Lec. 1: Narcotic Analgesics Flashcards
Name the three opioid antagonists.
Naloxone, Naltrexone, Nalmefene
Name the seven strong opioid agonists.
Fentanyl, Hydromorphone, Meperidine, Morphine, Methadone, Buprenorphine, Oxymorphone.
What opioid drug is considered the gold standard?
Morphine
Name the three opioid antitussives.
Codeine, dextromethorphan, levopropoxyphene.
Name the two moderate opioid agonists.
Codeine and oxycodone.
Name the two weak agonists.
Propoxyphene and tramadol.
Name the three mixed agonists/antagonists.
Pentazocine, Nalbuphine, and Butorphanol.
The structure of the opioid determines what five factors?
- Water or lipid solubility
- Absorption in and outside of CNS
- Onset of action/duration of action
- Affinity for receptors
- Side effects
Opium resin contains what three major alkaloids?
Morphine, codeine, and thebaine.
What happens if you change the two R groups on morphine?
Becomes an opioid antagonist.
Name the four endogenous opioid peptides.
Endorphins, Enkephalins, Dynorphins, and Endomorphins.
Name the three main opioid receptors.
Mu (µ), kappa (κ), and delta (δ).
Morphine and other pure agonists have the greatest affinity for ? receptors and lower affinity for ? and ? receptors.
- Mu
2. Kappa and delta
Beta-endorphin is released from what precursor protein?
(POMC) Propiomelanocortin
Enkephalins are made up of what two pentapeptides?
Met-enkephalin and Leu-enkephalin
Name the sequence of events caused by binding of an opioid to the receptor.
- Decreased cAMP
- Opening of K+ channels (hyper-polarization)
- Closing of Ca++ channels (inhibits release of neurotransmitters)
Dynorphin A (1-8) and dynorphin B (1-13) are produced from what?
Prodynorphin
Are the endogenous opioid peptides responsible for excitatory or inhibitory signals?
Inhibitory signals
Where are the opioid receptors (kappa, delta, mu) located?
At the 7-transmembrane domain-containing channels; coupled to heater-trimeric G-proteins.
What is ORL-1 and what does it stand for?
It is an orphan receptor that stands for Opioid receptor like-1
What are the three sites where opioid receptors can be found?
Peri-aqueductal gray, rostral-ventromedial medulla, and the dorsal horn of the spinal cord.
What two substances block pain transmission?
Norepinephrine and 5HT (serotonin)
What two pain stimuli activate the nociceptive neurons (ascending pathway)?
Prostaglandins and Substance P
Name the fast (myelinated) and slow (not myelinated) fibers involved in pain transmission.
Fast: A-delta
Slow: C
Which pain pathway is INDIRECT?
Descending pain inhibition pathway
Briefly describe the mechanism behind the descending pain inhibition pathway.
The brain sends neurotransmitters to the spinal cord and nerves the block the “pain transmitting gates.”
Where do NE and 5HT perform their action?
Spinal Cord
Pain in the orofacial region is transmitted by what four cranial nerves?
5th (trigeminal), 7th (facial), 9th (glossopharyngeal), and 10th (vagus)
Where is the relay site for the trigeminal nerve?
The nucleus caudalis, located in the medulla.
Cell damage to the orofacial region releases what four substances?
PG, substance P, bradykinin, serotonin –these activate the second neuron!
The endogenous pain system works at the peripheral, spinal, and ? sites?
Supra-spinal
Opioid receptors are present in the mainly in the ?. They are also present in the autonomic nervous system, peripheral nerves, and the GI tract where they mediate effects on ?, ?, and ?.
- CNS
- Heart rate
- Nociception
- GI motility
Where in the cerebral cortex are mu receptors found?
Striatum, hippocampus, dorsal horn, and midbrain
Where in the cerebral cortex are kappa receptors found?
Striatum, hippocampus, dorsal horn, and midbrain
Where in the cerebral cortex are delta receptors found?
Striatum, hippocampus, dorsal horn, and amygdala.
What pharmacologic function is seen at each opioid receptor?
Analgesia
What pharmacologic functions are associated with mu receptors?
Analgesia, sedation, miosis, euphoria, constipation, respiratory depression, and pruritus (itching)
What pharmacologic functions are associated with kappa receptors?
Analgeisa, sedation, miosis, dysphoria, micturition, diuresis, and hallucinations.
What pharmcologic functions are associated with delta receptors?
Analgesia, emotion/reward, and seizures (?)
***What are the prototypic ligands for mu receptors?
Morphine, methadone, and endorphin
***What are the prototypic ligands for kappa receptors?
Dynorphin A and Ethylketocyclazocine
***What are the prototypic ligands for delta receptors?
Enkephalins and Deltorphin II
Morphine acts as a agonist on the ? receptor and a weak agonist on the ? receptor.
- Mu
2. Kappa
Buprenorphine acts as a ? on the mu receptor, a ? on the kappa receptor, and a ? on the delta receptor.
- Partial agonist
- Antagonist
- Antagonist
Pentazocine acts as a ? on the mu receptor and a ? on the kappa receptor.
- Weak antagonist
2. Agonist
Nalbuphine acts as a ? on the mu receptor and a ? on the kappa receptor.
- Antagonist
2. Agonist
Naloxone acts on all receptors as a ?.
Antagonist
Name the two natural opioid drugs.
- Morphine
2. Codeine
What is the potency of morphine and codeine.
Morphine: 1.0
Codeine: 0.5
Name the 6 semi-synthetic opioid drugs.
- Diacetylmorphine
- Hydrocodone
- Oxycodone
- Hydromorphone
- Oxymorphone
- Buprenorphine
Name the four synthetic opioid drugs.
- Meperidine
- Fentanyl
- Methadone
- Tramadol
What is the potency of diacetylmorphine?
2-4