codeine thought to be a weak opioid?

Answer 40

10% is converted to morphine

Question 41

What opioid is structurally similar to atropine?

Answer 41

Meperidine (Demerol) has antispasmodic properties

Question 42

What opioid can be given post operatively to reduce shivering?

Answer 42

Meperidine (Demerol), works at the Kappa receptors

Question 43

What opioid is the most lipid soluble?

Answer 43

Sufentanil

Question 44

Why shouldn't we bolus Remifentanil?

Answer 44

Increased risk for muscle rigidity, limits bolus dosing

Question 45

What opioid can not be used in an epidural?

Answer 45

Remifentanil, it causes glycine neurotoxicity

Question 46

Define Agonist

Answer 46

Drugs that occupy a receptor and activate them

Question 47

Define Antagonist

Answer 47

Drugs that occupy receptors but do not activate them, antagonists block receptor activation by agonists.

Question 48

How do antagonists, agonists and partial agonists effect their receptor sites?

Answer 48

Agonists exhibit unlimited effect partial agonists reach maximum effect after specific dose True antagonists never exhibit the clinical effect

Question 49

What types of drugs have a ceiling effect?

Answer 49

Partial agonists

Question 50

What does a steep dose response curve indicate?

Answer 50

The drug is more responsive with higher doses, small changes in dose produce large effects

Question 51

Which drug's antagonistic affects relates to its ability to displace opioid agonists from their receptors?

Answer 51

Buprenorphine

Question 52

Which receptor site does Buprenorphine compete for?

Answer 52

Mu

Question 53

Which antagonist-agonist opioid is an agonist at the Kappa receptor and a weak antagonist at the Mu receptor?

Answer 53

Butorphanol

Question 54

Why aren't we as worried about respiratory depression in opioid agonist-antagoinist agents?

Answer 54

Respiratory depression exhibits a ceiling effect in opioid agonist-antagoinist agents

Question 55

What factors should be considered if you are using an agonist-antagonist as a primary analgesic?

Answer 55

Consider the options for rescue or further treatment of pain

Question 56

What is a non-selective antagonist at all opioid receptors?

Answer 56

Naloxone, treats opioid induced respiratory depression, pruritus and suspected drug overdose

Question 57

How should Naloxone be administered?

Answer 57

Naloxone should be given in small incremental doses because it can cause flash pulmonary edema.

Question 58

Which opioid antagonist has an active metabolite?

Answer 58

Naltrexone

Question 59

Which agonist antagonist opioid agent causes an increase in cardiovascular effects and why?

Answer 59

Butorphanol causes an increase in circulating catecholamines

Question 60

Which partial opioid agonist is very slow to dissociate from the opioid receptor?

Answer 60

Buprenorphine, there is not a rescue drug for this, should be used with caution

Question 61

Where is nociception suppressed in neuraxial opioids?

Answer 61

Lamina II and V cells of the dorsal horn of the spinal cord and Kappa receptors in the substantia gelatinosa

Question 62

What two side effects are seen more in neuraxial opioids than if the opioid was given IV?

Answer 62

Greater incidence of pruritus and urinary retention

Question 63

What is the difference between spinal anesthesia and an epidural?

Answer 63

Spinal anesthesia is injected into the CSF on the spinal cord where an epidural is placed in the potential space

Question 64

What three factors determine opioid uptake from neuraxial anesthesia?

Answer 64

Epidural fat CSF Systemic circulation of blood

Question 65

Why is it beneficial to add epinephrine to a neuraxial opioid?

Answer 65

Epi constricts the vessels decreasing blood flow and keeping the medication in the the affected area longer

Question 66

What two opioid agents are associated with early respiratory depression in neuraxial anesthesia?

Answer 66

Fentanyl and Sufentanil ( <2 hrs) central circulation

Question 67

What opioid agent is associate with delayed respiratory depression in neuraxial anesthesia?

Answer 67

Morphine ( >2hrs) ventral medulla

Question 68

What determines how fast or slow an opioid will take effect in neuraxial anesthesia?

Answer 68

Dependent on the lipid solubility of the drug

Question 69

What is the major cause of respiratory depression in neuraxial anesthesia?

Answer 69

Additional medication given because time was not allowed for epidural/spinal to work

Question 70

What is the intrathecal or subarachnoid single dose of Fentanyl?

Answer 70

5-25 mcg

Question 71

What is the intrathecal or subarachnoid single dose of Morphine?

Answer 71

0.1-0.3 mg

Question 72

What is the epidural single dose of Fentanyl?

Answer 72

50-100mcg

Question 73

What is the epidural single dose of Morphine?

Answer 73

1-5mg

Question 74

What is the epidural continuous infusion of Fentanyl?

Answer 74

25-100mcg/hr

Question 75

What is the epidural continuous infusion of Morphine?

Answer 75

0.1-1mg/hr

Question 76

What is the onset and duration of Alfentanil in comparison to fentanyl?

Answer 76

Alfentanil has a more rapid onset and a shorter duration of action than fentanyl.

Question 77

What type of surgery would warrant the use of Nalbuphene (Nubain) for post-operative pain management?

Answer 77

Brain surgery! Because it reverses sedative qualities.

Question 78

Why is continuous monitoring important after a dose of Narcan is given?

Answer 78

Because of its short half-life in comparison to opioids, respiratory depression may return once Narcan wears off.

Question 79

Which opioid agonist-antagonist is useful in the cardiovascular population?

Answer 79

Nalbuphine (Nubian)

Question 80

What adverse effects does Naloxone have on the body?

Answer 80

Nausea and Vomiting Increased SNS activity Pulmonary edema Sudden death

Question 81

What drug is often given to drug addicts to prevent the euphoric effects of the drug they abuse?

Answer 81

Naltrexone

Question 82

Why is the SNS unable to be activated during neuraxial opioid administration?

Answer 82

SNS is inhibited due to blockage of the sympathetic chain ganglia

Question 83

Where can neuraxial opioids be given?

Answer 83

Can be given via epidural and intrathecal routes