Lecture 8 (Exam 2) - Opioid Agonists Brooke's Deck Flashcards
Opioids ____ CBF and possibly also ____.
⚠️Why should you proceed with caution with opioids and head injury?
⬇️ CBF, ICP
Bc opioids have some of the same effects a brain injury can cause. (Mask the injury); can affect wakefulness, can have miosis, ⬆️ PaCO2 levels and cross the BBB.
slide 16
What is a common S/E of opioids share with our induction agents?
Myoclonus! (with large doses)
slide 16
What is a severe S/E of opioids involving the chest & abdominal walls?
How do you treat this?
Skeletal muscle Rigidity!!! -makes it harder to ventilate them (fighting vent)
*have you ever fast pushed fentanyl?? (it will cause this)
Treat with: Naloxone or muscle relaxer (if you’re not gonna extubate) 😎
slide 16
Your pt is having an ERCP. You accidentally give an opioid to help them out. (we usually don’t)
This is why:
A common GI S/E of opioids is spasm of the Sphincter of _____.
This happens 99% with ______.
To treat the spasm, you give Nalaxone but you can also give incremental doses of _________ up to 2mg IV to not reverse the opioid effects.
If your patient had angina and was spasming, you know to give _____ bc it will help both. 😊
Sphincter of Oddi
Fentanyl 99%
Glucagon 2mg IV
Angina, too? NTG will help both the CP and spasm 😎
slide 17
Other than spasm of the Sphincter of Oddi, other GI S/E of opioids include? (💩, 🤮)
Delayed gastric emptying, n/v (from stim of the CTZ-chemoreceptor trigger zone), ⬆️ GI secretions, & constipation.
slide 17
Misc Opioid S/E
GU:
Cutaneous:
Placental:
urinary urgency!
flushing - histamine release. 🥵
neonatal depression, dependence 👶🏻
*basically a pregnant women’s worst nightmare - gotta pee, get really hot & flushed and now their baby is an addict.
Slide 18
Your patient is now requiring increased drug doses after about 25 days taking PO morphine for chronic pain. This is called ______?
Opioid receptors become desensitized & ⬇️ in number simultaneously. This is called ________?
T/F? Cross-tolerance can develop btwn all opioids?
Tolerance! (or physical dependence)
Downregulation
True!
Slide 19
In the ascending tract of pain:
How do opioids hyperpolarize neurons to make it less likely for them to fire an action potential?
How do they work on presynaptic neurons to inhibit release of NTMs?
-opioids promote K+ conductance on second order neurons = hyperpolarization.
-inhibit Ca++ conductance
slide 20 (video), pg. 390 Stoeltings
In the descending tract of pain:
What area in the brainstem has heavy Opioid receptors that can inhibit pain signaling via the medulla to the spinal cord?
PAG (periaqueductal gray)
Slide 20 (video)
In the CNS: opioids can reduce the emotional impact of pain by acting on regions such as the _______ _______ ______ to ⬆️ dopamine levels in areas like the nucleus accumbens (may lead to reinforcing qualities of the drug).
Anterior Cingulate Cortex
Slide 20 (video)
Which has a greater context-sensitive half-time, Fentanyl or Sufentanil?
Fentanyl
Slide 34
What is the analgesia dose for fentanyl?
1-2 mcg/kg IV
Slide 35
Induction dose for fentanyl?
1.5-3 mcg/kg IV 5 mins prior to induction
Slide 35
When giving fentanyl as an adjunct with inhaled anesthetics, what dose would you give?
2-20 mcg/kg IV
Slide 35
If using only Fentanyl for surgical anesthesia (Solo), what dose would be given?
50-150 mcg/kg IV
Slide 36
kids can also have fentanyl in the form of what?
A lollipop with the dose of 5 to 20 mcg/kg
Slide 36
A fentanyl patch dose can range from 75 to 100 mcg and has a steady delivery time of ….
18 hours
Slide 36
1 mg of PO Fentanyl is equal to how many mgs of Morphine?
5 mg
Slide 36
True or False: Fentanyl releases histamine
False - It does not
True or False: Fentanyl releases histamine
False - It does not
Slide 37
Fentanyl depresses which reflex, leading to bradycardia, decreased BP, and decreased cardiac output?
Carotid Sinus Baroreceptor
Slide 37
Fentanyl has synergistic effects with which two drugs discussed in lecture?
Benzos and propofol
Slide 38
How much does Fentanyl increase ICP?
6 to 9 mmHg
Slide 38
At which dose of fentanyl would you maybe get an EEG?
> 30 mcg/kg IV
Slide 38
Sufentanil is how many times more potent than fentanyl?
5 to 12 times
Slide 39
*Where are the opioid receptors found in the brain and spinal cord?
Periaqueductal gray (PAG),
Locus ceruleus,
Rostral ventral medulla (RVM),
Hypothalamus
Substantia Gelantinosa
(Slide 10)
Sufentanil is 92.5% bound to which protein?
alpha-1-acid glycoprotein
Slide 39
Where are the opioid receptors found in the spinal cord?
Interneurons and primary afferent neurons in the dorsal horn (substantia gelatinosa).
(Slide 10)
Which has a larger Vd, Alfentanil or Sufentanil?
Sufentanil
Slide 39
*Where are the opioid receptors found outside of the CNS?
Sensory neurons and immune cells.
(Slide 10)
How is Sufentanil metabolized?
Hepatic enzymes
Slide 39
What medications (discussed in class) can be used on opioid receptors that are found outside of the CNS?
Morphine and Ketorolac!
(Intraarticular morphine after knee surgery)
(NSAIDS like ketorolac can also be given through IV!)
