What is the most common side effect of ACE inhibitors and why does it occur?

The most common side effect of ACE inhibitors is a persistent dry cough, occurring in 5 to 20 percent of patients. It happens because ACE inhibitors prevent the breakdown of bradykinin, a peptide that accumulates in the lungs and irritates airway sensory nerves. The cough is nonproductive, often worse at night, and resolves within one to four weeks after discontinuing the medication. Patients who cannot tolerate the cough are typically switched to an angiotensin two receptor blocker, or ARB, which does not affect bradykinin levels and rarely causes cough.