NSAIDs

Question 1

Describe the MA of NSAIDs?

Answer 1

NSAID: non-selective COX inhibitor -> reduced formation of prostaglandins, thromboxanes and prostacyclin

o Inhibition of COX2 (inducible): anti-inflammatory, analgesia, antipyretic
o Inhibition of COX1 (constitutive):
- inhibition of PGs for GIT mucosa (maintain mucosal blood flow, hydrophobic surface layer, bicarb secretion)
- platelet aggregation (thromboxanes)
- dilation of afferent arteriole (GFR reduction when inhibited)
o Increased arachadonic acid breakdown by 5-lipoxygenase (as not broken down by COX) -> increased leukotriene production
-> increased vascular permeability and construction of bronchial smooth m

Question 2

List some examples of NSAIDs?

Answer 2

Aspirin, ibuprofen, naproxen, diclofenac

Question 3

List some SE of NSAIDs?

Answer 3

o GIT: dyspepsia, PUD, GI bleed, gastritis
o Renal: acute renal failure (afferent vasoconstriction), electrolyte and fluid abnormalities (hyperkalaemia, hyponatraemia, oedema)
o CVS: bleeding, MI, stroke (reduced prostacyclin- needed for endothelium, SM relaxation, vasodilation)
o Resp: bronchospasm
o Haem: reduced platelet aggregation
o Anaphylaxis
o Skin- rash (Steven Johnson syndrome)
o Hepatotoxicity (rare)

Question 4

List some CI of NSAIDs?

Answer 4

• known hypersensitivity
• asthma sensitive to NSAIDs
• active bleed
• pregnancy 3rd trimester (premature PDA closure, miscarriage)