Enalapril

Generic Name: Enalapril

Brand Names: Vasotec

Enalapril is an ACE inhibitor used to treat high blood pressure and heart failure. It works by relaxing blood vessels and reducing strain on the heart.

CardiovascularACE InhibitorsHypertensionHeart Failure

Drug Class

Angiotensin-Converting Enzyme (ACE) Inhibitor

Pregnancy

Category D — Drugs acting on the renin-angiotensin system during the second and third trimesters cause fetal renal dysfunction, oligohydramnios, skull hypoplasia, and death. Discontinue enalapril as soon as pregnancy is detected. FDA Boxed Warning applies.

Available Forms

Oral tablet (2.5 mg, 5 mg, 10 mg, 20 mg), Oral solution (1 mg/mL — Epaned), IV injection (1.25 mg/mL enalaprilat — Vasotec IV)

What It's Used For

Hypertension in adults and children
Heart failure mortality reduction
Asymptomatic left ventricular dysfunction
Diabetic nephropathy protection
Cardiovascular risk reduction

Dosage Quick Reference

These are general dosage guidelines. Your doctor will determine the appropriate dose for your specific situation.

Condition	Starting Dose	Maintenance Dose
Hypertension (adults)	5 mg orally once daily	10–40 mg/day in 1–2 divided doses; max 40 mg/day
Hypertension (with diuretic)	2.5 mg orally once daily	Titrate slowly to avoid first-dose hypotension
Symptomatic heart failure	2.5 mg orally twice daily	Target 10–20 mg twice daily; max 40 mg/day
Asymptomatic LV dysfunction	2.5 mg orally twice daily	10 mg twice daily
Pediatric hypertension (>= 1 month)	0.08 mg/kg once daily (max 5 mg)	Titrate to response; max 0.58 mg/kg or 40 mg/day

Side Effects

Common Side Effects:

Dry, persistent cough
Dizziness
Headache
Fatigue
Nausea
Diarrhea
Rash

Serious Side Effects (seek immediate medical attention):

Swelling of face, lips, tongue, or throat (angioedema)
Difficulty breathing or swallowing
Signs of high potassium (weakness, slow heartbeat, muscle paralysis)
Signs of kidney problems (decreased urination, swelling)
Severe hypotension (fainting, dizziness)

Drug Interactions

Enalapril blocks the renin-angiotensin-aldosterone system and has several clinically important interactions.

Potassium-sparing diuretics, potassium supplements, salt substitutes (e.g., spironolactone, eplerenone): Additive hyperkalemia risk. Monitor serum potassium, particularly in patients with renal impairment or diabetes.
NSAIDs (e.g., ibuprofen, naproxen, celecoxib): NSAIDs reduce the antihypertensive and renoprotective effects of ACE inhibitors and increase the risk of acute kidney injury, especially in elderly or volume-depleted patients. Use lowest effective NSAID dose for shortest duration.
Aliskiren: Dual RAAS blockade increases the risk of hyperkalemia, hypotension, and renal impairment. Concurrent use is contraindicated in patients with diabetes or renal impairment (GFR < 60 mL/min).
Lithium: Enalapril reduces lithium clearance, raising the risk of lithium toxicity. Monitor lithium levels closely.
Sacubitril/valsartan: Concurrent use is contraindicated due to increased angioedema risk. Allow at least 36 hours between discontinuing enalapril and starting sacubitril/valsartan.
mTOR inhibitors (sirolimus, everolimus) and DPP-4 inhibitors (sitagliptin, saxagliptin): May increase the risk of angioedema when combined with ACE inhibitors.

Additional Information

Enalapril is an angiotensin-converting enzyme (ACE) inhibitor that has been a cornerstone of cardiovascular medicine for decades. By blocking the conversion of angiotensin I to angiotensin II, it provides effective treatment for hypertension, heart failure, and asymptomatic left ventricular dysfunction, with proven benefits for reducing cardiovascular morbidity and mortality.

Mechanism of Action

Enalapril is a prodrug that is hydrolyzed in the liver to its active form, enalaprilat. Enalaprilat inhibits angiotensin-converting enzyme (ACE), preventing the conversion of angiotensin I to the potent vasoconstrictor angiotensin II. This results in decreased aldosterone secretion, reduced sodium and water retention, and vasodilation. Additionally, ACE inhibition decreases the breakdown of bradykinin, a vasodilator peptide, which contributes to the blood pressure-lowering effect but may also be responsible for the characteristic dry cough that occurs in some patients.

The neurohormonal modulation provided by ACE inhibitors extends beyond blood pressure control. In heart failure, enalapril reduces preload and afterload, decreases ventricular remodeling, and provides long-term cardiovascular protection that translates to improved survival and reduced hospitalizations.

Available Formulations

Enalapril maleate is available as oral tablets in 2.5 mg, 5 mg, 10 mg, and 20 mg strengths. Enalaprilat, the active metabolite, is available as an injectable solution (1.25 mg/mL) for intravenous use when oral administration is not feasible. A combination product with hydrochlorothiazide (Vaseretic) is available for patients requiring dual therapy.

