Opioids

Question 1

What are the types of opioids

Answer 1

endorphins, Enkephalins, and Dynorphins

Question 2

What is POMC

Answer 2

it is a precursor for ACTH, MSH, beta lipoprotein, endogenous opioids. cleaved into subunits that are pharmacologically active.

Question 3

What are the opioids receptors

Answer 3

are G-coupled receptors found in the brain, spinal cord and the digestive tract. activation of opioid receptors reduces pain transmission and produces other characteristic effects.

Question 4

What are the types of opioid receptors

Answer 4

Mu, Kappa and Delta

Question 5

What is the function of Mu

Answer 5

responsible for most of the effects and side effects of opiates, euphoria, respiratory, depression,sedation, miosis, dependence, constipation.

Question 6

What has the highest affinity with Mu?

Answer 6

Endorphins and enkephalin

Question 7

what are the full agonist?

Answer 7

Morphine, Meperidine, Fentanyl and analogues, oxycodone and Hydrocodone, Oxymorphone, methadone

Question 8

What are the antagonist?

Answer 8

Naloxone, Naltrexone and Nalmephene

Question 9

What is the function of Kappa-

Answer 9

spinal analgesia, anticonvulsant effect, depression, sedation, dysphoria and hallucination, and inhibition of ADH secretion. found in the limbic system, spinal cord, brainstem and hypothalamus

Question 10

What are the main endogenous agonist for Kappa?

Answer 10

Dynorphins (Nalbuphine and Pentazocine)

Question 11

What is the function of the Delta?

Answer 11

responsible for analgesia, antidepressant, dependence, convulsions. inhibits motility of gastro-intestina

Question 12

What has the highest affinity for delta receptors?

Answer 12

enkephalins. found in the factory bulb, nucleus accumbent and cerebral cortex

Question 13

What is the mechanism of the opioid receptors

Answer 13

stimulation of opioid receptor lead to their effect through mobilization of the alpha and the beta gamma subunit of the trimeric G protein. they beta-gamma subunit leads to opening of G protein inward rectifying potassium channels.
also inhibits adenylate cyclase, voltage gated Ca+ channels, activation of MAP kinases and Phospholipase C.
it inhibits the release of NTS from the presynaptic neuron by inhibition of the calcium influx. inhibits the depolarization of the post synaptic neurons by causing hyper polarization through opening of inward rectifying potassium channels.

Question 14

What NTS are inhibit through the G-proteins

Answer 14

decrease the release of Glutamate, substance, ACh, NE and Serotonin

Question 15

What is morphine

Answer 15

it is agonist for Mu receptor that acts at laminae I and II of the dorsal horn. important points are depresses cough reflexes, decreased peristalsis, emesis, induce histamine release. vasodilation, increased biliary pressure.

Question 16

What are the ADR of Morphine

Answer 16

Apnea and severe respiratory depression, constipation, vomiting, Urticaria, addiction. signs of acute toxicity: pinpoint pupil, respiratory depression and coma

Question 17

What manages the ADR of Morphine

Answer 17

IV Naloxone

Question 18

What is Mepheridine?

Answer 18

it is also called pethidine that binds to both Mu and Kappa receptors. it functions in increased sympathetic stimulation ( Interaction with MAO)

Question 19

What is Normeperidine

Answer 19

it is the metabolite of meperidine and it is an inhibitor of serotonin re-uptake. can change seizures, hyperactive reflexes and tremors

Question 20

What is methadone?

Answer 20

it is an antagonist of NDMA receptor. it is a agonist at Mu receptors that is potent and long duration analgesia. used to manage opioid withdrawals symptoms

Question 21

What are the synthetic opioids

Answer 21

Fentanyl- 100x more potent than morphine
Alfentanyl - 10x more potent
Sufentanyl - 1000x more potent

Question 22

What are semisynthetic opioids?

Answer 22

hydrocodone, oxycondone, hydromprohpne, oxymorphone, codeine, propoxyphene. metabolized by CYP3A4 and other enzymes

Question 23

What are partial agonist?

Answer 23

ex. Buprenorphine. it is useful only in weak pain due to it partial agonist effects. it treats addiction through suboxone - that is a combination of bupreorphine and naloxone.

Question 24

What are mixed agonist/ antagonist?

Answer 24

ones that work on one receptor but not another. doesn’t cause too much respiratory depression, ceiling analgesic effect and causes psychoactive effects.

Question 25

What are examples of an mixed agonist and antagonist

Answer 25

ex. Pentazocine- agonist at kappa and antagonist at Mu receptor
Nalbuphine and butorphanol - antagonist to Mu but agonist to Kappa

Question 26

What is loperamide

Answer 26

synthetic opioid receptor agonist and acts on the u-opiod receptors in the enteric plexus of the large intestine to treat diarrhea.

Question 27

What is dextromethorphan?

Answer 27

Dextromethorphan. Antitussive. μ, δ, and κ-opioid receptor agonist. Also, a nonselective serotonin reuptake inhibitor. Its major metabolite, dextrorphan, is an NMDA receptor antagonist.

Question 28

What is tramadol

Answer 28

weak analgesic that acts partially at mu receptors but also blocks reuptake of NE and 5-HT.Contraindicated with MAOIs. Much less addictive potential

Question 29

What is tapentadol

Answer 29

–synthetic weak analgesic similar to Tramadol. Works at mu receptors and also NE reuptake inhibitor .