Question

All of these are pro-drugs except

• A. Enalapril
• B. Lisinopril
• C. Benazepril
• D. Ramipril

Hint:

Lisinopril and Captopril are the two classic, standard ACE inhibitors that are not prodrugs. They do not require the liver to become active, making them useful in patients with hepatic insufficiency.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A prodrug is a biologically inactive compound that must be metabolized within the body (usually by hepatic enzymes) to produce the active therapeutic drug.
Detailed Explanation:
Let us examine the pharmacology of angiotensin-converting enzyme (ACE) inhibitors:
- Most ACE inhibitors are formulated as ester prodrugs to improve their oral absorption and bioavailability.
- Enalapril, Benazepril, and Ramipril are inactive prodrugs. They must undergo hepatic esterase cleavage to be converted into their active metabolites: enalaprilat, benazeprilat, and ramiprilat, respectively.
- Lisinopril (along with Captopril) is a notable exception. It is already in its active form when administered and does not require hepatic metabolism to exert its therapeutic effects. It is excreted unchanged by the kidneys.

Step 2: Final Answer:
Lisinopril is not a prodrug, which corresponds to Option (B).