FDA-Approved Indications

Enalapril is FDA-approved for hypertension in adults and pediatric patients one month of age and older, symptomatic heart failure (to reduce mortality and hospitalizations), and asymptomatic left ventricular dysfunction with ejection fraction 35% or less (to decrease rate of development of overt heart failure and reduce hospitalization for heart failure). These broad indications reflect the extensive clinical trial evidence supporting the cardiovascular benefits of ACE inhibition.

Dosing Guidelines

For hypertension, the typical starting dose is 5 mg once daily, with a usual dose range of 10-40 mg daily in one or two divided doses. For heart failure, start with 2.5 mg once or twice daily, titrating gradually to target doses of 10-20 mg twice daily as tolerated. Lower starting doses (2.5 mg) are recommended for patients with renal impairment, those on diuretics, or those at risk for hypotension. Monitor blood pressure, renal function, and potassium levels, especially during dose initiation and titration.

Clinical Trial Evidence

Enalapril has been studied extensively in landmark clinical trials that established the role of ACE inhibitors in cardiovascular medicine. The CONSENSUS and SOLVD trials demonstrated mortality reduction in heart failure. The SOLVD Prevention trial showed benefits in asymptomatic LV dysfunction. These trials, along with extensive post-marketing experience, have made enalapril one of the most well-characterized cardiovascular medications.

Important Safety Considerations

Enalapril carries a boxed warning for fetal toxicity; it should be discontinued immediately when pregnancy is detected due to risks of fetal injury and death. Angioedema can occur, particularly affecting the face, lips, tongue, and larynx, and may be life-threatening; it is more common in African American patients. Hyperkalemia may develop, especially in patients with renal impairment or those taking potassium supplements or potassium-sparing diuretics. Hypotension may occur, particularly with first doses in patients who are volume-depleted.

Drug Interactions

NSAIDs can reduce the antihypertensive effect and increase the risk of renal impairment. Potassium supplements and potassium-sparing diuretics increase the risk of hyperkalemia. Lithium levels may increase; monitor closely. Dual blockade of the renin-angiotensin system with ARBs or aliskiren is generally not recommended due to increased risks of hypotension, hyperkalemia, and renal impairment. Diuretics may enhance hypotensive effects.

Special Populations

Dose reduction is required in renal impairment based on creatinine clearance. Use with caution in patients with bilateral renal artery stenosis or stenosis in a solitary kidney due to risk of acute renal failure. Enalapril is contraindicated during pregnancy. Safety and dosing have been established in pediatric patients one month of age and older for hypertension. Elderly patients may require lower starting doses due to age-related decreases in renal function.

Learn more at MedlinePlus

Frequently Asked Questions

ACE inhibitors block the breakdown of bradykinin and substance P, which can accumulate in the airway and trigger a persistent dry, tickling cough in 5 to 20 percent of patients. The cough typically begins within weeks to months of starting therapy and resolves within 1 to 4 weeks of discontinuation. If bothersome, your doctor can switch you to an angiotensin receptor blocker (ARB), which does not affect bradykinin.

Angioedema is sudden swelling of the lips, tongue, throat, or face caused by bradykinin accumulation. Although uncommon (about 0.1 to 0.7 percent of users), it can be life-threatening if it compromises the airway. Stop enalapril immediately and seek emergency care if you notice any swelling. Patients with prior ACE inhibitor angioedema should generally avoid all ACE inhibitors permanently.

In most patients, enalapril actually protects the kidneys — particularly in diabetes and proteinuric kidney disease — by lowering intraglomerular pressure. A small rise in creatinine (up to 30 percent) within the first 1 to 2 weeks is expected and not a reason to stop the drug. Larger rises, or use in patients with bilateral renal artery stenosis, can cause acute kidney injury. Routine monitoring catches problems early.

Yes. Home blood pressure monitoring helps confirm that your medication is working and detects excessive drops or rebound elevations. Take readings at the same times each day (typically morning and evening), use a validated upper-arm cuff, and bring your log to office visits. Most patients should aim for readings below 130/80 mmHg, but your individual target may differ.

Yes, food does not significantly affect enalapril absorption. Many patients find it easier to remember by taking it at the same time each day, with or without a meal. Consistency matters more than timing relative to food.

A basic metabolic panel checked 1 to 2 weeks after starting enalapril (and after dose changes) screens for hyperkalemia and acute changes in kidney function. Stable patients are then typically rechecked every 6 to 12 months. These labs are quick and inexpensive but catch silent problems before they become dangerous.

Questions to Ask Your Doctor

Consider discussing these topics at your next appointment:

✓What blood pressure target are we aiming for, and how should I monitor at home?
✓When will my next blood test be, and what are we checking?
✓Are any of my other medications likely to interact with enalapril?
✓What symptoms should make me stop the medication and call you immediately?
✓If I develop a cough, is switching to an ARB an option for me?

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Related Health Conditions

This medication is commonly used to treat or manage the following conditions:

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Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.