Opiods Flashcards
What pathway inhibits the spinothalamic tract, causing pain relief?
Periaqueductal Grey - inhibits the ascending pathway
The Kappa receptor binds what endogenous opoid?
Dynorphin
What endogenous opoids bind the Mu-receptor?
Enkephalin and B-endorphin
What does the peptide pro-opoidmelanocortin get cleaved into?
B-endorphin and ACTH
What does the delta receptor bind?
Enkephalins
What receptor does Morphine bind to and what are secondary messengers?
Morphine binds the Mu-receptor, activating Gi-coupled receptor decreasing cAMP, decreasing Ca+2, inhibiting neurotrasmitter release of ascending tract.
What are the two most important qualities of an opoid dictating their effectiveness?
Lipophilicity and Elimination
Which two opoids are considered prodrugs?
Herion and Codeine
What are common effects of opiods?
- Analgesia
- Cough Suppresion
- Decreases GI Motility
- Euphoria
- Endocrine Effects, increased ADH and decreased LH
- Pupillary Constriction - no tolerance
What is the most concerning side effect of Opoids?
Respiratory Depression
- decreases sensitivity of chemoreceptors
- additive with other depressing drugs
Why would giving Morphine to someone with Gall stones cause them more pain?
Due to opoids ability to tighten sphincter tone.
Why would it be beneficial to give opoids to an individual who is having an MI?
Opoids decrease the myocardial oxygen demand, helping when there is ischemia occurring.
What are the effects of the Mu-receptor, other than inhibition of ascending pain pathways?
Decrease GI Motility
Decrease LH release
Increase ADH release
Induce Nausea in the postrema area of brain
What would you have to do if you were prescribing a pain-relieving dose of Morphine to a patient from IV to PO usage?
Multiple it by 3x, because the bioavailability is 1/3 of ingested dose.
What opoids work on the Mu-receptor?
Morphine, Heroin, Codeine, Oxycodone, Hydrocodone, Methadone, Meperidine, and Fentanyl
What drug has the highest abuse potential and is more lipophilic compared to Morphine?
Heroin
What opoid is a prodrug that is converted to Morphine and typically used in combination with Acetaminophen?
Codeine – typically more mild-moderate pain
What opoids are used for moderate-severe pain, usually combined with Tylenol?
Oxycodone and Hydrocodone
What opiod is used to treat chornic pain and/or opiod abuse?
Methadone - equal to morphine, longer duration and better bioavailability
What opiod is similar potency to Morphine, but has a shorter lasting effects and toxic metabolites?
Meperidine, toxic metabolites and interacts with MAO inhibitors.
What short acting opiod is used in transdermal patches for long lasting pain relief?
Fentanyl
What is an opiod that is about 2-3x more potent than Morphine?
Hydromorphone
What opiod is mix-action, Mu-antagonist and a Kappa-agonist?
Nalbuphine - can cause withdrawal symptoms in dependent patients. Minimal euphoria. IV use only.
What opiod can be combined with Naloxone to treat opiod dependence?
Buprenorphine
Alone what kind of effects does Buprenorphine have?
Partial Mu-agonist, used for moderate-severe pain. Less dependence forming.
If a patient overdosed on opiods what can reverse the effects immediately?
Naloxone
How does Naloxone work?
High Affinity for Mu-receptor - antagonist preventing effects. Short duration.
What is a long acting drug used for opiod and alcohol abuse?
Naltrexone
What is a NMDA receptor antagonist that is a cough suppressant?
Dextromethorphan
What does Tramadol do and what is it used for?
Tramadol is a weak Mu-receptor agonist and blocks NE/Serotonin uptake. Mild-moderate pain.
If you are tolerate to one Mu-agonist how are the other opiod Mu-agonists effected?
All Mu-agonists undergo tolerance. Cross Tolerant.
What effects do patient’s become tolerant of first?
nausea/vomiting.
Then gradually, pain relief, euphoria, respiratory depression, and endocrine effects
What effects are unphased by tolerance?
Miosis and Constipation (Suppressed GI-motility)
What are the symptoms of Opiod withdrawal?
First - restlessness, sweating, yawning
Second - piloerection, involuntary movements, n/v, depression
End effects, restless sleep and hyperactivity
Takes 7-10 Days Total - Nonlethal