(Slide 10)
What medications (discussed in class) can be used on opioid receptors that are found outside of the CNS?
Local anesthetics! They are directly applied die to intense analgesia!
** With L&D some places (like florida) use sufentanyl**
(Slide 10)
*Mu 1
Effects:
Agonists:
Antagonists:
Mu 1
Effects: Analgesia (supraspinal, spinal), Euphoria,
Low abuse potential, Miosis (pinpoint pupils), Bradycardia, Hypothermia, Urinary retention.
Agonists: Endorphins, Morphine, and Synthetic Opioids
Antagonists: Naloxone, Naltrexone, Nalmefene
(Slide 11)
*Mu 2
Effects:
Agonists:
Antagonists:
Mu2
Effects: Analgesia (spinal), Depression of ventilation, Constipation (marked)
Agonists: Endorphins, Morphine, Synthetic Opioids
Antagonists: Naloxone, Naltrexone, Nalmefene
(Slide 11)
*Kappa
Effects:
Agonists:
Antagonists:
Kappa
Effects: Analgesia (supraspinal, spinal), Dysphoria, Sedation, Low abuse potential, Miosis, Diuresis,
Agonists: Dynorphins
Antagonists: Naloxone, Naltrexone, Nalmefene
(Slide 11)
*Delta
Effects:
Agonists:
Antagonists:
Delta
Effects: Analgesia (supraspinal, spinal), Depression of ventilation, Physical dependence, Constipation (minimal), urinary retention
Agonists: Enkephalins
Antagonists: Naloxone, Naltrexone, Nalmefene
(Slide 11)
Which receptor produces physical dependence?
Mu2
(Slide 12)
What are the side effects of opioids on the cardiovascular system?
- Decreased SNS tone in peripheral veins!
-Decrease in venous return, CO, & BP
-Orthostatic hypotension & syncope - Decreased BP
-Due to Bradycardia or Histamine release!
-Bradycardia is also do to direct inhibition of the SA node!
-Morphine displaces histamine!
(Slide 13)
True or False!
Opioids + N20 or benzo = CV depression (CO & BP).
True!
(Slide 13)
What are the benefits we get from the the side effects on the cardiovascular system caused by opioids?
Cardioprotective from myocardial ischemia!
(Slide 13)
If your patient is being sewn up, would you give a 10 mg bolus of morphine or give it in increments?
Why?
Increments!
A bolus while displace a lot of histamine, especially if they are predisposed to it.
Giving the morphine in increments will allow you to have better control of BP and reduce the risk of a large histamine release causing hypotension. Also you will have a happy patient and a happy PACU nurse.
(Slide 13 and Dr Castillo’s Pearls of Wisdom)
You accidentally give your patient a large bolus of morphine while they are stitching him up towards the end of the case. You notice your patient is now bradycardia and hypotensive, what drugs would you want to give and in what order?
To counter act the bradycardia from narcotics you first give atropine,
If atropine doesn’t work then you can give them EPI! Not the whole 1 mg like in a code, a lesser amount! You can dilute the 1 mg dose in a 10 or 20 mL syringe and give it 1 cc at a time!
Vasopressin (40 units) would be up next! Same thing, dilute it with 10 mL and give it 0.5 to 1 cc at a time. Depending on how bad the hypotension is!
(Slide 13 and Dr Castillo’s Pearls of Wisdom)
What are the side effects of opioids with ventilation?
Decreased responsiveness of ventilation centers to CO2!
-Increase in resting PaCO2 (Shift to the right)! End tidal will need to be higher than 35-45 [~50] for the patient to start breathing!
-Going up to 60 PaCO2 will cause CO2 narcosis and the patient will be in a deeper sleep and be harder to wake up!
-Effects on mu2 receptors will cause a change in rhythm (decreased rate with compensatory increase in tidal volume), pauses, & periodic breathing!
(Slide 14)
What are signs of opioid overdose?
APNEA, Miosis, Hypoventilation & Coma
(Slide 14)
How does Physostigmine help a patient that is overdosed with opioids during a case?
It increases CNS levels of Acetylcholine (Ach) which antagonize ventilatory depression but not analgesia! You give it in increments.
(Slide 14)
If you overdose a patient with a volatile anesthetic, how can giving a narcotic be beneficial?
Volatile anesthetics cause fast and shallow breaths. Narcotics decrease rate with compensatory increase in tidal volume.
The increase in tidal volume can help blow out volatile anesthetics.
(Surfing the curve -Castillo)
(Slide 14 and Castillo’s Pearls of Wisdom)
What two drugs presented in class cause cough suppression and do not provocate the cough reflex?
- Codeine (Opioid)
- Dextromethorphan: no analgesia (It is a non-opioid derivate of morphine)
(Slide 14)
What should you be concerned with when giving a pre-induction dose of narcotics?
Reflex coughing!
(Make sure you have your suction! You do not have to get ready if you stay ready!)
(Slide 14)
What causes the elimination 1/2 time of Morphine longer?
And what organ dysfunction contributes to this?
Longer with morphine-3-glucuronide metabolites
Renal dysfunction
(slide 28)
Does Morphine exhibit a greater analgesic potency and slower speed of offset more In women or men?
Women
(slide 28)
Which 4 pt populations should we be more careful in administering Morphine due to its increased effects?
- women
-neonates
-elderly (due to decreased kidney function and protein levels)
-renal dysfunction pts
Prolonged depression of ventilation (>7 days) days has been observed in patients with renal failure after the administration of what medication?
Morphine
-pg. 407
Morphine causes hypoxic sensitivity decrease in women or men more?
Women
(morphine decreases the slope of the ventilatory response to carbon dioxide in women, whereas in men, there was no significant effect)
-pg. 407