Prinivil / Zestril (Lisinopril) 2.5–40 mg Tablets: Prescription ACE Inhibitor for Hypertension, Chronic Heart Failure, Post-MI Cardioprotection, and Diabetic Nephroprotection — Not OTC

Information last reviewed: May 2026 — for educational purposes only.

Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor available under the brand names Prinivil and Zestril. It is the most widely prescribed ACE inhibitor in the United States and one of the most commonly used antihypertensive medications overall. By preventing the conversion of angiotensin I to angiotensin II, it reduces vasoconstriction and aldosterone secretion, lowering blood pressure and reducing cardiac workload.

Uses of Lisinopril

Lisinopril is approved for hypertension, heart failure with reduced ejection fraction (HFrEF — where it reduces mortality), post-myocardial infarction (started within 24 hours; reduces ventricular remodelling and mortality), diabetic nephropathy (renoprotective — reduces proteinuria and slows CKD progression), and asymptomatic left ventricular dysfunction. Zestoretic is a fixed-dose combination product containing lisinopril with hydrochlorothiazide for patients requiring both agents.

Mechanism, Warnings, and Key Interactions

Lisinopril inhibits ACE, the enzyme that converts angiotensin I to vasoconstrictive angiotensin II. This also reduces aldosterone secretion (lowering sodium and water retention) and increases bradykinin levels. Elevated bradykinin is responsible for the most common and well-known side effect: dry cough, occurring in 10–20% of patients, more commonly in women and Asian/Chinese patients. If the cough is intolerable, switching to an ARB such as losartan is standard practice. More seriously, lisinopril can cause angioedema — sudden swelling of the face, lips, tongue, or larynx — in 0.1–0.7% of patients. This is a medical emergency when the airway is involved. Risk is higher in Black patients and when combined with neprilysin inhibitors such as sacubitril. Lisinopril is contraindicated in pregnancy, in bilateral renal artery stenosis (it removes the efferent vasoconstriction that maintains GFR and can precipitate acute kidney injury), and in patients with a prior history of ACE inhibitor-induced angioedema. Hyperkalemia risk is elevated when combined with potassium-sparing diuretics, ARBs, aldosterone antagonists, or potassium supplements. Renal function and serum potassium should be checked one week after starting therapy.

Available Strengths and Dosing

Lisinopril tablets are available in 2.5 mg, 5 mg, 10 mg, 20 mg, and 40 mg strengths, taken once daily. The typical starting dose for hypertension is 10 mg once daily, titrated to effect. Heart failure treatment usually begins at 2.5–5 mg once daily. Post-MI treatment is initiated at 5 mg within 24 hours, with subsequent titration. The 2.5 mg dose is reserved for patients with volume depletion or renal impairment.

Pricing Overview

Generic lisinopril is one of the least expensive prescription medications available and is on most $4 generic formularies at major pharmacy chains. The branded Prinivil and Zestril carry higher costs. Zestoretic (lisinopril-HCTZ) is also available generically at low cost. Contact Lucas Clinic for current pricing and availability details.

Frequently Asked Questions

Is the dry cough from lisinopril dangerous, and will it go away?

The dry cough is a class effect of all ACE inhibitors caused by the accumulation of bradykinin. It is not dangerous in itself but can be persistent, disruptive, and is the leading reason patients discontinue ACE inhibitors. The cough will usually resolve within one to four weeks of stopping the medication. Switching to an ARB such as losartan or valsartan eliminates the cough while maintaining comparable antihypertensive and renoprotective effects, since ARBs do not affect bradykinin levels.

What is ACE inhibitor angioedema and who is most at risk?

Angioedema is a rapid, localised swelling of subcutaneous and submucosal tissue, typically affecting the face, lips, tongue, and throat. When it involves the larynx, it can obstruct the airway and become life-threatening within minutes. ACE inhibitor-induced angioedema occurs via bradykinin accumulation. It is more common in Black patients, can occur at any time during treatment (even after years of use), and is markedly more likely in patients also receiving neprilysin inhibitors (see sacubitril-valsartan). A prior episode of ACE inhibitor angioedema is an absolute contraindication to any ACE inhibitor.

Why is lisinopril beneficial after a heart attack?

After a myocardial infarction, the damaged heart muscle undergoes remodelling — changes in the size, shape, and function of the ventricle that often worsen cardiac function over time. Lisinopril, when started within 24 hours of an MI, reduces this ventricular remodelling by lowering the mechanical stress on the healing myocardium and blocking the fibrogenic effects of angiotensin II. Clinical trials have demonstrated a statistically significant reduction in mortality when ACE inhibitors are initiated early post-MI, particularly in patients with reduced ejection fraction.

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