Enalapril: 7 things you should know
Medically reviewed by Carmen Fookes, BPharm. Last updated on Dec 29, 2019.
1. How it works
- Enalapril may be used in the treatment of high blood pressure or heart failure and works by inhibiting an enzyme called angiotensin-converting enzyme (ACE).
- This enzyme is involved in the production of angiotensin II, a powerful vasoconstrictor (narrows arteries), which also stimulates the release of the hormone aldosterone from the adrenal glands (aldosterone can increase blood pressure). By inhibiting this enzyme, enalapril opens up the arteries (vasodilates) and lowers blood pressure. This also reduces how hard the heart has to work to pump blood around the body, helping to relieve symptoms of heart failure.
- Enalapril belongs to a group of medicines known as angiotensin-converting enzyme (ACE) inhibitors.
- May be used for the treatment of high blood pressure or heart failure.
- Enalapril may also be given to people with evidence of dysfunction of the left ventricle of their heart, but currently without symptoms of heart failure (a condition called left ventricular dysfunction). Trials have shown enalapril reduces the development of heart failure in people with this condition and reduces the incidence of hospitalization.
- In high blood pressure, enalapril reduces both lying down and standing blood pressure without a significant orthostatic effect (this is the drop sometimes seen when going from sitting to standing). However, dehydrated patients may be at higher risk of an orthostatic effect.
- In people with heart failure, enalapril decreases heart size and increases how much blood the heart can pump out. It also increases exercise tolerance, without having much of an effect on heart rate. Enalapril use can decrease the severity of heart failure, rates of hospitalization and symptoms such as shortness of breath and tiredness. Beneficial effects remain apparent with continued dosing.
- Effective alone or in combination with other treatments for high blood pressure.
- Available as oral tablets, a suspension, and in an injectable form.
- Generic enalapril is available.
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- A headache, dizziness, and fatigue are the most common side effects.
- A dry cough which usually resolves on discontinuation of therapy. This side effect is common to all ACE inhibitors.
- Occasionally may cause excessive lowering of blood pressure but the risk is higher in those on diuretic therapy or who are sodium depleted or dehydrated.
- Rarely may cause angioedema of the face, lips, tongue, throat, and extremities. May occur at any time during treatment. Immediate discontinuation is warranted if angioedema is affecting breathing.
- Also rare is the development of blood disorders and liver failure.
- May increase blood potassium levels, the risk is higher in people with diabetes, poor kidney function, and using potassium-sparing diuretics or taking potassium supplements.
- May have less of a blood pressure-lowering effect in patients of African-American descent compared to those without this ethnicity. Also, the incidence of angioedema (skin reaction associated with head and neck swelling) is higher in African-American patients.
- May not be suitable for some people including those with kidney disease, liver disease, a history of blood clots, or electrolyte imbalances.
- Should not be used by women who are pregnant or at risk of pregnancy because it may cause injury or death to the developing fetus.
- Can interact with a number of other medications (including NSAIDs and lithium) - consult your prescribing doctor before taking any other medications including those brought over the counter. People who have diabetes should not take enalapril and aliskiren together.
Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects
- May be taken with or without food.
- Treatments that lower blood pressure, such as enalapril, should always be part of a comprehensive cardiovascular risk reduction plan that also targets, if appropriate, cholesterol lowering, diabetes risk reduction, exercise, weight loss, and smoking cessation.
- Ensure adequate hydration before starting enalapril.
- If you are prescribed enalapril suspension, shake it well before measuring the dose with the dosing syringe provided or a properly calibrated measuring cup. Do not use a kitchen teaspoon. Store the suspension in the refrigerator, do not freeze. Throw away any unused suspension after 60 days.
- Enalapril may make you feel dizzy, especially in the first few weeks of therapy and when going from a sitting or lying down position to standing. Always take your time when standing up. Talk with your doctor if this feeling persists.
- Call emergency services if your throat, face or lips show signs of swelling.
- Report any signs of fever or a sore throat to your doctor who may carry out further tests to ensure it is not neutropenia (a decrease in white blood cells).
- Also call your doctor if you develop chest pain, a change in your heartbeat or muscle contraction or weakness.
- Your doctor should monitor your blood pressure, kidney function and potassium levels regularly.
- For high blood pressure, continue this medication even if you feel well. High blood pressure does not usually have symptoms.
- Do not use salt substitutes or potassium supplements while taking enalapril, unless recommended by your doctor.
- If you also have diabetes, you may need to monitor your blood sugar levels more closely during the first few weeks of enalapril therapy.
- Do not use enalapril if you are pregnant or trying to become pregnant or if you are breastfeeding.
- Limit your alcohol intake while taking enalapril because enalapril can further lower your blood pressure and increase the risk of side effects.
6. Response and Effectiveness
- Peak concentrations of enalapril occur within an hour of oral administration, 15 minutes after IV administration. Enalapril is hydrolyzed to enalaprilat once inside the body; enalaprilat is a more potent inhibitor of angiotensin converting enzyme than enalapril. Peak concentrations of enalaprilat occur within three to four hours after administration of enalapril.
- Blood pressure lowering effects are seen within an hour of oral administration with peak effects achieved by four to six hours. Blood pressure lowering effects are maintained for at least 24 hours, although in some patients these effects may diminish towards the end of the 24 hour period. It may take several weeks before optimal blood pressure lowering effects are achieved. Abrupt withdrawal of enalapril has not resulted in an abrupt increase in blood pressure; however, as with most antihypertensive drugs, it is best to discontinue enalapril slowly.
Medicines that interact with enalapril may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with enalapril. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.
Common medications that may interact with enalapril include:
- allopurinol (may enhance the potential for allergic reactions)
- antipsychotic agents (may enhance the blood pressure-lowering effect)
- gold injections for arthritis
- grass pollen allergen extract
- NSAIDs, such as ibuprofen, diclofenac, and naproxen
- other ACE inhibitors (such as captopril or lisinopril) or ARBs (such as candesartan or irbesartan)
- phosphodiesterase-5-inhibitors, such as sildenafil
- potassium supplements.
Enalapril may also cause blood sugar levels to drop more than expected when taken with diabetes medication, including insulin. Increased blood sugar monitoring may be required.
Note that this list is not all-inclusive and includes only common medications that may interact with enalapril. You should refer to the prescribing information for enalapril for a complete list of interactions.
Enalapril. Revised 08/2019. Drugs.com. https://www.drugs.com/ppa/enalapril.html
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use enalapril only for the indication prescribed.
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- Drug class: Angiotensin Converting Enzyme Inhibitors
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