16 Questions
What is the primary function of COX-1 in the stomach?
Producing PGE2 to provide a protective effect
Which of the following NSAIDs is known to cause irreversible covalent modification?
Aspirin
What is the primary mechanism of action of Paracetamol?
Unknown, but it may involve multiple mechanisms
What is the main difference between COX-1 and COX-2 in terms of their structure?
COX-1 has a smaller hydrophobic channel
Which of the following is a potential side effect of NSAIDs?
Increased risk of cardiovascular disease
What is the main difference between COX-1 and COX-2 in terms of their expression?
COX-1 is constitutive, while COX-2 is inducible
What is the primary function of the lipid mediators mentioned in the text?
To resolve inflammation
What is the target of NSAIDs according to the text?
Cyclooxygenase
COX-1 is primarily found in the CNS and produces PGI2 to prevent platelet aggregation.
False
All NSAIDs are selective for COX-2.
False
Paracetamol is an NSAID.
False
COX-2 is constitutively expressed and found in endothelial cells.
False
GI bleeding is a possible side effect of NSAIDs.
True
Rofecoxib is a non-selective NSAID.
False
Cyclooxygenase is a pro-resolution lipid mediator.
False
NSAIDs are selective inhibitors of COX-2.
False
Study Notes
Cyclooxygenase Enzyme
- Produces PGG2 and PGH2
- Has two subtypes: COX-1 and COX-2
COX-1 Subtype
- Constitutive and widespread
- Produces PGE2 in the stomach, which is protective
- Found in platelets, where it produces TXA2 for aggregation
- Has a small hydrophobic channel, which can be inhibited by small molecules
COX-2 Subtype
- Inducible, with synthesis increased by cytokines
- Produces high levels of PGs in areas of inflammation
- Found in endothelial cells, where it produces PGI2 to prevent aggregation, and in the CNS
- Has a larger channel, which can be inhibited by drugs with bulky side groups that cannot enter COX-1
NSAIDS (Non-steroidal Anti-inflammatory Drugs)
- Non-selective (COX-1 and COX-2) inhibitors:
- Aspirin (irreversible covalent modification)
- Ibuprofen (reversible)
- Ketorolac
- Flurbiprofen
- COX-2 selective (generally reversible) inhibitors:
- Celecoxib
- Rofecoxib
- Side effects: GI bleeding, possible increased cardiovascular risk
Paracetamol
- Not an anti-inflammatory drug
- Several proposed mechanisms of action, including:
- COX-3 in CNS
- Decrease nitrox oxide synthesis in spinal cord
- Metabolite NAPQI inhibiting neurotransmission
- Antipyretic analgesic, extremely safe and well-tolerated
- Given for a wide range of conditions
- Liver toxicity a concern
Learn about the cyclooxygenase enzyme, its subtypes COX-1 and COX-2, and their roles in inflammation and platelet aggregation. Understand how they produce prostaglandins and thromboxane, and how they can be inhibited by small molecules. This quiz covers the basics of cyclooxygenase as a drug target.
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