A 52-year-old man with chronic heart failure (NYHA Class III) is started on an ACE inhibitor. Which is the most common adverse effect that limits long-term use of ACE inhibitors in heart failure patients?

Explanation

## Most Common Adverse Effect of ACE Inhibitors **Key Point:** Persistent dry cough occurs in 5–10% of patients on ACE inhibitors and is the most common reason for drug discontinuation, though it is not life-threatening. ### Mechanism of Cough ACE inhibitors block the conversion of angiotensin I to angiotensin II. This leads to: 1. Accumulation of **bradykinin** (a potent inflammatory mediator) 2. Bradykinin stimulates cough receptors in the respiratory tract 3. Cough is typically dry, persistent, and occurs within weeks of initiation ### Comparison of ACE Inhibitor Adverse Effects | Adverse Effect | Incidence | Severity | Clinical Significance | |---|---|---|---| | Dry cough | 5–10% | Mild–moderate | Most common cause of discontinuation | | Hyperkalemia | 1–2% | Potentially serious | Risk increases with renal impairment, NSAIDs, K-sparing diuretics | | Angioedema | 0.1–0.2% | Life-threatening | Rare; contraindication to ACE inhibitors | | First-dose hypotension | Variable | Usually mild | More common in volume-depleted patients; managed by dose adjustment | **Clinical Pearl:** The cough is **reversible** upon discontinuation and does not indicate organ damage. Switching to an ARB (angiotensin II receptor blocker) is the standard alternative, as ARBs do not accumulate bradykinin and cough incidence is <2%. **High-Yield:** In NEET PG exams, when asked about the "most common" adverse effect of ACE inhibitors in heart failure, the answer is **dry cough**. Hyperkalemia and angioedema are serious but less frequent; first-dose hypotension is usually transient and manageable.