Pharmacology · patient case question
What is the mechanism of action of lisinopril?
Patient case: Reviewing a long medication list
Patient: Female, 55 years old
Chief Complaint: Presents for a comprehensive examination.
Background: Graves disease, hypertension, asthma. She carries a naloxone kit because a family member has opioid use disorder.
Medications: Propylthiouracil · lisinopril · albuterol inhaler · naloxone (rescue kit)
Vital Signs: BP 132/84 mmHg · HR 84 bpm · RR 16
Show answer and explanation
Correct answer: C. Inhibits angiotensin-converting enzyme
- A. Angiotensin II receptor blockade is the ARBs — losartan, valsartan. They are the substitution when an ACE inhibitor cough is intolerable, because they do not raise bradykinin.
- B. The distal tubule sodium-chloride cotransporter is inhibited by THIAZIDE diuretics such as hydrochlorothiazide.
- C. CORRECT. Lisinopril is an ACE INHIBITOR. Blocking ACE prevents conversion of angiotensin I to angiotensin II, lowering vasoconstriction and aldosterone-driven sodium retention. The same enzyme degrades bradykinin, so bradykinin accumulates — which explains both the dry cough seen in up to a fifth of patients and the rare but dangerous angioedema. Lisinopril is also unusual among ACE inhibitors in not being a prodrug.
- D. Beta-1 blockade is metoprolol and atenolol — a different antihypertensive class entirely.
Note: Worth circulating to the group: at least three files in this series key lisinopril as a diuretic. It is an ACE inhibitor.