Flashcards in Analgesia Deck (44)
Drugs that reduce pain at the site of injury do so how?
Decreases sensitisation by blocking's prostaglandin synthesis
Give a example of a drug that reduces pain at the site of injury?
Drugs that reduce nerve conduction of pain do so how?
Block of voltage gates Na+ channels
Give an example of drugs that reduce the nerve conduction to reduce the perception of pain?
List some drugs that reduce the synaptic transmission in the dorsal horn.
List drugs which activate the descending inhibitory controls.
Select tri-cyclic antidepressants
Which drugs target the ion channels that are unregulated in nerve damage?
Antiepileptics e.g. GABA pentinoids
List some common NSAIDs
List some weak opiods
List some strong opiods
In supra spinal antinociception where do the neurones arise from?
Peraqueductal grey mater
Nucleus Raphe Magnus
Where do neurones of the supra spinal anti-nociception project down to?
Posterior horn to the area where the 1st and 2nd order neurones of the spinothalamic tract synapse.
The supra spinal antinociception neurones release what into the synapse?
5 HT (Seretonin)
Noradrenaline and 5 HT have what affect of the spinothalamic tract?
Inhibits the release of Substance P from presynaptic build.
Prevents Depolarisation on the Second order neurone.
What affect does Noradrenaline and 5HT have on the interneurone located by the synaptic cleft of the 1st and 2nd order neurone?
Interneurone is activated and releases Enkephalin (Opiod)
What is the affect of Enkephalin?
Prevents depolarisation of the presynaptic bulb and the sport synaptic neurone.
What kind of receptors do opioids work on?
G protein Coupled Receptors
What is the affect of activating a opioid G protein coupled receptor?
Beta unit - Inhibition of Ca2+ channels suppress excitatory neurotransmitter release.
- opening K+ channels suppressing excitation by hyper-polarising the neurones.
Inhibiting adenyl cyclase - long term suppression
What are the different types of opioid receptors and what are there functions?
μ - most analgesic action and major sideaffects
δ - activation can be proconvulsant
k - Sedation dysphoria and hallucination
List the major respiratory side effects of Opioids.
Apnoea - medullary respiratory system becomes desensitised to CO2 levels
List the major cardiovascular side effects of Opioids
Orthostatic hypotension - reduced sympathetic tone and bradycardia
Histamine mediated dilation
List the major GI side effects of Opioids.
Nausea Vomiting Constipation
-acts on the CTZ
List the major CNS side effects of Opioids.
Confusion Euphoria Dysphoria hallucinations Dizziness Myoclonus Hyperalgesia
Acute and Severe pain
Metaboised in liver
IV IM SC or oral
Severe post operative pain
More lipophilic than morphine
Rapid onset when IV
Mild moderate pain
Anti diarrhoea Antitussive (prevent cough)
75x more potent than morphine
IV to provide analgesia in maintenance anaesthesia
Transdermal or buccal in chronic pain
Acute pain especially labour
Rapid onset IV IM or SC - short duration
Should be given with MAO inhibitors
Useful in chronic pain with patient controlled injection system
Slow onset but long duration of action