What is the likely cause of a persistent dry cough in a patient initiated on hypertension therapy?

The persistent dry cough is most likely caused by lisinopril, which is an angiotensin-converting enzyme (ACE) inhibitor commonly used in the treatment of hypertension. ACE inhibitors work by inhibiting the conversion of angiotensin I to angiotensin II, leading to vasodilation and reduced blood pressure. However, a significant side effect associated with ACE inhibitors is the development of cough. This occurs due to the accumulation of bradykinin, which is not broken down as effectively when ACE is inhibited. The increased bradykinin levels can lead to irritation of the respiratory tract, resulting in a characteristic dry cough.

In contrast, the other medications listed—losartan, nifedipine, and atenolol—are less commonly associated with causing a dry cough. Losartan is an angiotensin II receptor blocker (ARB) that does not have the same effect on bradykinin levels, and therefore does not typically cause cough. Nifedipine is a calcium channel blocker that primarily causes vasodilation by inhibiting calcium influx; it is not linked to respiratory side effects. Atenolol, a beta-blocker, acts primarily by reducing heart rate and contractility and does not typically cause cough as a