Vignette: A 55-year-old man presents to the clinic with a 3-month history of increasing shortness of breath and fatigue. He has a history of hypertension and type 2 diabetes mellitus that are well controlled on medication. His physical examination reveals jugular venous distension, bilateral lower limb edema, and a gallop rhythm on auscultation of the heart. Echocardiography shows a dilated left ventricle with reduced ejection fraction. The patient is diagnosed with congestive heart failure. His physician prescribes a medication that reduces mortality in patients with heart failure. This drug works by inhibiting the action of an enzyme that converts an inactive decapeptide to an active octapeptide in the lungs. Which of the following is the most likely drug prescribed to this patient?
Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, widely used in the management of congestive heart failure. ACE inhibitors work by blocking the conversion of angiotensin I (an inactive decapeptide) to angiotensin II (an active octapeptide) in the lungs. Angiotensin II is a potent vasoconstrictor and promotes the release of aldosterone, which further contributes to fluid retention. By inhibiting the formation of angiotensin II, ACE inhibitors help to reduce vasoconstriction and fluid retention, thereby reducing the workload on the heart. Multiple studies have shown that ACE inhibitors can reduce mortality in patients with heart failure. Other medications used in heart failure management include beta-blockers (e.g., metoprolol), diuretics (e.g., furosemide), cardiac glycosides (e.g., digoxin), and aldosterone antagonists (e.g., spironolactone), but none of these drugs work by the mechanism described in the question.