NSAIDs Flashcards
What is pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
What is allodynia?
pain due to stimulus which does not normally provoke pain
What is hyperalgesia?
- increased response to stimulus which is normally painful
What are the types of chronic pain? (and examples)
- nociceptive = receptors from site of injury to CNS (OA and RA)
- neuropathic = initiated by primary lesion or dysfunction in nervous system (central or peripheral)
- visceral = involves internal organs (IBS)
- mixed pain = various origins (lower back, fibromyalgia)
What is somatic pain?
- aching, often constant
- dull or sharp
- worse with movement
- localised except when deep (muscle, tendon, ligament, bone, fascia and joints)
- OA pain
- Hilton’s Law
What is the WHO analgesic ladder?
1) NSAIDs, non-opoid analgesics
2) + weak opoids
3) + strong opoids (methadone), oral admin., transdermal patch
4) + nerve block, epidurals, neurolytic block therapy, spinal stimulation
(may start higher up or from top then go down with acute pain, up ladder with chronic pain)
What are NSAIDs used for?
- analgesic for inflammation
ibuprofen, aspirin, COX2 inhibitors, diclofenac plus many others
What is the mechanism of action of aspirin?
- COX1 and COX2 inhibitor
- analgesic, antipyretic and anti-inflammatory
What is the mechanism of action of ibuprofen, diclofenac and ketoprofen?
- COX1 and COX2 inhibition
- analgesic and anti-inflammatory
What are the selective COX2 inhibitors?
rofecoxib, celecoxib, etroicoxib and meloxicam
What happens if COX is inhibited in the stomach?
- decreased mucus secretion
- decreased bicarbonate secretion
- decreased blood flow
How is there an increased CV risk with COX1 inhibitors?
- related to strokes
- COX1 inhibition = increased vasoconstriction = aggregation of platelets
- rofecoxib, diclofenac, ibuprofen and celecoxib
What is the COX3 controversy?
- transcribed from COX-1 gene
- hypothesised as target for paracetamol
- appears non-functional in humans
What is the mechanism of action of paracetamol?
- does not inhibit COX outside of CNS
- modulates cannabinoid system
- activates serotonergic descending pathways
What is the difference between acute and chronic pain?
Chronic lasts longer than 12 weeks/3 months
Acute is a response to injury/post operative flare, diminishes with tissue healing