Pharmacology; NSAIDs

What are NSAIDs

Are Non steroidal anti inflammatory drugs.

They are called Non steroidal because they reduce inflammation without being steroids like prednisone or Dexamethasone

Precursor for biosynthesis of prostaglandins

Arachidonic acid

Enzyme involved in formation of prostaglandins from Arachidonic acid

Cyclooxygenase

Main prostaglandins

PGE2

PGF2 alpha

PGI2

Another class of substance obtained from Arachidonic acid by the action of lipoxygenase enzyme

Leukotrienes

Features or characteristics of COX1 enzymes

It is constitutive (It is always present and is continuously expressed)

It’s widely distributed. Present in most tissues under normal conditions

It participates in various physiological functions such as protection of gastric mucosa, homeostasis and regulation of cell division

Produces prostaglandins that maintain normal body functions

Features or characteristics of COX2 enzymes

Is inducible. COX2 is not always present, it is induced during inflammation (by cytokines and endotoxins), infection and tissue injury

Produced prostaglandins that causes pain(sensitive nerve endings), fever(acts on hypothalamus) and inflammation(vasodilation and swelling)

Tissue distribution. Law or absent in most normal tissues

Mainly pro inflammatory prostaglandins

Uses of PGE2

Reduce acid secretion and increase the secretion of mucus in the stomach (cytoprotective action), GIT

Cause vasodilation (cardiovascular system)

In low concentration, can contact pregnant uterus, mainly used in mid trimester abortion , missed abortion and in hydratidiform mole (uterus)

Induction of labor (uterus) Cervical priming

PGE1 (alprostadil) is used in treatment of erectile dysfunction

Uses of PGI2 (prostacyclin)

Reduce acid secretion and increase secretion of mucus on the stomach (GIT)

Cause vasodilation (cardiovascular system)

Decreases peripheral, pulmonary and coronary resistance (cardiovascular state)

PGI2 (epoprosterol) is used to treat pulmonary hypertension. Other analogies used in this condition are; treprostinil and illoprustjj (cardiovascular)

Inhibits platelet aggregation hence useful during hemodialysis to prevent platelet aggregation (platelets)

PGF2 alpha

Constricts pulmonary veins and arteries

Decreases intraocular tension. Its analogues e.g latanoprost, bimatoprost,travoprost and unprostone are used in glaucoma (Eye)

Contracts pregnant uterus. Mainly used in mid trimester abortion, missed abortion

Induction of labor ( uterus)

Cervical priming

Post parting hemorrhage , Carboprost can be used

PGD2

Cause vasodilation

Thromboxane A2

Is a vasoconstrictor

PGE2 analogue

Dinoprostone

Dinopostone uses

Exists as vaginal tab and vaginal gel

Induction of labor

Mid term abortion

Termination of pregnancy

PGF2 alpha analogues

Dinoprost

Carboprost (15-methyl PGF2 alpha)

Dinoprost

Is a PGF2 alpha analogue

Uses of Dinoprost

Given by intra-amniotic injection

Mid term abortion

Uses of Carboprost

Intramuscular injection

Mid term abortion

Control of PPH

PGE1 analogues

Gemeprost

Alprostadil

Misoprostol

Gemeprost

Given as vaginal pessary

Cervical priming in early prgnancy

Alprostadil uses

Can be given as intravenous infusion and

Classification of NSAIDS

Non selective COX inhibitors

Preferential COX 2 inhibitors

Selective COX 2 inhibitors

Non selective cox inhibitors

Salicylates

Fenamic acid derivatives

Acetic acid derivatives

Enolic acid derivatives