Pain Management Flashcards
define somatic pain
localized aching or throbbing
define visceral pain
pain in organs
define central pain
non-nerve related, pain that cannot be identified physically
fibromyalgia is categorized under what type of pain?
central pain
what is the purpose of the JCAHO accreditation?
inform patients rights to pain assessment and management
define nociception
sensation of pain
define proprioception
perception of the body/placement of limbs
define allodynia or hyperalgesia
hypersensitivity and pain response to normal tactile stimuli. such as a sunburn
define analgesia
blocking only of nociception
define anesthesia
blocking all sensation
where does initiation of pain occur?
from stimulus in periphery
where does transmission of pain occur?
in spinal cord
where does perception of pain occur?
in brain
where does reaction of pain occur?
what is the reaction?
in brainstem-reflex motor
inhibition or sensitization outputs
what do Mu opioid receptors do on pre-synaptic neuron?
blunt pain and block calcium channels to decrease NT release
Mu opioid receptors are inhibitory or non-inhibitory?
G-protein coupled or non-G protein coupled
inhibitory and G-protein couplred
what do the free nerve endings in the dermis of skin sense?
light touch, pressure, or pain perception
where is the first stop once a pain signal is initiated?
the spinal cord dorsal horn
what do Mu opioid receptors do on post-synaptic neuron?
cause hyperpolarization by increasing k+ out of neuron and desensitize
what part of the brain is the primary site for distribution of pain signals?
thalamus
projections to _____________ localize pain
somatosensory cortex
projections to ________ and _______ shape emotional and cognitive responses and reactions
prefrontal cortex, limbic areas
which parts of the brain carry out descending modulation of pain?
rostral ventromedial medulla
periaqueductal gray
which parts of the brain influence motivational information (to prevent future pain)?
Ventral tegmental area
Thalamus
which parts of the brain process your emotional response to pain?
Anterior cingulate cortex
Insula
Nucleus accumbens
Amygdala
Parabrachial nucleus
how do opioids interact with GABA?
they inhibit GABA inhibition of descending inhibitory pathways
Explanation: they block the inhibition caused by GABA in descending inhibitory pathways to allow activation of the descending inhibitory pathways to block pain
which two NTs do descending inhibitory pathways utilize to activate inhibitory interneurons in the dorsal horn?
Given what these two NTs are, what drug class has analgesic action?
5-HT and NE
SNRIs
what are the 3 sites of opioid action? (PAG, RVM, and DH)
periaqueductal gray, rostral ventromedial medulla, and dorsal horn
define a narcotic
anything that dulls the senses, relieves pain and induces sleep
define opioid
anything that binds to opioid receptors
preproopiomelanocortin, preproenkephalin, prepordynorphin, and preproorphanin are all classified as?
opioid receptor agonists
Beta-Endorphin, Met-enkephalin, and Leu-enkephalin all have high affinity for which types of opioid receptors?
mu and delta
dynorphin A and B have high affinity for which opioid receptor type?
kappa
what effects would you expect from drugs that target mu opioid receptors?
analgesia, sedation, euphoria, respiratory depression, constipation and dependence
what effects would you expect from drugs that target delta opioid receptors?
mild analgesia, less respiratory depression, less constipation (compared to mu)
what effects would you expect from drugs that target kappa opioid receptors?
analgesia, less respiratory depression, dysphoria, less dependence, minimal constipation (compared to mu)
how does respiratory depression occur when using CNS depressants?
The pons region of the brain has decreased sensitivity to pCO2 and therefore you don’t realize you need more oxygen in the brain
how do opioids have antitussive effects?
inhibits cough center in the medulla
why do opioids cause nausea and vomiting?
they stimulate the chemoreceptor trigger zone
opioids cause miosis or mitosis?
miosis
T/F opioids block the baroreflex
false, they blunt it, not completely block
opioid effect on stomach:
decreased secretions and motility
opioid effect on intestines:
decrease propulsion and water secretion
opioid effect on sphincters:
contraction of smooth muscle
what is the mechanism behind opioids decreasing stomach secretion/water secretion?
they decrease cAMP levels which are important for water secretion which is important for gut mobility
what is the mechanism behind opioids causing sphincter smooth muscle contraction?
decreasing cAMP levels causes contraction of smooth muscle
opioid effect on urinary tract:
contraction of smooth muscle - urinary retention
opioid effect on uterine smooth muscle:
prolongation of labor
opioid effect on bronchiole smooth muscle:
constriction, may be problematic in asthma
opioid effect on vascular smooth muscle:
hypotension from release of histamine
opioid effect on basal metabolic rate and temperature:
modest decrease
opioid effect on immune system:
modest immunosuppression
opioid effect on mast cells:
histamine release
opioid effect on pituitary:
possible increase in prolactin and growth hormone
opioids can cause hypogonadism which is a decrease in hormones such as estradiol and testosterone. what SEs would you expect?
decreased libido, menstrual irregularity
what are the diagnostic triad signs of acute overdose of opioids?
pinpoint pupils, respiratory depression, and coma
what is the indication of opioid-induced hyperalgesia?
increasing dose without relief
You can build tolerance to opioid SEs except for which two SEs?
constipation and miosis
why can NSAIDs, SNRIs, acetaminophen, local anesthetics, and alpha 2 agonists be helpful as combo therapy with opioids?
they reduce pain at lower opioid doses so you can dose less opioid
list all of the withdrawal symptoms from opioids:
(T T S H P P I M D L N V H I)
tachypnea (rapid breathing)
tachycardia
sweating
hypertension
piloerection
pupillary dilation and photophobia
insomnia
myalgia
diarrhea
lacrimation
nausea
vomiting
hyperthermia
irratability
what drug can be used to treat the autonomic hyperactivity and anxiety from opioid withdrawal?
clonidine
what drugs can be used to treat myalgia from opioid withdrawal?
NSAIDs
what drug can be used to treat diarrhea from opioid withdrawal?
loperamide
what is the longest acting opioid agonist? what is it used for?
methadone: pain management of opioid use disorder as maintenance therapy
what drug has a toxic metabolite and should be avoided?
meperidine
codeine must be metabolized to ____ for efficacy, many people are _____ metabolizers
morphine, poor
TRV130 has biased agonism, explain what this means
mu opioid receptors have two components - G protein and Beta-arrestin. G protein is normally blocked by Beta-arrestin which decreases respiration and GI function. TRV130 blocks Beta-arrestin, allowing G protein to stay active which will increase analgesic effects
what drug formulations does Naloxone come in?
IM, IV, or nasal
what is Naltrexone used for?
to treat opioid use disorder and alcoholism
How do Naloxegol, Methylnatrexone, Naldemedine, and Alvimopan work for treating opioid-induced constipation?
they are opioid antagonists that have no CNS effects, so they can block opioid stimulation in periphery w/o blocking pain relief
why would we prescribe oxycodone + naloxone, buprenorphine + naloxone, or pentazoxine + naloxone?
they prevent people from IV injecting opioids => naloxone blocks opioid actions if injected, but not if taken orally, so patient has to take med orally to have any pain relief
