Final answer:
Captopril, an ACE inhibitor used to treat hypertension, is likely the medication causing the patient’s cough due to the buildup of bradykinin in the lungs, a recognized side effect of this class of drugs.
Step-by-step explanation:
A patient with hypertension (HTN) comes in and mentions that a new medication is causing him to cough. Among the list of his medications, Captopril is the most likely culprit for the cough. Captopril is an angiotensin converting enzyme (ACE) inhibitor, which is a class of medication commonly used to treat high blood pressure. A well-known side effect of ACE inhibitors is a persistent dry cough due to the buildup of bradykinin in the lungs. While other medications listed such as Metoprolol, Clopidogrel, and Tadalafil have their own side effect profiles, they do not commonly cause cough as a side effect.
ACE inhibitors like Captopril are designed to block the conversion of angiotensin I to angiotensin II, reducing the latter's ability to constrict blood vessels and thus lower blood pressure. However, they can also hinder the breakdown of bradykinin, which can accumulate and stimulate the lungs leading to coughing. Understanding this side effect is vital for both patients and healthcare providers to manage the symptoms effectively or to consider alternative treatments if necessary.