Lisinopril (Prinivil, Zestril) is an ACE inhibitor used to treat high blood pressure, heart failure with reduced ejection fraction, and to protect the kidneys in diabetic patients. It works by blocking angiotensin-converting enzyme, preventing formation of the vasoconstrictor angiotensin II, which relaxes blood vessels and reduces aldosterone secretion. Common side effects include a persistent dry cough (in 10–15% of patients), dizziness, and elevated potassium. It is absolutely contraindicated in pregnancy due to fetal toxicity risk, and can cause life-threatening angioedema — swelling of the lips, tongue, or throat — requiring immediate emergency care.
Lisinopril
Uses & Indications
Lisinopril is one of the most widely prescribed drugs in the United States, used across several cardiovascular and renal conditions. Its FDA-approved indications include: hypertension (high blood pressure), heart failure with reduced ejection fraction (HFrEF), and acute myocardial infarction (heart attack) to reduce cardiovascular mortality when started within 24 hours.
Off-label but guideline-recommended uses include diabetic nephropathy — kidney disease caused or worsened by diabetes — where ACE inhibitors are strongly preferred because of their specific renal protective mechanism. They are also used in non-diabetic chronic kidney disease with significant proteinuria, and in patients with left ventricular dysfunction following MI.
How It Works
Lisinopril inhibits angiotensin-converting enzyme (ACE), a key enzyme in the renin-angiotensin-aldosterone system (RAAS). When the kidneys detect low blood pressure or low sodium, they release renin, which cleaves angiotensinogen to angiotensin I. ACE then converts angiotensin I to angiotensin II — the potent vasoconstrictor and aldosterone stimulator at the center of blood pressure regulation.
By blocking ACE, lisinopril prevents angiotensin II formation. The downstream consequences are: vasodilation (both arterial and venous), reduced aldosterone secretion (less sodium and water retention, less potassium loss), and reduced sympathetic activation. Blood pressure falls through both reduced vascular resistance and reduced volume.
Kidney Protection Mechanism
Lisinopril's renal benefit goes beyond blood pressure lowering. In diabetic nephropathy, the efferent arteriole of the glomerulus is preferentially constricted by angiotensin II, which maintains glomerular filtration pressure but causes damaging intraglomerular hypertension. ACE inhibition dilates the efferent arteriole, reducing intraglomerular pressure, decreasing proteinuria, and slowing the progression of kidney damage — an effect largely independent of its systemic blood pressure effect.
Lisinopril also inhibits ACE's secondary role as a bradykinin-degrading enzyme (kininase II). Accumulated bradykinin contributes to vasodilation (beneficial) but also causes the well-known dry cough and, rarely, angioedema (problematic). This is a class effect of all ACE inhibitors — switching to a different ACE inhibitor will not eliminate it.
Side Effects
Common
- Dry, persistent cough — the most common reason for discontinuation, affecting 10–15% of patients (higher in Asian and East African populations). Caused by bradykinin accumulation. Not dangerous but can be bothersome. Switching to an ARB (e.g., losartan, valsartan) eliminates the cough because ARBs do not affect bradykinin.
- Dizziness / hypotension — especially with first dose, in volume-depleted patients, or with diuretics
- Elevated potassium (hyperkalemia) — reduced aldosterone means less potassium excretion
- Mild rise in serum creatinine — expected (reflects efferent dilation, not true kidney damage in most cases); a rise >30% warrants investigation
- Headache, fatigue
Serious
- Angioedema — rapid, potentially life-threatening swelling of lips, tongue, throat, or face. Can occur at any point during treatment, even years after starting. Black patients have 3–5x higher incidence. Absolute contraindication to rechallenge with any ACE inhibitor.
