Enalapril

High Blood Pressure

Enalapril is used to treat hypertension (high blood pressure). Lowering high blood pressure helps prevent serious health issues, including:

• Strokes
• Heart attacks
• Kidney problems

Heart Failure

This medication is prescribed to treat heart failure, a condition where the heart is unable to pump enough blood to meet the body's needs. It helps improve symptoms and may reduce the need for hospitalization.

Left Ventricular Dysfunction

Enalapril is also used for patients with left ventricular dysfunction. This is a condition where the heart's main pumping chamber is weakened, even if the person does not yet feel symptoms of heart failure. In these cases, the drug is used to help prevent heart failure from developing or worsening.

Enalapril may be used alone or along with other medications to manage these conditions.

Mechanism of Action

Enalapril is an angiotensin-converting enzyme (ACE) inhibitor. It works by interfering with the body's production of a chemical called angiotensin II. This chemical normally causes blood vessels to tighten and narrow, which increases blood pressure and makes the heart work harder.

Effects on the Body

By blocking the production of angiotensin II, enalapril helps the body achieve the following:

• Blood Vessel Relaxation: The blood vessels widen and relax, allowing blood to flow through them more easily.
• Lower Blood Pressure: As the vessels relax, the pressure against the artery walls decreases.
• Reduced Heart Workload: Because the blood vessels are wider, the heart does not have to pump as forcefully to move blood throughout the body.

In patients with heart failure, these actions help the heart pump more efficiently and improve the delivery of oxygen and blood to the heart muscle and other organs.

Common Side Effects

Some people may experience mild side effects while taking enalapril. These often include:

• Dizziness or lightheadedness, particularly when rising from a sitting or lying position
• A persistent, dry, hacking cough
• Headache
• Fatigue or unusual tiredness
• Nausea or diarrhea
• Mild skin rash

Serious Side Effects

Seek medical attention immediately if you notice any of the following serious symptoms:

• Swelling of the face, throat, tongue, lips, eyes, hands, or feet
• Difficulty breathing or swallowing
• Hoarseness
• Fainting
• Yellowing of the skin or eyes
• Signs of infection, such as fever, chills, and persistent sore throat
• Chest pain
• Severe stomach pain

Fetal Toxicity

Enalapril can cause injury and death to a developing fetus. When pregnancy is detected, this medication should be discontinued as soon as possible. Exposure to ACE inhibitors during the second and third trimesters is associated with serious fetal risks, including kidney failure and skull deformities.

Angioedema and Allergic Reactions

Serious allergic reactions, including angioedema (swelling of the face, lips, tongue, and throat), can occur at any time during treatment. This condition can be life-threatening if it obstructs the airway. The risk of angioedema may be higher in Black patients and those with a history of previous angioedema.

Low Blood Pressure (Hypotension)

Enalapril can cause excessively low blood pressure, especially after the initial dose. This risk is increased in patients who are dehydrated, on a low-salt diet, receiving dialysis, or taking other diuretics (water pills). Severe hypotension can lead to fainting or impaired kidney function.

Kidney and Liver Function

This medication may cause changes in kidney function, particularly in individuals with pre-existing kidney disease, severe heart failure, or narrowing of the arteries to the kidneys. In rare cases, enalapril has been linked to a syndrome that begins with jaundice (yellowing of the skin or eyes) and can progress to severe liver damage.

Potassium and Blood Monitoring

• Hyperkalemia: Enalapril may cause high levels of potassium in the blood. This risk is higher for patients with diabetes, kidney impairment, or those using potassium supplements.
• Neutropenia: In rare instances, a significant decrease in white blood cells may occur, which can increase the risk of infection. This is more common in patients with kidney problems or autoimmune diseases.

Contraindications

Enalapril should not be used by individuals who have a history of angioedema related to previous ACE inhibitor treatment or those with hereditary or idiopathic angioedema. It is also contraindicated for use with aliskiren in patients with diabetes. A 36-hour waiting period is required when switching between enalapril and medications containing sacubitril.

