Question

How do anti-inflammatory steroids and NSAIDS differ in their effects on eicosanoid synthesis? Please Check and Add to my Answer?

This is a question from a study guide for my first A&P exam. So far, this is what I have come up with, but it does not explain anti-inflammatory steroids?

NSAIDS are used for inhibition of:
- pain receptors
- fever
- inflammation
NSAIDS block formation of prostaglandins (aka eicosanoids) through (COX) enzyme inhibition.

Answer 1

Steroids blocks inflammation mostly by the following mechanisms:

1 . In the macrophages,monocytes and endothelium steroids induce the production of lipocortin,which inhibits phospholipase `A_2`,this enzyme is responsible for production of arachidonic acid,which is a precursor of prostaglandins,leukotrienes etc.(mediators of inflammation)

2 . They also block production and release of different cytokines(Interleukins and TNF),which act as mediators of inflammation.

3 . At the genetic level they causes transrepression of proinflammatory transcription factor (NF - k`beta`)

4 . They also decreases the Ig E dependent release of histamine and decreases production of Acute Phase Reactants.

On the other hand, NSAIDs(Non Steroidal Anti Inflammatory Drugs) acts mainly via following mechanisms,

1 . They either non selectively (e.g : Aspirin,Ibuprofen,Diclofenac) or selectively(e.g: celecoxib,Parecoxib,Paracetamol) block the enzyme Cyclooxygenase 1,2,3(3 for paracetamol only)(COX),which produces prostaglandins from arachidonic acid)

2 . They also inhibit ICAM,VCAM which are mediators of inflammation.

3 . They prevent generation of superoxide radical as well.

As a result, NSAIDs can be used for Antipyretic,Antiinflammatory,Analgesic and Antiplatelate action(blood thinning agent)

In short, Steroids block arachidonic acid production,whereas NSAIDs block the next step of production of mediators of inflammation from arachidonic acid..