Which medication is most likely causing a persistent, dry cough in a hypertensive patient taking clonidine, amlodipine, and lisinopril?

The medication most likely causing a persistent, dry cough in a hypertensive patient is lisinopril. This is because lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, which is known to cause a cough as a common side effect in some patients. The cough may be related to the accumulation of bradykinin, a peptide that can increase in the body when ACE is inhibited, leading to irritation of the respiratory tract.

Amlodipine, a calcium channel blocker, does not typically cause cough and is generally well-tolerated in this regard. Clonidine is an alpha-2 adrenergic agonist and is not associated with cough as a common side effect. Aspirin is an antiplatelet medication and not known to induce cough in hypertensive patients.

Therefore, based on the known side effect profile of lisinopril, it is the medication responsible for the persistent, dry cough in this scenario.