Opiate Analgesics Flashcards
What kind of disease is delayed by analgesics?
RA
What are the four types of analgesics?
- opioids
- NSAIDs
- Glucocorticoids
- DMARDS
Where do analgesics work?
Dorsal horn afferent neurons synapse
At site of pain/inflammation
Promoting pain repression signal
What is the prototypical opioid analgesic?
Morphine
What are opioids used for, besides analgesia?
Euphoria
Relief from diarrhea
Cough suppression
What is opium?
Greek word meaning “juice” from the poppy seed
What is opiate?
Drug extracted from the exudate of the poppy
What is an opioid?
Natural or synthetic drugs that binds to the opioid receptors producing an agonist effect
What is a narcotic?
Term used to characterize pharmacological compounds used to treat moderate to severe pain
What is narcosis?
Stuporous or somnolent state
What are the two naturally occurring opioids?
Morphine and codeine
How does the potency or codeine compare to morphine?
6-7x less
How does the potency of morphine compare to heroin?
Heroin is 2x more potent than morphine
What are the endogenous opioids?
Endorphins
Enkephalins
Dynorphins
What are the two major endogenous opioid receptors?
Mu1
Mu2
Where are Mu1 opioid receptors located? What is their purpose?
Outside the spinal cord
Responsible for central interpretation of pain
Where are Mu2 receptors located? What is their purpose?
Located throughout the CNS
Responsible for supraspinal and spinal analgesia
What are kappa opioid receptors?
Modest supraspinal and spinal analgesia
What are delta opioid receptors?
Modest supraspinal and spinal analgesia
How well are opioids absorbed from the GI tract?
Well, but high first pass effect
What is the primary hepatic metabolism of morphine?
glucuronidation– morphine-6-glucuronide
What does the liver metabolize heroin and codeine to?
Morphine
What is the G protein that opioid receptors act on? What does this do?
Gi/G0 coupling, causing inhibition of adenylate cyclase, and decreased cAMP production
What is the MOA of opioids? (2)
Gi/Go excitation, causing:
- a loss of intracellular Ca and decrease release of neurotransmitters
- Increase postsynaptic opening of K channels, resulting in hyperpolarization
Where do opioid receptors work?
Inhibition of the afferent pain transmission
What are the peripheral effects of opioid receptors?
Activation of distal ends of primary afferent neurons decreases their activation and excitability
What are the effect of opioids on the dorsal horn of the spinal cord?
Presynaptic: block release of pain modulating neurotransmiting
Postsynaptic: opioids inhibits secondary afferent neurons via increase K channel conductance
What is the role of opioids in the descending pain pathways?
Block the inhibitory GABAergic interneurons, leading to enhance inhibition of nociception
What are the three sites of opioid action on the descending pain pathway?
Periaqueductal gray
Rostral ventral medulla
Locus coeruleus
Opioids provide analgesia in two general ways. What are they?
Reduce sensation and affective aspects of pain
In whom is sedation d/t opioids more frequent?
older folks
What is the COD for opioid OD?
Inhibition of the brainstem respiratory mechanism
What happens when there is a buildup of pCO2 d/t decreased respiration secondary to opioid use?
Reflexive cerebral vasodilation
What are the eye findings of opioid use?
Constriction of pupils
How do opioids reduce cough?
Suppress the cough center of the brain via brain stem chemoreceptor trigger zone
Stimulants cause what eye findings?
Mydriasis