Flashcards in NSAIDs Deck (34)
What are the three major uses of NSAIDs?
What are most deaths due to NSAIDs caused by?
Broadly speaking, how do NSAIDs act?
They inhibit the production of prostanoids by COX enzymes
What are the main prostanoids?
Prostaglandins (D2, E2 and F2) Prostacyclin (PGI2) Thromboxane A2
What does COX convert arachidonic acid to?
Which is then converted by specific synthases to:
Prostaglandin D2, E2, F2
How are prostanoid receptors named?
Prostanoid receptors aren’t very specific - they are named based on which prostanoid they have the highest affinity for
What type of receptor are all the prostanoid receptors?
G protein coupled receptors (though not all their actions are G protein mediated)
State some unwanted actions of PGE2.
Increased pain perception
Acute inflammatory response
Inhibition of apoptosis
How does PGE2 affect body temperature?
PGE2 stimulates hypothalamic neurones initiating a rise in body temperature
Which prostanoid receptor is responsible for signalling in acuteinflammation?
EP3 (on mast cells)
Which prostanoid receptor is responsible for the effects of PGE2 on the immune system?
Which diseases are treated with NSAIDs due to its effects on the immune system?
Multiple Sclerosis and Rheumatoid Arthritis (Th17 involvement)
Contact Dermatitis (Th1 cells involved)
What is the problem with PGE2 inhibiting apoptosis?
Inhibition of apoptosis increases the likelihood of necrosis
State some desirable actions of PGE2 and other prostanoids.
Regulation of renal blood flow
Describe the gastroprotective action of PGE2.
PGE2 downregulates stomach acid production
PGE2 stimulates mucus production
PGE2 stimulates bicarbonate production
What effect do NSAIDs have on the GI tract?
Increased risk of GI ulceration
What main effects does PGE2 have on the kidneys?
Increase renal blood flow
What effect do NSAIDs have on the kidneys?
Constriction of the afferent arteriole
Reduction in renal artery flow
Why should NSAIDs not be given to asthma patients?
Most prostaglandins are bronchodilators, so a reduction in prostaglandin production due to COX inhibition could exacerbate asthma
Furthermore, inhibition of COX favours the production of leukotrienes, which are bronchoconstrictors
Prostanoids are vasoregulators, so what are the consequences of NSAIDs on the cardiovascular system?
Increased risk of MI and stroke because chronic use of NSAIDs cause:
Small rise in blood pressure
Can reduce the effectiveness of anti-hypertensives
What is the difference in terms of risk of side effects when using NSAIDs for analgesic use compared to anti-inflammatory use?
Analgesic use – usually occasionally used so low risk of side effects
Anti-inflammatory use – often sustained use with higher doses = higher risk of side effects
Name two non-selective COX inhibitors.
Name a COX-2 selective inhibitor.
What is the major problem with COX-2 selective NSAIDs?
They have a significantly increased risk of cardiovascular disease than conventional NSAIDs
Describe the relative GI and CVS risks of COX-1 selective and COX-2 selective NSAIDs when compared to non-selective NSAIDs.
Same CVS risk as non-selective NSAIDs
Increased GI risk
Decreased GI risk
Increased CVS risk
What effect does ibuprofen have on the action of anti-hypertensive drugs?
It reduces the effectiveness of anti-hypertensive drugs It will reduce the drop in blood pressure that has been seen when the anti-hypertensives are used without ibuprofen
What are the potential reasons for increased risk of cardiovascular disease with non-selective and COX-2 selective NSAIDs?
Non-selective NSAIDs and COX-2 selective NSAIDs both increase cardiac work
Also, all NSAIDs produce oxygen free radicals, which can contribute to cardiovascular disease
State some strategies for avoiding/limiting the GI side effects of NSAIDs.
Use topical application
Minimise NSAID use in patients with a history of GI ulceration
Treat H. pylori if present
If NSAID is essential, administer omeprazole or another proton pump inhibitor
Minimise NSAID use in patients with other risk factors and reduce risk factors where possible e.g. alcohol consumption, anticoagulant use
Describe the action of aspirin.
It irreversibly binds to cox enzymes (binds covalently)
It is selective for COX-1