NSAIDS Flashcards
what is the pharm class of Aspirin?
NSAID
How does Aspirin help with pain?
- When there is an injury, the pain site releases PGI2, bradykinin, leukotrienes, By blocking the PGI2, it sensitises the nociceptive fibres to other stimulating factors.
What is analgesic ceiling?
there is a limit to its effectiveness as aspirin only blocks the sensitisation, it activate the nociceptive fibres.
what does PGI2 and PGE2 do when there is pain?
vasodilation, increases vascular permeability, pain.
What does aspirin help with (anti-?)
antipyretic, antiplatelet
how does aspirin act as an antiplatelet?
it blocks the
1) thromboxane TXA2 which helps with platelet aggregation.
- takes 1-2 weeks to restore with new platelets.
2) PGI2, also platelet aggregation. takes 3-4 hours to restore it with new COX synthesis
Is aspirin a reversible or irreversible COX inhibitor?
irreversible.
How does aspirin help with fever?
when there is inflammation, neutrophils are released, cytokines, COX enters blood brain barrier to hypothalamus- body core temp, reset body temp.
Does NSAID alter the body temperature?
No.
Are children allowed to consume aspirin?
No, it causes Reye’s syndome. Children with viral infections are at higher risk.
What is reye’s syndome and its signs and symptoms?
swelling of the brain ( encephalitis) and liver swelling,
- vomit
- personality changes
- listlessness
- LOC
-delirium
-convulsions
what are examples of other NSAIDs
naproxen, indometacin, diclofenac
What are the characteristics for naproxen? eg, half life
- more effective in women
- used for dysmenorrhea
-half life is 12-24 hours, BD dose is sufficient
what are the characteristics of indometacin
- strong anti inflammatory drug with steroid like phospholipase A
- 15-25% reported CNS adverse effects eg. depression, psychosis, hallucination, confusion.
what are the characteristics of diclofenac?
half life- 2 hours, reduces GI risk.
- longer half life in synovial fluid in joints- great for inflammatory joint pain.
- exists in cream form too.
what are the adverse effects of NSAIDs? aspirin
1) reye’s syndrome.
2) GI: dyspepsia, n/v, ulcer, haemorrhage.
- blocks prostaglandin: increases mucus secretion, lowers gastric acid secretion, increases bicarb secretion, mucosal blood flow.
3) renal: blocks PGI2, PGE2.
PGI2: 1) hyper k
2) AKI
3) suppression of renin- aldosterone secretion.
PGE2: retain water and sodium- oedema, HTN.
4) pseudo allergic like reaction: rash, nasal congestion, anaphylactic shock.
5) asthma due to overproduction of leukotrienes.
when should you use NSAIDs with caution?
urticaria
asthma
nasal polyps
what are the risk factors of NSAID induced AKI?
1) old age above 65 years old, has htn and atherosclerosis.
- narrowing of renal arterioles may reduce the capacity of renal afferent dilatation.
2) pre-existing glomerular/renal disease - renal afferent dilatation needed to maintain GFR
3) volume depletion-
- reduces renal glomerular afferent arteriolar pressure and activates angiotensin 2.
4) ACE-i, ARB, Diuretics/ triple whammy.
- prevent efferent arteriolar vasoconstriction- required to maintain GFR.
which type of NSAID causes greater risk of GI side effects? COX-1, COX2?
COX-1
what class is etoricoxib?
COX-2inhibitor
where is COX -2 found in?
CNS, kidneys, reproductive organs, synovial fluid.
What is COX-2 good for?
it has lesser side effects compared to COX -1
What are the adverse effects of Etoricoxib?
1) renal toxicity
2) Affects ovulation- delayed follicular release
3) Premature closure of ductus arteriosus in fetal
4) Impaired wound healing- #, PUD
5) Increases risk for thrombosis, increases TXA2, platelet aggregation.
What are the contraindications of Etoricoxib? 7
1)Severe renal failure
2) Heart failure
3) GI bleed
4) Bleeding disorders
5) 3rd trimester in pregnancy ( ALL NSAIDs)
6) systemic corticosteroids, antiplatelets, anticoagulant
7) multiple risk factors for NSAIDs toxicity
