Opioids

Question 1

MOA of opioids

Answer 1

Have G protein coupled actions on neurons doing the ff:

1. Close voltage gated Ca++ channels on presynaptic terminals and reduce transmitter release
2. Open K+ channels and hyperpolarize and thus inhibit postsynaptic neurons

Question 2

Opioid side effects with minimal or no tolerance

Answer 2

Miosis
Constipation
Convulsions

Question 3

Side effects of opioids NOT mediated by opioid receptors

Answer 3

Nausea and vomiting (stimulaitaon of CTZ at 4th ventricle)
Hypotension - histamine release
Pruritus - histamine release

Question 4

Triad of opioid overdose

Answer 4

Pupillary constriction
Comastose state
Respiratory depression

Question 5

Antidote for opioids

Answer 5

Naloxone

Question 6

Opioid with shortest and longests half-lives

Answer 6

Shortest: REMIFENTANIL
(3-4 mins)
Longest: BUPRENORPHINE
(4-8 hours)

Question 7

Opioid receptor that has euphoria effect

Answer 7

Mu1

Question 8

Opioid receptor that has constipation effect

Answer 8

Mu2 (marked)

Kappa

Question 9

Opioid receptor that has dysphoria effect

Answer 9

Kappa

Question 10

Agonists of mu receptors

Answer 10

Endorphines
Morphines
Synthetic opioids

Question 11

Agonists of kappa

Answer 11

Dynorphins

Question 12

Agonists of delta

Answer 12

Enkephalins

Question 13

List the drugs: full agonists to opioid receptors

Answer 13

Morpine
Meperidine
Methadone
Hydromorphone
Oxymorphone
Fentanyl (100x more potent than morphine)
Levorphanol
Heroine

Question 14

List the drugs: weak-to-moderate agonists to opioid receptors

Answer 14

Tramadol (dual-acting)
Loperamide
Codeine (central antitussive)*
Dextrometorphan*
Oxycodone*
Hydrocodone*
Dihydrocodeine*
*partial agonists

Question 15

Mixed agonists-antagonists

Answer 15

Buprenorphine
Butorphanol
Nalbuphene
Nalorphene
Pentazocine
Levallorphan

Question 16

Antagonists to opioid receptors

Answer 16

Naloxone
Naltrexone (also used for alcohol dependence)
Nalmefene
Diprenophene

Question 17

Doesn’t cause contraction of sphincter of oddi

Answer 17

Meperidine

Good for acute pancreatitis

Question 18

NMDA receptor antagonist

Answer 18

Dextrometorphan

Question 19

List the drugs:weak agonists

Answer 19

Propoxyphene (used for opioid withdrawal, restless leg syndrome)
Levopropoxyphene
Dextropropoxyphene

Question 20

“Actually lowers seizure threshold”

Answer 20

Meperidine

Question 21

“Long half-life, so dapat admitted”

Answer 21

Methadone

Question 22

“Partial agonist , so may cause precipitation of withdrawal” (???)

Answer 22

Buprenorphine

Question 23

“Kappa agonist, di tayo masaya, dysphoria”

Answer 23

Nalbuphene

Question 24

May cause serotonin syndrome when used with SSRIs or MAOIs

Answer 24

Codeine

Dextrometorphan

Question 25

Withdrawn because of fatal cardiotoxicity

Answer 25

Propoxyphene

Group 1c antiarrhythmic activity

Question 26

Commonly used in suicides

Answer 26

Propoxyphene

Question 27

Used for opioid withdrawal states

Answer 27

Bupronorphine

Question 28

Used for post-op shivering

Answer 28

Butorphanol

Question 29

May cause seizures and delirium

Answer 29

Meperidine
(1/10th as potent compred to morphine)
*decreases seizure threshold (also tramadol)
*c/i in patients with epilepsy
*if given with MAOi -> hyperpyrexic coma
*if given with SSRI -> serotonin syndrome (also tramadol

Question 30

Most pronounced anti-shivering effect

Answer 30

Meperidine

a2 antagonism

Question 31

Used for opioid dependende

Answer 31

Methodone
(Methadone maintenance therapy)
*currently being investigated as a novel treatment for leukemia

Question 32

Will not cause miosis

Answer 32

Meperidine

D/t atropine-like effects

Question 33

Notes on tramadol

Answer 33

5-10x less potent than morphine

S/E profile vs other opioids: low tendency for respiratory abuse and low chances for developing tolerance and dependence