Among the following drugs, ACE inhibitor with longest half life is:
**Core Concept**
ACE inhibitors are a class of drugs used to treat hypertension and heart failure by blocking the action of angiotensin-converting enzyme (ACE), which converts angiotensin I to angiotensin II, a potent vasoconstrictor. The half-life of an ACE inhibitor is an important pharmacokinetic property that determines its dosing frequency.
**Why the Correct Answer is Right**
Enalapril is an ACE inhibitor with a unique property of being a prodrug, which is metabolized to its active form, enalaprilat, in the liver. Enalaprilat has a longer half-life compared to other ACE inhibitors, ranging from 11 to 39 hours, making it suitable for once-daily dosing. This prolonged half-life allows for more consistent blood pressure control and improved patient compliance.
**Why Each Wrong Option is Incorrect**
**Option A:** Lisinopril has a half-life of approximately 12 hours, which is shorter than enalapril.
**Option B:** Captopril has a half-life of about 2 hours, which requires more frequent dosing.
**Option C:** Ramipril has a half-life of around 2-4 hours, similar to captopril, and is not as long-acting as enalapril.
**Clinical Pearl / High-Yield Fact**
When choosing an ACE inhibitor, consider the patient's renal function, as some drugs, like captopril, may accumulate in renal failure and increase the risk of hyperkalemia.
**Correct Answer: C. Enalapril.**