Induction Meds: Opioids Agonists Concepts Flashcards
What are opioids effects on the CO₂ medullary center?
- Opioids inhibit the CO₂ medullary center.
Differentiate opioids from narcotics.
- Opioids = all exogenous substances that bind to endogenous opioid receptors.
- Narcotic = any substance that can produce dependence (stupor)
S7
What two types of opioid chemical structures are there?
- Phenanthrenes
- Benzylisoquinolines
S8
What types of drugs are Phenanthrenes?
Morphine & codeine
S8
What is Papaverine mostly used for?
Treating intra-arterial barbiturate administration
(dilates the highly constricted artery).
S8
What portions of the brain are the source of Descending Inhibitory Signals?
- Thalamus
- PAG
- Locus Coeruleus
S9
What endogenous substances have the same effect on receptors as Opioids?
Endorphins, Enkephalins, and Dynorphines.
S10
Presynaptic inhibition of what neurotransmitters occurs with Opioid administration?
- Substance P
- ACh
- NE
- Dopamine
S10
How do Opioids modulate pain at the cellular level?
- ↑ K⁺ conductance (hyperpolarization)
- Ca⁺⁺ channel inactivation
S10
Where are Opioid receptors located in the brain?
- PAG
- Locus Ceruleus
- RVM (rostral ventral medulla)
- Hypothalamus
S11
Where is the primary site of Opioid receptors in the spinal cord?
Substantia gelatinosa (aka Laminae 2)
where local anesthetics work
S11
Where is/are Opioid receptors found outside the CNS?
Sensory neurons & immune cells
S11
What are the four (most important) types of opioid receptors?
- Μu1 (μ₁)
- Μu2 (μ₂)
- Κappa (κ)
- Delta (δ)
S12
Which opioid receptor(s) is/are responsible for respiratory depression & physical dependence?
- Μu2
- δ
S12
Which receptors are responsible for constipation?
- Μu2 (primarily)
- δ (less)
S12
Which receptors can cause urinary retention?
- Μu1
- δ (delta)
S12
All opioid receptors induce analgesia at both the brain the spinal cord. T/F?
- False. Μu2 receptors only cause at analgesia at the spinal cord level.
S12
What opioid receptors have low abuse potential when bound?
Μu1 and κ
S12
Which opioid receptor is responsible for euphoria, bradycardia, hypothermia, and miosis when bound?
Mu1
S12
What agonists bind to the four opioid receptors?
- Mu1 & Mu2 = endorphins, morphine, synthetics.
- κ = dynorphins.
- δ = enkephalins.
S12
Describe the adverse side effects of Opioids on the cardiovascular system.
- ↓SNS tone = ↓BP, VR, and CO & Orthostatic hypotension and sycope
- ↓HR + histamine release = ↓BP
+ N2O or Benzo = CV depression
S12
What possible cardiovascular benefits do Opioids provide?
Myocardial ischemia protection
(won’t cause myocardial depression)
S13
What are the respiratory effects of Opioids?
- Depressed CNS response to CO₂ causing a right shift of PaCO₂ (↑)
S14
What drug would treat opioid ventilatory depression but not reverse analgesia?
How?
Physostigmine would by increasing CNS levels of ACh
S14
What is normal PaO₂?
Normal PaO₂ is 80 mmHg
S15
What would cause a leftward shift in PaO₂?
What would cause a rightward shift?
- Leftward: Metabolic acidosis (to breathe off all that CO₂)
- Rightward: sleep → opiates → anesthesia (need higher CO2 to make them breath)
S15
Why should caution be used when administering opioids to head trauma patients?
Opioids ↓CBF and possibly ↓ICP
S16
What musculoskeletal abnormality occurs with Opioid administration?
What makes this condition worse?
How is it treated?
-Skeletal chest wall and abdominal muscle rigidity
- Mechanical ventilation makes it worse
- treat with Muscle relaxants and/or naloxone
S16
What are Sphincter of Oddi spasms?
Which drugs can cause this?
- Biliary smooth muscle spasm
caused by:
- Fentanyl (99%),
- Morphine (53%)
- Meperidine (61%).
I think maybe all opioids can cause this but these are the primary culprits
S17
What drugs should be used for ERCP cases?
- Non-opioids (multimodal approach w/ NSAIDs, gabapentin, etc.)
How are opioid-induced Sphincter of Oddi spasm’s treated?
- Naloxone
- Glucagon (2mg IV given incrementally) and causes no opioid antagonism.
How long does it take (generally) to develop tolerance to Opioids?
What causes tolerance?
- 2-3 weeks
- 25 days with Morphine
- Downregulation (↓ opioid receptors) causes tolerance
S20
What types of drugs are Benzylisoquinolines?
Papaverine
S8
Are there any receptors that cause diuresis when bound?
κ (Kappa)
S12
What are the syptoms of Opioid overdose?
- apnea
- miosis
- hypoventilation
- coma
S14
What can happen when large doses of Opioid is given?
Myoclonus
S16
What is the side effect on GU with Opioids?
urinary urgency
S19
What are the effects on cutaneous with Opioid?
flushed face, neck, & upper chest
d/t Histamine release
S19
What are the side effects on the placenta with Opioids?
- neonate depression
- dependence (chronic)
S19
What negative change can develop between all opioids?
Cross-tolerance
S20
