Which of the following is a Neprilysin inhibitor?
**Core Concept**
Neprilysin is a metalloprotease enzyme involved in the degradation of various peptides, including natriuretic peptides, bradykinin, and substance P, which play crucial roles in cardiovascular and renal function. Inhibiting neprilysin can lead to increased levels of these peptides, resulting in vasodilation, natriuresis, and diuresis.
**Why the Correct Answer is Right**
Sacubitril is a neprilysin inhibitor that, when used in combination with valsartan, forms the angiotensin receptor-neprilysin inhibitor (ARNI) class of drugs. By inhibiting neprilysin, sacubitril increases the levels of natriuretic peptides, which then bind to their receptors, leading to vasodilation and decreased blood pressure. This mechanism is particularly beneficial in patients with heart failure, as it not only lowers blood pressure but also improves cardiac function.
**Why Each Wrong Option is Incorrect**
**Option A:** Enalapril is an angiotensin-converting enzyme (ACE) inhibitor, which blocks the conversion of angiotensin I to angiotensin II, leading to vasodilation and decreased blood pressure. While it is used to treat hypertension and heart failure, it does not inhibit neprilysin.
**Option B:** Lisinopril is also an ACE inhibitor, similar to enalapril, and is used to treat hypertension and heart failure. It does not have neprilysin inhibitory activity.
**Option C:** Losartan is an angiotensin II receptor blocker (ARB), which blocks the action of angiotensin II on its receptors, leading to vasodilation and decreased blood pressure. It does not inhibit neprilysin.
**Clinical Pearl / High-Yield Fact**
Sacubitril-valsartan is a unique combination therapy that not only lowers blood pressure but also improves cardiac function in patients with heart failure. Its neprilysin inhibitory activity makes it an attractive option for patients who are resistant to or intolerant of traditional ACE inhibitors or ARBs.
**Correct Answer: C. Sacubitril**