Exam 2: 24 Feb Opioid Agonist/Antagonists Flashcards
What are the two types of opioid compounds discussed?
Opioid agonists and opioid antagonists
What is the role of opioid antagonists in anesthesia?
They act as antidotes for opioid overdose and reverse opioid toxicity
What should be adjusted when administering opioids to patients on agonist-antagonists?
Opioid doses should be adjusted
What is the ceiling effect in relation to opioids?
It prevents additional responses when it comes to side effects
What are the five phases of anesthesia?
- Pre-op
- Induction
- Maintenance
- Emergence
- Post-op
What is pentazocine classified as?
An opioid agonist-antagonist
What receptors does pentazocine primarily affect?
- Delta receptors
- Kappa receptors
What is the potency of pentazocine compared to morphine?
1/5 as potent as morphine
What is nalbuphine used for in clinical applications?
Reversing opioid-induced depression
What potential side effect is associated with nalbuphine?
Dysphoria
What is the primary use of naloxone?
Reversing opioid-induced depression
What is the mechanism of action for methylnaltrexone?
Selective peripheral opioid antagonist
How does the epidural space relate to opioid administration?
It is used for drug delivery in acute and chronic pain management
What factors affect the cephalad movement of spinal anesthetics?
- Coughing
- Straining
- Body position
What are common side effects of opioids?
- Pruritus
- Nausea
- Vomiting
- Urinary retention
- Respiratory depression
True or False: Opioid agonists have a higher potential for physical dependence than agonist-antagonists.
True
Fill in the blank: The _______ effect limits the maximum effect of opioids.
ceiling
What is the elimination half-life of pentazocine?
2 to 3 hours
What is the significance of drug veracity in spinal anesthesia?
It impacts the distribution of spinal anesthetics
How does butorphanol compare to morphine in terms of dosing guidelines?
It is less potent than morphine
What is a notable side effect of naloxone?
Withdrawal symptoms
What is the dosing range for pentazocine when administered IV?
10 to 30 milligrams
What happens to heart rate and blood pressure with increased pulmonary artery pressure?
Increase in heart rate and blood pressure.
What is butorphanol commonly known as?
Stable.
What is the agonistic potency of butorphanol compared to its antagonistic potency?
Agonistic is 20 times, antagonistic is 10 to 30 times.
What is the equivalent dose of butorphanol to morphine?
2 to 3 milligrams IM is equal to 10 milligrams of morphine.
What is the elimination half-time of butorphanol?
2.5 to 3.5 hours.
What are the routes of elimination for butorphanol?
Fecal route or urine route.
True or False: Butorphanol has minimal affinity for sigma receptors.
True.
Which receptor does butorphanol have a moderate affinity for to produce analgesia?
Kappa receptor.
What is the potency of buprenorphine compared to morphine?
Buprenorphine is 50 times more potent than morphine.
What is the elimination half-time of buprenorphine?
3 to 6 hours.
What is the duration of action for buprenorphine?
8 hours.
What are the common side effects associated with buprenorphine?
Similar to other opioids, including withdrawal symptoms.
What is the primary use of naloxone?
Opioid overdose and opioid-induced depression.
What is the duration of action for naloxone?
30 to 45 minutes.
What is the typical dosage range for naloxone?
1 to 4 mcg per kg.
What side effect can occur with rapid administration of naloxone?
Pulmonary edema and cardiac dysrhythmias.
What is the elimination half-time of naltrexone?
10.8 hours.
Fill in the blank: Methyl naltrexone works primarily on the _______.
Peripheral opioid receptors.
What is the primary use of methylnaltrexone?
To promote gastric emptying.
What is the potential risk associated with long-term use of peripheral opioid antagonists?
Major cardiovascular events.
True or False: Buprenorphine is less potent than morphine.
False.
What is the effect of naloxone on analgesia when used?
It reverses analgesia.
What is the main mechanism of action for opioid antagonists like naloxone?
They bind to opioid receptors without activating them.
