Analgesia Flashcards
Describe the WHO pain ladder for pharmacological management of pain?
Paracetamol, NSAID, weak opioid, strong opioid
Which aspects of the WHO pain ladder can be used in combination in moderate-severe pain?
Paracetamol and NSAID, or paracetamol and weak opioid
Opioid action is mediated by what?
GPCRs
What are the disadvantages of opioids?
Addictive, and numerous side effects
What is the main respiratory side effect of opioids?
Apnoea (respiratory depression)
What is the main cardiovascular side effect of opioids?
Postural hypotension
What are the main GI side effects of opioids?
Nausea and vomiting, constipation
What are some CNS side effects of opioids?
Confusion, euphoria, hallucinations
Opioid agonists produce analgesia mainly through prolonged activation of which type of receptor?
μ (Mu)
Give some examples of opioid agonists?
Morphine, diamorphine (heroin), codeine
Morphine is metabolised by the ? and excreted by the ?
Liver / kidneys
How is codeine always given? What is its main side effect?
Oral / constipation
Give some examples of opioid antagonists?
Naloxone and naltrexone
Opioid antagonists are competitively antagonist to which opioid receptor?
μ (Mu)
When is naloxone used?
To reverse opioid toxicity associated with severe overdose
How is naloxone given?
IV
In opioid addicts, naloxone may trigger what?
An acute withdrawal response
What makes naltrexone different from naloxone?
It can be given orally and has a longer half life
How do NSAIDs work?
They inhibit prostaglandin production by blocking COX1 and COX2
What are some adverse effects of long term NSAID use?
GI damage and nephrotoxicity
Why is paracetamol not an NSAID?
It lacks anti-inflammatory effects and only acts centrally
Gabapentin and pregabalin reduce the surface expression of a particular subunit, and also some of which type of ion channel which are upregulated in damaged sensory neurones?
Ca++
What is a use of gabapentin?
Migraine prophylaxis
What is a use of pregabalin?
Painful diabetic neuropathy
