Pain Flashcards
What are the different types of pain?
Nociceptive (somatic or visceral)
Neuropathic (central or peripheral)
What is postherpetic neuralgia
Residual pain after shingles, occurs where the raw used to be
What is fibromyalgia?
Symptoms encompassing pain, tiredness, mood problems
What is trigeminal neuralgia?
Nerve pain in the face
What are the 3 steps on the WHO analgesic ladder?
Pain score 2-5/10: non-opioids
Pain score 5-8/10: mild opioids
Pain score 8+/10: strong opioids
Step 1 opioid pain ladder
Paracetamol 1-4g daily is good basis
Analgesic, antipyretic, not anti inflammatory
NSAIDs inhibit COX so are also anti inflammatory
COX2 effect for pain relief and anti-inflammatory
COX1 causes side effects
Side effects of NDAIDs
Dyspepsia Nausea Gastric irritation Fluid retention Renal impairment Brinchospasm
Drawbacks of COX-2 specific NSAIDs
Increased risk of CV effects
Led to withdrawal of Rofecoxib
Avoid coxib use in ischaemic heart disease or risk thereof
Non-selective Diclofenac also lost P status due to risk
Step 2 codeine considerations
10% of population cannot convert to morphine
Variations in CTP2D6 metaboliser status
Risk of overdose for breastfed infant
Step 2 - Tramadol
Opioid analgesic and SNRI dual action giving synergistic effect
May lower seizure threshold so avoid in epilepsy
Difficult to stop taking due to serious withdrawal effects
Step 3 morphine respiratory depression risk?
Pain is antagonist to central depressant effects, so this is not a concern in cancer pain
But morphine may accumulate in renal impairment
Methadone
Strong opioid
Long (18hr) half life so once daily dosing
Allodynia
Pain caused by stimulus that would not normally cause pain
I.e. a lowering of the pain threshold
Hyperalgesia
Severe pain from stimulus that would normally only cause a slight pain
Ie heightening is the pain response
Paraesthesia
Pain without a stimulus eg pins and needles, electric shock sensation
