Question

Which NSAID undergoes enterohepatic circulation?

• A. . Piroxicam
• B. . Ibuprofen
• C. . Aspirin
• D. . Phenylbutaxone

Hint:

Remember that enterohepatic circulation can significantly extend a drug's half-life and duration of action. For NSAIDs, ibuprofen is a key example of a drug that utilizes this pathway.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify which of the listed Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) undergoes enterohepatic circulation.

Step 3: Detailed Explanation:
* Enterohepatic circulation: This is the recirculation of substances (like drugs, bile acids) from the liver to the bile, then to the small intestine, and finally back to the liver via the portal vein. This process can prolong the half-life of a drug.
* Ibuprofen: Ibuprofen is known to undergo enterohepatic circulation. After absorption, it is metabolized in the liver, primarily by glucuronidation. These glucuronide conjugates are then excreted into the bile, re-enter the intestine, and can be deconjugated by gut bacteria, releasing free ibuprofen, which is then reabsorbed, thus prolonging its presence in the body.
* Piroxicam: While it has a long half-life, enterohepatic recirculation is not its primary characteristic.
* Aspirin (acetylsalicylic acid): It is rapidly hydrolyzed to salicylic acid, which is then excreted. It does not undergo significant enterohepatic circulation in its active form.
* Phenylbutazone: This is an older NSAID, known for serious side effects, and while it undergoes metabolism, enterohepatic circulation is not its defining pharmacokinetic feature in this context.
Therefore, Ibuprofen is the NSAID among the options that prominently undergoes enterohepatic circulation.

Step 4: Final Answer:
Ibuprofen undergoes enterohepatic circulation.

Answer 2

Enterohepatic circulation happens when a drug or its metabolite is sent into the bile, reaches the intestine, gets converted back into the active drug, and is absorbed again. Looking at how each of these NSAIDs is processed by the body shows which one fits this pattern.

1. Piroxicam: This drug is known for a very long half-life due to slow metabolism and strong binding to plasma proteins, but its long action is not because it recycles through bile and gut in the way enterohepatic circulation describes.
2. Ibuprofen: After being absorbed, ibuprofen is converted in the liver into glucuronide conjugates, which are released into bile and pass into the intestine. There, gut bacteria can break this conjugate apart, freeing active ibuprofen again, which the body reabsorbs. This repeating bile to gut to blood loop is the definition of enterohepatic circulation.
3. Aspirin: Aspirin is broken down quickly into salicylic acid, which is mostly cleared through the kidneys rather than being recycled through bile, so it does not show this pattern.
4. Phenylbutazone: This older NSAID is metabolised slowly and is known mainly for its side effect risks, but recycling through bile is not what defines its pharmacokinetics.

Since ibuprofen's glucuronide metabolite is specifically recycled through the bile and gut before being reabsorbed, it is the drug that undergoes enterohepatic circulation.

Therefore, the correct answer is Ibuprofen.