- Severe hyperkalemia — life-threatening cardiac arrhythmia risk, particularly in patients with CKD, diabetes, or on potassium-sparing agents
- Acute kidney injury — particularly with bilateral renal artery stenosis (where GFR is entirely dependent on angiotensin II-mediated efferent constriction)
Drug Interactions
| Drug / Class | Interaction | Clinical Significance |
|---|---|---|
| NSAIDs (ibuprofen, naproxen) | NSAIDs blunt ACE inhibitor's antihypertensive effect and, combined with RAAS blockade, can cause acute kidney injury — the "triple whammy" with diuretics. Even short OTC NSAID use raises blood pressure in hypertensive patients. | High — avoid combination; use acetaminophen for pain |
| Potassium-sparing diuretics (spironolactone, eplerenone, amiloride) | Both mechanisms reduce potassium excretion. Combination raises serious hyperkalemia risk, particularly in patients with CKD or diabetes. | High — monitor potassium and renal function closely; combination sometimes used intentionally in heart failure with careful monitoring |
| Lithium | ACE inhibitors reduce renal sodium excretion, which triggers compensatory lithium reabsorption and raises lithium levels. Lithium toxicity risk is significant. | High — monitor lithium levels frequently when starting or stopping lisinopril |
| Aliskiren (direct renin inhibitor) | Dual RAAS blockade — combining aliskiren with ACE inhibitor — significantly increases hyperkalemia, hypotension, and renal impairment risk. Contraindicated in patients with diabetes or eGFR <60. | High — avoid combination in most patients |
| Sacubitril/Valsartan (Entresto) | Entresto contains an ARB (valsartan) not an ACE inhibitor — important distinction. However, sacubitril inhibits neprilysin, which normally degrades bradykinin. Using an ACE inhibitor with sacubitril dramatically increases bradykinin levels, raising angioedema risk substantially. Must wait 36 hours after stopping ACE inhibitor before starting Entresto. | High — 36-hour washout period required; do not co-administer |
| Potassium supplements / Salt substitutes | Many salt substitutes (e.g., NoSalt, Nu-Salt) contain potassium chloride instead of sodium chloride. Combined with ACE inhibitor-induced potassium retention, this can cause dangerous hyperkalemia. | Moderate — counsel patients to avoid potassium-containing salt substitutes |
Warnings & Contraindications
Absolute Contraindications
- Pregnancy (any trimester)
- History of angioedema related to ACE inhibitor therapy
- Hereditary or idiopathic angioedema
- Concomitant use of aliskiren in patients with diabetes
- Concomitant use with sacubitril (without 36-hour washout)
Monitor Closely In
- Bilateral renal artery stenosis or single kidney with renal artery stenosis
- Significant aortic or mitral valve stenosis
- Hyperkalemia at baseline or with impaired renal function
- Volume-depleted or sodium-depleted patients — start at low dose
Check if lisinopril interacts with your other blood pressure or heart medications.
Check Drug Interactions →Frequently Asked Questions
Can I take ibuprofen or naproxen with lisinopril?
This combination should be avoided when possible. NSAIDs blunt lisinopril's blood pressure-lowering effect — studies show regular NSAID use can raise systolic BP by 3–5 mmHg even in well-controlled hypertension. More importantly, the combination can cause acute kidney injury, especially in patients who are dehydrated, elderly, or also taking a diuretic. Acetaminophen is a much safer analgesic choice for most lisinopril patients.
Why do I have a cough on lisinopril?
The cough is caused by accumulation of bradykinin — a peptide that ACE normally breaks down. When ACE is blocked, bradykinin builds up in the respiratory tract and triggers a tickling, persistent, dry cough in 10–15% of patients. It is a class effect: switching to a different ACE inhibitor will not resolve it. The solution is switching to an angiotensin receptor blocker (ARB) such as losartan or valsartan, which block the same RAAS pathway downstream of ACE without affecting bradykinin. ARBs provide essentially equivalent antihypertensive and renoprotective benefit.
What should I do if I miss a dose?
Take the missed dose as soon as you remember, unless it is close to the time for your next dose — in that case, skip the missed dose and resume your normal schedule. Do not double up. Lisinopril's 12-hour half-life means that a single missed dose rarely causes a clinically meaningful rebound in blood pressure for most patients, but consistent daily dosing is important for stable long-term control.
What if I develop swelling of my lips or tongue?
Stop lisinopril immediately and seek emergency medical care. Swelling of the lips, tongue, throat, or face is angioedema — a potentially life-threatening allergic-type reaction that can obstruct the airway. It can occur unpredictably at any point during treatment. After confirmed ACE inhibitor-induced angioedema, you must never take another ACE inhibitor. Carry documentation of this reaction and ensure it is prominently flagged in your medical records.