GI+MS: NSAIDs

Question 1

NSAIDS: INDICATIONS

Answer 1

• Mild to moderate pain (eg Dysmenorrhoea, dental pain) => alternative or addition to PARACETAMOL
• Pain related to MS (eg muscle pain, RA, Gout and severe OA)

Question 2

NSAIDS: MOA

Answer 2

• Inhibit PROSTAGLANDIN synthesis from arachadonic acid by inhibiting COX
• COX 1: Stimulate PG synthesis, essential to preserve the integrity of the gastric mucosa, maintain renal perfusion (dilating afferent glomerular arterioles), inhibiting thrombus formation @ the VASCULAR ENDOTHELIUM
• COX 2: Expressed in response to INFLAMMATORY STIMULI, stimulates PGs that cause pain and inflammation
• Benefits primarily via COX 2 inhibition, COX 1 inhibition adv effects
• OVERLAP OF COX INHIBITION

Question 3

NSAIDS: ADVERSE EFFECTS

Answer 3

• GI toxicity
• Renal Impairment
• Increased risk of CV events (eg MI, stroke)
• Adverse effects differ between NSAIDs
• Non selective: Ibuprofen lowest GI risk
• Naproxen and low dose Ibuprofen = lowest CV risk
• COX 2 inhibitors fewer GI side effects, but greater CV risk
• All NSAIDs cause renal impairment
• HSRxns = bronchospasm and angioodema
• Fluid RTN = worsen HTN and Heart Failure

Question 4

NSAIDS: WARNINGS

Answer 4

• Severe renal impairment, NSAID hypersensitivity, heart and liver failure AVOID NSAID use
• PUD/ GI bleeding, CV Dx, Renal Impairment = use safest NSAID @ lowest effective dose in shortest possible time

Question 5

NSAIDS: INTERACTIONS

Answer 5

• MANY DRUGS INCREASE NSAID-RELATED ADVERSE EFFECTS:
• > GI ULCERATION = low dose aspirin, corticosteroids
• > GI BLEEDING = anticoagulants, SSRIs, venlafaxine
• > RENAL IMPAIRMENT = ace inhibitor, diuretics
• > NSAIDs increase the risk of bleeding with WARFARIN

Question 6

NSAIDS: EXAMPLES

Answer 6

• Naproxen = Non selective COX inhibitor
• Ibuprofen = Non selective COX inhibitor
• Etoricoxib = Selective COX 2 inhibitor