Enalapril dosage, forms, and strengths

Enalapril is a commonly prescribed blood pressure and heart failure medication. As an ACE inhibitor, it dilates blood vessels, lowering blood pressure. Depending on the prescription, doses are taken once or twice daily.

Enalapril forms and strengths

Enalapril only comes in oral dosage formats, either tablets or oral solution. 

• Tablet: 2.5 mg, 5 mg, 10 mg, 20 mg

• Oral solution (liquid): 1 mg/mL

Enalapril dosage for adults

The FDA has approved enalapril as a treatment for high blood pressure (hypertension), heart failure, and an early stage of heart failure called asymptomatic left ventricular dysfunction. 

Enalapril is a safe drug, but not for everyone. Healthcare professionals cannot safely use it in people who have a history of angioedema (swelling of the lips, face, neck, or head) or allergic reactions to enalapril or other ACE inhibitors. It’s also contraindicated in people with hereditary angioedema or unexplained facial swelling.

Though not prohibited, healthcare professionals avoid ACE inhibitors in pregnant women because they can harm an unborn baby.

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Enalapril dosage for hypertension

High blood pressure affects 47% of the adult American population, particularly older Americans. It is a symptomless but potentially devastating condition that slowly damages blood vessels and vital organs.

Angiotensin-converting enzyme inhibitors (ACE inhibitors) like enalapril are among the most commonly prescribed treatments for hypertension. These drugs block an enzyme that synthesizes angiotensin II, a hormone that tightens and narrows blood vessels. By blocking this enzyme, enalapril causes blood vessels to dilate, allowing more blood to flow through them at a lower pressure. 

Doctors have several medications in the ACE inhibitors family to choose from. They are more or less equal in their antihypertensive effect. The most commonly used are benazepril, lisinopril, and enalapril. Doctors often prescribe ACE inhibitors along with other blood pressure medications, such as hydrochlorothiazide, to help bring blood pressure into the normal range. Make sure to take those other drugs as instructed.

• Standard adult dosage of enalapril for hypertension: 10–40 mg daily taken as a single or divided dose

• Maximum adult dosage of enalapril for hypertension: 40 mg daily

Enalapril dosage for heart failure

Congestive heart failure is a severe and often progressive condition that affects about 5.7 million Americans. A heart fails when it can’t pump enough blood to the rest of the body. The heart works harder to compensate, and the heart muscle grows thicker. The thicker muscle allows the heart to beat with more strength but decreases the chamber size inside. When the heart can’t fill with as much blood as the body needs, heart failure results. This downward spiral can continue until the heart is so inefficient at pumping blood that vital organs are damaged and can fail.

When heart failure progresses to the point of symptoms, the goal of medical treatment is to slow its progress and prolong the patient's life. Standard treatments involve ACE inhibitors like enalapril to reduce blood pressure, diuretics to reduce fluid retention, and beta blockers to decrease the workload on the heart. More severe cases may require implants or heart surgery.

Doctors have several medications within the ACE inhibitor family to choose from when treating heart failure. When enalapril is prescribed, the daily dose is the same as for high blood pressure but taken in two doses rather than just one. 

• Standard adult dosage of enalapril for heart failure: 5–20 mg taken twice daily

• Maximum adult dosage of enalapril for heart failure: 40 mg daily

Enalapril dosage for asymptomatic left ventricular dysfunction

Like many diseases, heart failure is a progressive disease with clearly identifiable stages. The most common type of heart failure is left ventricular dysfunction, a condition in which the bottom left chamber of the heart does not pump enough blood out of the aorta to the rest of the body. Coronary artery disease and high blood pressure are the most common causes of left ventricular dysfunction. 

In its earliest stage, left ventricular dysfunction has no symptoms but can be diagnosed by echocardiogram (heart ultrasound). Doctors call this Stage B or “silent” heart failure. When doctors treat heart failure at this very early stage, treatment can significantly delay or prevent heart failure from progressing to the symptomatic stage, reducing the risk of future hospitalization or death. 

The standard treatments for Stage B heart failure are beta blockers to reduce the heart’s workload and either ACE inhibitors or angiotensin receptor blockers to lower blood pressure. As with overt heart failure, enalapril doses are taken twice daily, but dosages are cut in half.

• Standard adult dosage of enalapril for asymptomatic left ventricular dysfunction: 2.5–10 mg taken twice daily

Enalapril dosage for children

Enalapril is FDA-approved to treat pediatric hypertension in children 1 month of age and older. Doses are based on body weight. 

Parents can give their child either tablets or liquid. Doses are usually given once daily.

• Standard enalapril dosage for children 6 months of age and older: 0.08 mg/kg–0.58 mg/kg given once daily

• Maximum enalapril dosage for children 6 months of age and older: 40 mg daily

Enalapril dosage restrictions

Liver dysfunction does not require enalapril dosage reductions, but severe kidney disease does. The FDA recommends a lower first dose in people with severe kidney impairment or low sodium (hyponatremia).

• Patients with renal impairment (kidney disease):

  • Mild renal impairment (serum creatinine clearance = 30–89 mL/min): no dosage adjustment required

  • Moderate to severe renal impairment (creatinine clearance ≤30 mL/min), dialysis, or hyponatremia: initial dose of 2.5 mg daily

Enalapril dosage for pets

Veterinarians use enalapril to treat congestive heart failure and certain types of kidney diseases in dogs and cats. They also use it to treat high blood pressure in cats. The drug is safe, and adverse effects are relatively minimal. 

