## **Core Concept**
ACE inhibitors are a class of medications used primarily to treat hypertension and heart failure. They work by inhibiting the angiotensin-converting enzyme (ACE), which is involved in the renin-angiotensin-aldosterone system (RAAS). Some ACE inhibitors are prodrugs, meaning they require metabolic activation in the body to exert their therapeutic effect.

## **Why the Correct Answer is Right**
The correct answer, , is not a prodrug. This means it does not require metabolic conversion to an active form to exert its ACE inhibitory effect. Unlike prodrugs, which are inactive in their administered form, is active as administered.

## **Why Each Wrong Option is Incorrect**
- **Option A:** is a prodrug. It requires conversion to its active form to exert its therapeutic effect.
- **Option B:** is also a prodrug. It needs to be metabolized into its active form.
- **Option C:** is another prodrug. Its therapeutic effect is realized after metabolic activation.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while prodrugs are inactive until metabolized, their use can be beneficial in certain clinical scenarios, such as improving bioavailability. Knowing which ACE inhibitors are prodrugs can be crucial for patients with liver or kidney impairment, as their metabolism and activation might be affected.

## **Correct Answer:** . Lisinopril