Pain

Question 1

NSAIDs:
- mech action
- contraind

Answer 1

NSAIDs:
- mech action: analgesic + antiinflammatory + antipyretic actions - cox inhibitor causing decreased prostaglandin inhibition
- contraind: hx PUD, GI bleeding, asthma, renal impairment, dehydrated, hypersens to nsaids/aspirin, no aspirin for children (reyes syndrome where encephalopathy and then fatty infiltration of liver/kidneys/pancreas + hypoglycemia), fluid retention

Question 2

Paracetamol:
- mech action
- se

Answer 2

Paracetamol:
- mech action: inhibits prostaglandin synthesis, analgesic + antipyretic effect
- se: hepatotoxicity in overdosage

Question 3

Opioids:
- mech
- types
- se
- caution
- overdose

Answer 3

Opioids:
- mech: when binding to opioid rec dec GABA release and inc dopamine release causing euphoric effect
- types: morphine, pethidine (10% potency of morphine, has toxic metabolite so not good in renal failure), codeine
- se: n+v, constipation, resp depression, miosis
- caution: liver disease, elderly, asthma
- overdose symptoms + mx: vomiting, hypotension, miosis, resp dep, drowsy. naloxone comp antagonist for rec with high affinity

Question 4

Neuropathic pain
- causes
- mx

Answer 4

• causes: diab neuropathy, post herpetic neuralgia, trigem neur, prolapsed disc
• mx: amitrip/duloxetine/gabapentin/pregabalin. if 1 doesnt work trial another (don’t add on). tramadol for rescue therapy if exacerbation. topical capsaicin for localised e.g. post herpetic
  for elderly trial paracet fiirst

Question 5

WHO ladder

Answer 5

1. nsaids, paracet
2. dihydrocodeine, tramadol, codeine
3. morphine, oxycodone (safe for renal disease!!), methadone, fentanyl, buprenorphine