Analgesics Flashcards
T/F: They used to think Neonates could not feel pain
True :-(
Name the 2 categories of Analgesics
Opioid
Non-Opioid
There are 2 types of Opioids. What are they?
Naturally Occurring Agents (Opium Alkaloids)
Synthetic Opioid Agonists
What do Synthetic Opioid Agonists do?
Elicit Morphine-like activity
Name the 7 Synthetic Opioid Agonists mentioned in lecture
- Codeine
- Oxycodone
- Methadone
- Morphine
- Hydromorphone
- Meperidine
- Fentanyl
What is the Mechanism of Action of Analgesics?
Activation of receptors within the CNS.
How is Analgesia Obtained?
By spinal or Supraspinal activation of Opioid Receptors—>Decreased Neurotransmitter release from Nociceptive/Sensory Neurons (Altering perception and response to pain).
Do Opioid Receptors exist outside the CNS?
Yes
Where are Opioid Receptors outside of the CNS?
The Dorsal Root Ganglia and in the terminals of Primary Afferent Neurons
What was the WHO Analgesic Ladder developed for originally?
Developed for the Tx of CA pain
How do you treat Mild Pain?
W/non-Opioid Analgesics
Name some non-Opioid Analgesics
Acetaminophen
NSAIDS
How do you treat Moderate Pain?
According to WHO Analgesic Ladder
W/Weaker Opioids or Combination Products
How do you treat Severe Pain?
(According to WHO Analgesic Ladder)
What are the 2 most common agents used
in the NICU to tx severe pain?
Stronger Agents
- Morphine
- Fentanyl
In Neonates, Opioids are reserved to treat _____ to _____ pain
Moderate to Severe
What are the Side effects of Opioids (8)?
- Respiratory Depression
- Hypotension
- Glottic and Chest wall rigidity
- Constipation
- Urinary Retention
- Seizures
- Sedation
- Bradycardia
How can Side effects be minimized when prescribing Opioids?
Appropriate Drug Selection
Appropriate Drug Dosing
What should be monitored during Opioid Administration?
Conitnuous Cardiac Monitoring &
Frequent VS
What is Naloxone?
What does it do?
(Narcan)
Competitive Opioid Receptor agonist
Reverses many side-effects of Opioids
In addition to reversal of side effects, what else does Naloxone do?
Antagonizes the Endorphin Effects (Increases pain perception)
Which patients should Not receive Naloxone?
Why?
Infants with Long-term, Chronic exposure of Opioids in Utero
Seizures
What are the long-term side-effects of Naloxone?
We don’t know.
They are not studied.
What is the T 1/2 of Naloxone in a NB?
Why could this be a problem?
~70 minutes
It could be shorter than the T 1/2 of the Opioid
What is the onset of action of Naloxone?
Variable,
IV administration-within minutes
IM administration-within 30 minutes
What might Naloxone be used for?
What is Naloxone NOT used for?
If necessary in the DR, what must be restored 1st?
Narcotic induced Respiratory Depression
In the DR for initial Respiratory Depression
Restore Proper HR and Ventilation
What is the most common Opioid used in NICU?
Morphine
Morphine is soluble in _____ but has poor ______ solubility
Water
Lipid
Morphine metabolites are cleared by the ________ and partly by _____ ________
Kidneys
Biliary Excretion
Is there a difference in Analgestic effect between continuous and intermittent Morphine dosing?
No
What can happen in infants with impaired Renal function receiving Morphine?
Accumulation of Morphine
How is Morphine mainly administered for Analgesia?
IV
Can be used IM (but is painful)
Rectal-exists but wide variability
Morphine clearance improves with?
Postconceptual Age
What 3 signs are A/W the Histamine response from Morphine administration?
Hypotension, Bradycardia, & Flushing
The Histamine response from Morphine is a/w?
Rapid Administration
Morphine may have effects on b/p but are probably dependent on ______ & _______ ___.
Dosing
Gestational Age
What is the Peak of Morphine?
45-90 minutes
What is the Duration of Morphine
4-5 hours
Methadone is a synthetic Opioid with an analgesic potency similar to ______.
Morphine
What medication is Widely used for the tx of Opioid withdrawal in Neonates?
Methadone
Methadone has a Slower/more Rapid distrubution and a more Rapid/Slower elimination than Morphine.
More rapid Distribution
Slower elimination
What medication is used in addicted adults to avoid withdrawl?
Methadone
What medication has a propensity toward muscle rigidity?
Fentanyl
Fentanyl has ___ - ____ fold potency of Morphine
50-100 fold
There is a Narrow/Wide margin of safety with Fentanyl
Wide
What is the onset of Fentanyl?
3-4 minutes
What is the Duration of action of Fentanyl?
30 minutes
Fentanyl is metabolized by _______
Liver
What makes Fentanyl a good choice for precedural pain?
It has a shorter duration (30 minutes)-probably due to increased lipid solubility & molecular confirmation enabling efficient penetration of the BBB
Is the tolerance of a synthetic opioid like Fentanyl faster or slower?
Faster (3-5 days) vs. MsO4 (2 wks) or Heroin (2 wks)
Clearance of Fentanyl may be impaired with what?
Decreased Liver blood flow or function
What agent may be the preferred agent for:
Critically ill pt w/hemodynamic instability;
Symptoms of Histamine release w/Morphine administration; or pts with Morphine tolerance?
Fentanyl
Name the Benzodiazepine most often used in NICU
Midazolam (Versed)
Is a Benzodiazepine an Analgesic?
No
What does a Benzodiazepine do?
Sedation, Anxiolysis, Hypnosis, and Amnesia
Do Benzodiazepines cross the BBB rapidly?
Yes, accounting for rapid onset of action
Can Benzodiazepines cause respiratory depression?
Yes, especially when administered rapidly
Besides respiratory depression, what else can Benzodiazepines cause?
Hypotension
Seizure-like myoclonus (in premature infants w/continuous infusions)
What medication is widely used for management of pain and fever, but lacks anti-inflammatory effects?
Acetaminophen
When is Acetaminophen used?
Mild discomfort
1st immunizations & 24 hours past
NSAID’s have what effects?
Antipyretic, Analgesic, Anti-inflammatory
What side effect do NSAID’s have?
Is it reversible?
Interfere w/Platelet aggregation
Yes, it’s reversible
When can non-pharmacologic interventions be used?
Any time appropriate
What are the non-pharmacologic interventions for pain?
Sucrose NNS Sucrose + NNS KC Facilitated tucking Music Therapy Breastmilk Breastfeeding Multi-sensorial stimulation