Doses are given once or twice daily, either as tablets or a liquid. The standard dosage for dogs is 0.5 mg per kilogram of body weight given every 12–24 hours. For cats, the standard dosage is 1.25–2.5 mg, given once or twice daily.

How to take enalapril 

Enalapril oral tablets do not involve special instructions for taking doses. The oral solution may require a few extra steps:

• Take enalapril doses as instructed. Doses may change during the course of treatment.

• Do not stop using this medicine without talking to the prescriber.

• Enalapril doses can be taken with food or on an empty stomach.

• How to take enalapril tablets:

  • Tablets are taken once or twice daily.

  • Swallow the tablet whole with a drink of water.

  • Store enalapril tablets at room temperature, protected from moisture.

• How to take enalapril oral solution:

  • Measure the doses with the calibrated oral syringe provided with the medicine. Do not use kitchen measuring tools or tableware.

  • Store enalapril oral solution in a refrigerator. Do not freeze.

  • Enalapril oral solution can be stored at room temperature for up to 60 days. After that, throw away any remaining medicine.

• A pharmacist can prepare an enalapril oral suspension (liquid). Follow the pharmacist’s instructions for giving doses and storing the suspension.

Enalapril dosage FAQs

How long does it take enalapril to work?

According to one study, enalapril starts reducing blood pressure about three hours after a dose is taken.

How long does enalapril stay in your system?

The body changes enalapril into its active form enalaprilat. This active metabolite has a half-life of 11 hours, so it will take more than two days to completely clear a dose from the system.

What happens if I miss a dose of enalapril?

Ask the prescriber what to do if a dose of enalapril is missed. The instructions may vary depending on the practitioner and the condition being treated. Never take extra doses to make up for a missed dose.

How long can you take enalapril?

Enalapril is a long-term and potentially lifelong drug treatment. 

Can you overdose on enalapril?

Yes. Never take more enalapril than prescribed or take it more often than prescribed. An overdose can cause severely low blood pressure (hypotension). Symptoms of hypotension include dizziness, lightheadedness, tiredness, chest pain, shortness of breath, fatigue, weakness, confusion, and fainting. If too much enalapril is taken or you experience symptoms of low blood pressure, get immediate medical care.

What interacts with enalapril?

Enalapril has several significant drug interactions with prescription drugs, over-the-counter medications, and supplements. Make sure the prescribing healthcare provider knows if you’re taking:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) 

• Other drugs that affect the aldosterone-renin-angiotensin system, such as other ACE inhibitors, angiotensin receptor blockers (ARBs), or aliskiren

• Other blood pressure drugs, particularly Entresto (sacubitril/valsartan), are contraindicated for concomitant use with ACE inhibitors

• Drugs that make you pee (diuretics), particularly potassium-sparing diuretics such as spironolactone or amiloride

• Potassium supplements or potassium-containing salt substitutes

• The bipolar drug lithium

• The antibiotic trimethoprim that is found in Bactrim

• The immune suppressants everolimus, tacrolimus, sirolimus, or temsirolimus

• Gold injections (for rheumatoid arthritis)

What happens when you mix enalapril and alcohol?

Alcohol does not directly affect enalapril, but it can raise blood pressure and speed up the heart. People with high blood pressure or heart failure should follow the doctor’s instructions on alcohol use. 

Is it safe to take enalapril during pregnancy?

Enalapril can harm a fetus, particularly in the last two trimesters of pregnancy. Immediately tell the prescriber if you get pregnant or think you’re pregnant. The clinician may need to discontinue enalapril treatment and put you on a different blood pressure medication. 

Is it safe to take enalapril while breastfeeding?

Women should avoid breastfeeding when taking enalapril. The drug and its active metabolite enalaprilat are present in human breast milk and may cause problems in a nursing infant, such as high potassium, low blood pressure, or kidney dysfunction. 

What are the side effects of enalapril?

The most common side effects of enalapril are low blood pressure, dizziness, and fatigue. More serious adverse reactions include severely low blood pressure, high serum potassium levels (hyperkalemia), chest pain, kidney problems, renal failure, severe liver problems, hepatic failure, low white blood cell counts (agranulocytosis or neutropenia), heart attack (myocardial infarction), stroke, and severe drug reactions. To prevent serious problems, the doctor will schedule regular visits and blood tests to monitor blood pressure, renal function, and electrolyte levels. Home blood pressure monitoring and writing down blood pressure readings is always a good idea. Keep all appointments.

Sources

• Angiotensin-converting enzyme inhibitors for use in animals, Merck Veterinary Manual

• Blood pressure lowering efficacy of angiotensin-converting enzyme (ACE) inhibitors for primary hypertension, Cochrane Database of Systematic Reviews

• Effects of enalapril on 24-hour blood pressure in patients with essential hypertension, Current Therapeutic Research

• Enalapril, Plumb’s Drug Handouts

• Epaned enalapril maleate solution prescribing information, DailyMed (NIH National Library of Medicine)

• Hypertension prevalence, awareness, treatment, and control among adults age 18 and older: United States, August 2021–August 2023, Centers for Disease Control and Prevention (CDC)

• Left ventricular failure, StatPearls

• Plumb’s Veterinary Drug Handbook, 7th edition

• Stage B heart failure: management of asymptomatic left ventricular systolic dysfunction, Circulation

• Vasotec drug summary, Prescriber’s Digital Reference (PDR)

• Vasotec enalapril maleate tablet prescribing information, DailyMed (NIH National Library of Medicine)