NSAIDs( Pharmacology) Flashcards
What are NSAIDs?
Non-steroidal anti-inflammatory drugs
What is inflammation?
The body’s response towards tissue injury that was caused by physical trauma, microbiological agents or noxious chemicals.
What does inflammation assist the body with?
-Remove irritants
-Restore normal structure and function to damaged tissue.
-Inactivate and destroy the invading organisms.
What is the rate limiting step for the formation of arachidonic acid?
Liberation of arachidonate which is catalyzed by phospholipid A2.
What are the functions of prostaglandins?(4)
Formation of blood clots, inflammation, induction of labour and blood flow.
Two major pathways for the synthesis of prostaglandins?(2)
Cyclooxygenase pathway
Lipoxygenase pathway
Three steps of the biosynthesis of prostanoids
- Mobilisation of AA from the membrane phospholipid through the action of phospholipase A2.
- Bio-transformation of AA by cyclooxygenase through a bi-functional action which generates an unstable prostaglandin (PGG2) by cyclooxygenase reaction, and the immediate conversion to PGH2 using the same enzyme by a peroxidase reaction.
- The conversion of PGH2 to specific prostanoids by the action of synthases and specific isomerases.
Another name for cyclooxygenase
Prostaglandin-endoperoxidase synthase
Physiological effects of COX-1 (4)
Maintenance of blood pressure.
Vascular homeostasis
Gastric protection
Platelets aggregation
What induces the COX-2 enzyme?
Inflammatory stimuli
What is the main function of COX-2?
Resp for the production of prostanoid mediators of inflammation.
What role do NSAIDs do? (4)
Reduces pain, prevents fever, prevents blood clotting and decreases inflammation.
Describe the mechanism of action of NSAIDs (3)
•NSAIDs are competitive inhibitors of the active site of COX enzymes (both of them), so they bind and inactivate the enzymes.
• By inactivating the enzymes they inhibit the formation of prastanoids prostaglandin, thromboxane and prostacyclin.
• Thereby preventing inflammation, platelet aggregation, and preventing the pain stimulus from reaching the brain ( no prostaglandins) and is not felt.
Therapeutic effects of NSAIDs (3)
Anti-inflammatory, antipyretic and analgesic effects.
Pharmacological uses of NSAIDs (6)
Headaches, menstrual pain, symptomatic relief, postoperative, chronic joint diseases, acute inflammatory injuries.
Adverse effects of NSAIDs in:
A. GIT (7)
B. Kidneys (2)
C.Skin (1)
D. CNS (3)
E. Haematopoietic effects (3)
A. Abdominal pains, bleeding, anaemia, ulceration, nausea and vomiting , diarrhoea
B. Renal necrosis and haematuria.
C. Stevens johnson syndrome (very rare, fatal)
D. Depression, headache, vertigo
E. Leukopenia, thrombocytopenia, prolonged bleeding due to poor blood clotting.
Examples of non-selective COX inhibitors
Ibuprofen, Aspirin, Neproxen
How is paracetamol different from non-selective COX inhibitors?
Paracetamol only has anti-diuretic and analgesic effects, it has poor anti-inflammatory effects
Examples of COX-1selective inhibitors (3)
Transact, toradol and strepsils
Examples of COX-2 selective inhibitors
Meloxicam, celebrax and arcoxia
Common adverse effects of both the selective inhibitors (3)
Dyspepsia
Diarrhoea
Abdominal pains
An additional therapeutic effect of aspirin
Anti-platelet activity
-inhibits cox1 and prevents formation of thromboxane A2.
- no blood clotting.
Aspirin can be used to prevent which type of cardiovascular disease
Strokes
Which syndrome can be caused by aspirin (most common in children)?
Reye’s syndrome
What are the effects of reye’s syndrome (2)
May result in liver and brain damage.
Symptoms of Reye’s syndrome (5)
Rash, fever, vomiting, convulsions and death.
Why is aspirin not used in pregnant or breastfeeding women
It is teratogenic, it can cross the placenta and it can be present in breastmilk.
