Pain & Analgesic Drugs Flashcards
Neuropathic pain
Pain induced by injury to or disease of the somatosesnory system
-nerve injury or nervous infection
Analgesic
Affects only pain without blocking other symptoms or loss of consciousness
Two types of anesthetic
Local or general
Local anaesthetic
Blocks nerve conduction and all local sensations
-no touch or temperature
General anaesthetic
Loss of sensations and unconsciousness
Anesthetic
Group used for pain
-dulls all sensations as well as pain `
What is important to remember when giving analgesia?
Need to remember what is actually causing the pain
-as the analgesia helps to relieve it
-but isn’t healing the cause
Where do opioids work?
The brain and the spinal cord
Opioids affect what two processes in the brain nad spinal cord
Perception and modulation
In higher centres such as the brain, what do opioids do?
Pain can still be felt but produce less suffering
-perception
In the spinal cord, what do opioids do?
Reduce neurotransmitter release from terminal pain fibres in dorsal horn of spinal cord
-modulation
Opioids bind to
Opioids receptors
Opioids covers any
Drug binding to opioid receptors and can be natural or synthetic
Opiate
Any drug derived from opium
-morphine or codeine
Opium
Juice of the poppy
-palaver somniferum
What two forms of opioids are very similar
Morphine and codeine
What is the difference between morphine and codeine
Codeine has a portion needed to be metabolized before it is the same particle as morphine and can be an analgesic
What’s a better analgesic, morphine or codeine?
Morphine
Properties of different opioids drugs are due to
-affinity and activation for different opooids receptors
-pharmacokinetic differences
All opioids analgesics are ___ ____ or ____ ____ at U and K receptors
Full agonists, partial agonists
Morphine receptors U, Kappa, delta are all
Agonists
U (mu) receptors
Analgesia
-cover a wider variety of brain areas
-can limit the emotional response
K or Kappa receptors
Analgesia
-brain and spinal cord
-can cause dysphoria and hallucinations
Analgesia is in what two receptors
U and K
Opooids can cause sedations and ….
Mental clouding
Delta and mu receptors involve central dopaminergic pathways potentially causing
Euphoria and tranquility
Properties of opoids: antitussive
Depressing cough reflex by acting on a cough centre in medulla
-can be good for a continuous cough
-can be bad if needing to clear lungs
Most dangerous properties of opoids
Depression fo respiratory center
-mu receptors
Opoids can stimulate chemoreceptor and trigger zone of the medulla causing…
Nausea and vomiting
Opioids properties: miosis
Pin point pupil
-excitatory action of parasympathetic nerve inner at in pupil
Risk of continous or first experience on opoids
Tolerance and serious dependence
A very common property of opoids
Constipation
-increase GI muscle tone to point of spasm, increasing tone of anal sphincter