What type of antagonist is naloxone?
Non-selective competitive antagonist.
What is Rexone?
Rexone is an opioid formulation that combines oxycodone and naltrexone.
Why might Rexone have been pulled from the market?
It may have been pulled due to concerns related to the opioid epidemic and the involvement of Big Pharma.
What significant financial impact resulted from the opioid epidemic?
There was a payout of billions of dollars to families affected by the opioid epidemic.
What is a potential side effect of opiates related to histamine?
Histamine release may occur with opiate use.
True or False: Allergies to opiates are always due to the opiate itself.
False.
What is the effect of short-term opioid use on the immune system according to recent literature?
Short-term opioid use does not suppress the immune system.
What is the relationship between opioid use and cancer metastasis?
Long-term opioid use may be associated with increased metastasis in cancer patients.
What is the purpose of minimum alveolar concentration (MAC)?
MAC measures the efficacy of anesthetics in achieving sedation.
How does fentanyl affect MAC?
Fentanyl can decrease MAC by 70 to 90%.
What is the typical dosage of fentanyl administered before surgical incision?
3 micrograms per kilogram IV, delivered 25 to 30 minutes before surgical incision.
What is the effect of opioid agonist-antagonists on MAC?
Opioid agonist-antagonists can decrease MAC by varying percentages.
Fill in the blank: The epidural space is an _______ space where drugs can be injected.
imaginary
What defines neuraxial anesthesia?
Neuraxial anesthesia is administered via epidural or spinal methods.
What are the two primary methods of administering opioids?
Epidural and spinal (intrathecal) administration.
What must be done before injecting drugs into the epidural space?
Withdraw the syringe to check for blood return.
How do opioids affect sympathetic functions during neuraxial anesthesia?
Opioids do not produce sympathectomy.
Why might a patient be described as having a ‘walking epidural’?
They can move and walk while receiving an epidural during labor.
What is the significance of the epidural venous plexus?
It allows for systemic absorption of drugs administered in the epidural space.
What common vasoconstrictor is used in conjunction with opioids?
Epinephrine.
What is the role of diffusion in the uptake of drugs in the epidural space?
Drugs diffuse from areas of higher concentration to lower concentration.
What is the typical dosage difference between epidural and spinal opioid administration?
Epidural doses are usually 5 to 10 times higher than spinal doses.
True or False: Opioids have a significant effect on sensory block in the lower extremities.
False.
What is the impact of nitrous oxide at concentrations above 50%?
It can produce analgesic effects.
What is the relationship between opioid use and patient satisfaction in pain management?
Patient satisfaction is generally higher with PCA (patient-controlled analgesia) compared to standard opioid administration.
What is a common vasoconstrictor used in conjunction with opioids and local anesthetics in epidural anesthesia?
Epinephrine
Epinephrine is often used to keep drugs within the epidural area.
What are alternative vasoconstrictors that can be used if epinephrine is unavailable?
- Penilephrine
- Neosynephrine
These alternatives are supported by evidence despite being less commonly used.
What is the effect of adding a vasoconstrictor in epidural anesthesia on heart rate?
It can increase heart rate
Clinicians must differentiate the cause of heart rate increase (pain, medication, etc.).
Which local anesthetic is mentioned as being used in conjunction with fentanyl in epidural anesthesia?
Lidocaine
Lidocaine is frequently combined with opioids for effective pain management.
What is the typical peak effect time for fentanyl in epidural anesthesia?
20 minutes
This timing is crucial for laboring patients to manage pain effectively.
How much more effective is fentanyl compared to morphine in crossing the dura in epidural anesthesia?
800 times more effective
This significant difference impacts its clinical use in pain management.
What is the peak effect time for morphine compared to fentanyl?
Morphine peaks at 6 minutes
This rapid onset affects its use in spinal anesthesia.
What dermatomal level is associated with the nipple line?
T4
Understanding dermatomal levels is essential for effective spinal anesthesia.
