NSAID's Flashcards
What does the term NSAIDS refer to?
Non-steroidal anti-inflammatory drugs. Used to: 1) Reduce pain. 2) Lower body temperature in a person with a fever. 3) Decrease inflammation
What is the relationship between the enzymes ‘cyclo-oxygenase’ and ‘lipo-oxygenase’?
Cyclo-oxygenase facilitates the process by which arachidonic acid forms prostaglandins, prostacyclin and thromboxane A2.
Lipo-oxygenase facilitates the process by which arachidonic acid forms leukotrienes.
Name the enzyme required to convert phospholipids to arachidonic acid.
Phospholipase A2
Explain the function of the inflammatory process.
Inflammation is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair.
What is the role of prostaglandins in the inflammatory response?
PG increase vascular permeability, pain and fever. PG are powerful locally acting vasodilators and inhibit the aggregation of blood platelets and therefore blood clots.
At what stage of the inflammatory process do NSAIDS exert their action?
NSAIDs block the COX enzymes and reduce production of prostaglandins. Therefore, inflammation, pain, and fever are reduced by all COX inhibitors.
Why don’t NSAIDS completely eradicate the inflammatory process?
Other inflammatory mediators which are not related to cox are still present e.g. leukotrienes.
If the inflammatory process is so beneficial for our survival, why do we even need anti- inflammatory drugs?
Associated swelling can be associated with morbidity and mortality
Apart from NSAID’s, which is the other group of drugs frequently prescribed as anti- inflammatories?
Steroids.
Name the 2 main sub-groups of NSAID’s. Describe in one sentence the fundamental difference between these 2 types, in terms of its mechanism of action.
1st generation and 2nd generation.
1st generation inhibits both cox 1 and cox 2. 2nd generation inhibits only cox 2.
What does COX stand for? What are the differences between COX-1 and COX-2?
Cyclo-oxygenase
Cox 1 works on arachidonic acid that has been produced from a Physiological Stimulus,
Cox 2 works on arachidonic acid that has been produced from an Inflammatory Stimulus and has no affect on stomach and platelets (unlike cox1).
Examples of 1st generation NSAID’s.
Paracetamol, Diclofenac, Indomethacin, Piroxicam, Mefanamic acid, Aspirin, Ibuprofen and Naproxen.
Examples of 2nd generation NSAID’s.
Nimesulide, Rofecoxib, Celecoxib.
Where are NSAIDS absorbed from when taken orally?
Small intestine.
What other routes of administration are there?
Rectal and topical.
Where are NSAID’s metabolised?
Liver.
Where are they excreted from?
Kidney.
Explain the mechanism by which NSAID’s exert their analgesic action?
1) Central analgesic effect in spinal cord.
2) Peripheral effect - desensitisation of afferent nerves (those nerves which carry information to the brain).
Explain the mechanism by which NSAID’s exert their antipyretic action?
Inhibition of PG synthesis in the hypothalamus.
Explain the mechanism by which NSAID’s exert their anti-inflammatory action?
Reduction of PG synthesis at site of
injury.
Explain the mechanism by which NSAID’s can cause abnormal bleeding?
NSAIDs block the COX enzymes and reduce production of prostaglandins. Therefore, inflammation, pain, and fever are reduced by all COX inhibitors. Since the prostaglandins that protect the stomach and promote blood clotting also are reduced, NSAIDs can increase the risk of bleeding. So they inhibit platelet function.
Explain the mechanism by which NSAID’s can cause gastrointestinal symptoms?
Inhibit the PG which normally protect
the gastric mucosa.
Explain the mechanism by which NSAID’s cause problems in individuals with compromised cardiovascular function?
Increased risk of myocardial infarction with many (not asprin), probably due to effect on prostacyclin (prostacyclin is a vasodilator and inhibits platelet aggregation).
Explain the mechanism by which NSAID’s damage the kidney?
Renal PG dilate afferent arterioles, thus maintain glomerular filtration. if these are inhibited, renal flow is affected.
Also, NSAID’s can cause two different forms of acute kidney injury. 1) Acute tubular necrosis. 2) Acute interstitial nephritis.
What are the effects of NSAIDS in a pregnant woman?
NSAID’s may delay labour.
What types of individuals need to take particular care when using NSAIDS?
Individuals with bleeding tendencies, gastric diseases (or history of), renal dysfunction, hypersensitvity reactions, elderly, CVS dysfunction.
Match the generic drug name with the appropriate trade name.
GENERIC NAME / TRADE NAME Paracetamol / Panadol, Panama. Indomethacin / Indocin Aspirin / Disprin, Cardiprin Naproxen / Naprosyn Mefanamic acid / Ponstan Ibuprofen / Nurofen, Brufen Piroxicam / Feldene Celecoxib / Celebrex Diclofenac / Voltaren
Why should children and adolescents with an ‘influenza-like’ illness NOT be given aspirin?
Reye syndrome.
What would be the possible result of an individual overdosing on aspirin or paracetamol?
Asprin: fluid, electrolyte and acid-base imbalance (mixed respiratory alkalosis and a metabolic acidosis.) hepatic and nephrotoxicity.
Paracetamol: liver damage.
