Which is a selective cyclo-oxygenase-2 inhibitor :
**Core Concept**
Selective cyclo-oxygenase-2 (COX-2) inhibitors are a class of nonsteroidal anti-inflammatory drugs (NSAIDs) that specifically target the COX-2 enzyme, which is involved in the inflammatory process, without affecting the COX-1 enzyme, which is responsible for protecting the stomach lining.
**Why the Correct Answer is Right**
The mechanism of action of selective COX-2 inhibitors involves the inhibition of the COX-2 enzyme, which is induced in response to inflammatory stimuli. This results in the reduction of prostaglandin synthesis, leading to decreased inflammation and pain. However, unlike non-selective NSAIDs, selective COX-2 inhibitors do not inhibit the COX-1 enzyme, which is essential for the production of protective prostaglandins in the stomach lining.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a non-selective COX inhibitor, which means it will inhibit both COX-1 and COX-2 enzymes, leading to increased risk of gastrointestinal side effects.
**Option B:** This option is incorrect because it is a traditional NSAID that does not have selective COX-2 inhibition, making it less suitable for patients at risk of gastrointestinal bleeding.
**Option C:** This option is incorrect because it is not a selective COX-2 inhibitor; instead, it is a traditional NSAID with non-selective COX inhibition.
**Clinical Pearl / High-Yield Fact**
Selective COX-2 inhibitors are preferred in patients with a history of gastrointestinal bleeding or those at high risk of developing gastrointestinal ulcers, as they reduce the risk of gastrointestinal side effects compared to non-selective NSAIDs.
**Correct Answer:** C. Celecoxib