What is the importance of avoiding certain dermatomal levels when administering spinal anesthesia?
To prevent affecting cardiac accelerator fibers
T1 to T4 levels are critical for maintaining cardiovascular stability.
What is the effect of coughing or straining on the movement of spinal medication?
It can increase cephalad movement
This can lead to unintended high spinal anesthesia and complications.
What does the term ‘veracity’ refer to in the context of local anesthetics?
The density of the medication
Veracity affects how the anesthetic behaves in the spinal fluid.
What type of local anesthetic is described as hyperbaric?
A medication that sinks due to its high density
Hyperbaric anesthetics are used strategically based on patient positioning.
What type of local anesthetic remains at the same level when administered?
Isobaric
Isobaric medications are commonly used in spinal anesthesia without significant positional effects.
What is the effect of positioning on the distribution of local anesthetics?
It can influence the flow and effectiveness of the medication
Proper positioning is critical for achieving desired anesthesia levels.
What is the clinical risk associated with unintended high spinal anesthesia?
Bradycardia and potential cardiac arrest
Immediate interventions may be needed to manage this complication.
What is the preferred method of assessing the effectiveness of spinal anesthesia after administration?
Using a wet alcohol sponge to test sensation
This method helps determine the level of anesthesia achieved.
What should be avoided in laboring patients to prevent complications?
Coughing or straining
This is important to ensure effective drug delivery and avoid complications during labor.
What is a key difference between epidural and spinal anesthesia in terms of drug delivery?
Epidural allows for lower doses and longer duration of action compared to spinal anesthesia
Epidurals are typically administered with opioids and local anesthetics, while spinals may require higher doses.
How long does morphine take to reach peak plasma levels after epidural administration?
10 to 15 minutes
Morphine is less lipid soluble than other opioids like fentanyl.
What is the mnemonic for remembering the cervical levels that keep the diaphragm alive?
C3 to C5 keeps the diaphragm alive
This highlights the importance of these cervical levels in respiratory function.
What is a common side effect of opioids, especially in obstetrics?
Itching
This is often due to the interaction with the trigeminal nucleus in the brainstem.
Which medication is commonly used to treat opioid-induced itching?
Propofol
Propofol works on the GABA A receptor to alleviate itching symptoms.
What could happen if an opioid is administered in excess, especially in elderly patients?
Respiratory depression
This is due to the effects on mu and kappa receptors affecting ventilation.
Fill in the blank: The treatment for opioid-induced nausea and vomiting is _______.
Naloxone
Naloxone can reverse the effects of opioids, including nausea.
True or False: Neonatal morbidity from opioids in breast milk is significant.
False
The risk is negligible, but mothers are advised not to breastfeed for 24 hours after administration.
What are the side effects of opioids that are dose dependent?
Nausea, vomiting, urinary retention, sedation
These effects depend on the dose and can vary among patients.
What can occur as a result of high spinal anesthesia?
Loss of respiratory function
This can happen if the spinal block affects the C3 to C5 levels.
Which opioid is known for having the longest duration of action when administered epidurally?
Morphine
Morphine can stay in the system for 1 to 5 hours after epidural administration.
What should practitioners be vigilant about when administering propofol for itching?
Monitoring for respiratory depression
Due to the potential for synergistic effects with other anesthetics.
What is the typical onset time for fentanyl when administered intrathecally?
20 minutes
This is compared to other opioids and their respective onset times.
What is a potential complication of opioid use in patients with prostate issues?
Urinary retention
This is due to the interaction with the sacral spinal cord.
What is the effect of gravity and position on drug movement in anesthesia?
They can increase cephalad movement of the drug
Body position can influence how drugs move within the spinal column.
What is the recommended dose of Naloxone for reversing opioid effects?
0.25 mg per kg per hour IV
This is effective in managing opioid-related side effects.
What is the risk of CNS excitation with opioid use?
Rare, but can appear as seizure-like activity
This is a differential diagnosis consideration in patients receiving opioids.
