Pharma
June 19, 2023
What is analgesics??
Pain:
An unpleasant sensory and emotional experience associated with potential or
actual tissue damage.
A personal and individual experience
Whatever the patient says it is
Exists when the patient says it exists
Nociception
Pain that results from stimulation of sensory nerve fibres called nociceptors
These receptors transmit pain signals from various body regions to the spinal cord
and brain.
Nociceptors will be activated
Increase in glutamate release = nociceptor (free nerve endings) gets activate =
creates an action potential = influx of ions = afferent sensory neuro = dorsal root
ganglion (neurons cluster together) = dorsal root of spinal cord =
Spinothalamic tract = ascending neural pathway
Nociceptors = dorsal root ganglion = dorsal horn of spinal cord = synapse = second
order neuron = moves (neuron decussate) to ipsilateral side of spinal cord
(third order neuron) Relay station (thalamus) = takes info from peripheral nervous
system and decides where the signal goes.
Post central - somatosensory cortex = create action plan =
Reflex arch
A delta (fast, myelinated), small diameter and C fibers (unmyelinated)
What opioids do? Block action potential – not perceived as pain.
Found in membranes in afferent neuron : opioid receptors = found in dorsal horn
of spinal cord
Delta
MU – potent in dorsal horn spinal cord – increase sensitivity to pain.
Kappa
, Agonist – chemical synthetic opioid
Pain threshold
Level of stimulus needed to produce the perception of pain
A measure of the physiological response of the nervous system
Pain tolerance
The amount of pain a person can endure without it interfering with normal
functioning
Varies from person to person
Subjective response to pain, not a physiological function
Varies by attitude, personality, environment, culture, ethnicity
Polymorphism – different pain perceptions with individuals – decrease threshold
from pain.
Classification of pain by onset and duration
Acute pain
Sudden onset
Limited has an end
Persistent pain (chronic pain)
Persistent or recurring
Lasts 3 – 6 mos
More difficult to treat
Tolerance – not as sensitive overtime, more medication to achieve
therapeutic effect.
Classification of pain
Referred pain
Neuropathic - electric
Phantom – pain in amputated part of body – CNS gets confused
Cancer – main complaint with people with CA, CA-related fatigue
Central – thorax, torso
Vascular – angina, ischemic type pain, no adequate blood flow (DVT)
Gate theory of pain transmission
Most common and well-described theory
Uses the analogy of a gate to describe how impulses from damaged tissues are
sensed in the brain
Many. Current pain management strategies are aimed at altering this system.
June 19, 2023
What is analgesics??
Pain:
An unpleasant sensory and emotional experience associated with potential or
actual tissue damage.
A personal and individual experience
Whatever the patient says it is
Exists when the patient says it exists
Nociception
Pain that results from stimulation of sensory nerve fibres called nociceptors
These receptors transmit pain signals from various body regions to the spinal cord
and brain.
Nociceptors will be activated
Increase in glutamate release = nociceptor (free nerve endings) gets activate =
creates an action potential = influx of ions = afferent sensory neuro = dorsal root
ganglion (neurons cluster together) = dorsal root of spinal cord =
Spinothalamic tract = ascending neural pathway
Nociceptors = dorsal root ganglion = dorsal horn of spinal cord = synapse = second
order neuron = moves (neuron decussate) to ipsilateral side of spinal cord
(third order neuron) Relay station (thalamus) = takes info from peripheral nervous
system and decides where the signal goes.
Post central - somatosensory cortex = create action plan =
Reflex arch
A delta (fast, myelinated), small diameter and C fibers (unmyelinated)
What opioids do? Block action potential – not perceived as pain.
Found in membranes in afferent neuron : opioid receptors = found in dorsal horn
of spinal cord
Delta
MU – potent in dorsal horn spinal cord – increase sensitivity to pain.
Kappa
, Agonist – chemical synthetic opioid
Pain threshold
Level of stimulus needed to produce the perception of pain
A measure of the physiological response of the nervous system
Pain tolerance
The amount of pain a person can endure without it interfering with normal
functioning
Varies from person to person
Subjective response to pain, not a physiological function
Varies by attitude, personality, environment, culture, ethnicity
Polymorphism – different pain perceptions with individuals – decrease threshold
from pain.
Classification of pain by onset and duration
Acute pain
Sudden onset
Limited has an end
Persistent pain (chronic pain)
Persistent or recurring
Lasts 3 – 6 mos
More difficult to treat
Tolerance – not as sensitive overtime, more medication to achieve
therapeutic effect.
Classification of pain
Referred pain
Neuropathic - electric
Phantom – pain in amputated part of body – CNS gets confused
Cancer – main complaint with people with CA, CA-related fatigue
Central – thorax, torso
Vascular – angina, ischemic type pain, no adequate blood flow (DVT)
Gate theory of pain transmission
Most common and well-described theory
Uses the analogy of a gate to describe how impulses from damaged tissues are
sensed in the brain
Many. Current pain management strategies are aimed at altering this system.