Persistent Cough

A dry, nonproductive cough may develop during treatment. This cough typically resolves once the medication is discontinued.

Pregnancy

Enalapril is an ACE inhibitor that can cause significant injury and even death to a developing fetus. The risk is particularly high if the medication is taken during the second and third trimesters of pregnancy. Potential complications for the fetus or newborn include:

• Reduced kidney function or kidney failure
• Low blood pressure (hypotension)
• Underdevelopment of the skull
• Decreased amniotic fluid (oligohydramnios)
• Death

If you are planning to become pregnant or discover you are pregnant while taking enalapril, contact your doctor immediately. In most cases, the medication must be stopped as soon as possible to protect the fetus. Your healthcare provider can discuss alternative treatments for managing blood pressure or heart conditions during pregnancy.

Breastfeeding

Enalapril and its active metabolite are excreted into human breast milk in very small amounts. Because the safety of these trace amounts for a nursing infant has not been fully established, caution is advised. Decisions regarding breastfeeding while taking enalapril should be made in consultation with a healthcare professional, considering the necessity of the drug for the mother and the potential impact on the child.

Available Forms

Enalapril is primarily prescribed in the following forms:

• Oral Tablets: These are taken by mouth and are available in multiple strengths to allow for precise dosing.
• Oral Solution: This liquid form is used for patients who have difficulty swallowing tablets or when specific dose adjustments are required.
• Intravenous Injection: A form of the medication called enalaprilat is available as an injection. This is typically administered by healthcare providers in a hospital or clinical setting.

FDA Approval and Indications

Enalapril was first approved by the U.S. Food and Drug Administration (FDA) in 1985. It is currently approved for the following indications:

• Hypertension: To lower high blood pressure in adults and children at least one month of age.
• Heart Failure: To manage symptomatic heart failure, typically used alongside other treatments like diuretics.
• Left Ventricular Dysfunction: To reduce the risk of developing heart failure in patients who have a weakened left ventricle but do not yet show symptoms.

Boxed Warning

The FDA requires a boxed warning for enalapril due to the risk of fetal toxicity. Medications that act on the renin-angiotensin system, such as enalapril, can cause serious injury or death to a developing fetus if taken during the second or third trimesters of pregnancy. Healthcare providers advise discontinuing the medication immediately if pregnancy is detected.

Safety Communications and Contraindications

The FDA has issued specific safety communications and contraindications regarding the use of enalapril with other substances:

• Aliskiren: The use of enalapril in combination with aliskiren is contraindicated in patients with diabetes or kidney impairment because it increases the risk of kidney failure, excessively low blood pressure (hypotension), and high potassium levels (hyperkalemia).
• Neprilysin Inhibitors: Enalapril must not be taken within 36 hours of taking a neprilysin inhibitor (such as sacubitril) due to a significantly increased risk of angioedema, which is a potentially life-threatening swelling of the face, lips, or throat.
• History of Angioedema: It is contraindicated in patients with a history of angioedema related to previous treatment with an ACE inhibitor.

Generic Availability

Enalapril is the generic version of the brand-name drug Vasotec. Generic medications are required to have the same active ingredients, strength, and effectiveness as brand-name drugs but are typically sold at a much lower price.

Factors Influencing Cost

Several factors can influence the total price of enalapril:

• Formulation: Enalapril is available as oral tablets and as an oral solution. The liquid version may be more expensive than the tablet form.
• Dosage and Quantity: Higher strengths or larger quantities per refill may affect the price.
• Pharmacy Choice: Prices can vary between retail pharmacies, mail-order services, and hospital pharmacies.

Insurance and Financial Assistance

Most commercial insurance plans and government programs like Medicare and Medicaid cover generic enalapril. Because it is a common generic medication, it is often placed in the lowest cost-sharing tier of insurance formularies. For those without insurance, many pharmacies offer generic discount programs that may reduce the cost to a fixed monthly rate. Patient assistance programs may also be available for specific formulations of the drug.