How lisinopril works in the body

Imagine a narrow two-lane road. Not a lot of space for cars there, right? Probably prone to real traffic. Now imagine someone comes through and builds an eight-lane highway. That’s how lisinopril works but instead of roads, it’s your blood vessels. Lisinopril and other ACE inhibitors work by relaxing your blood vessels and making them wider, which lowers the pressure of blood in those vessels (aka your blood pressure). 

High blood pressure is an interesting creature because even though 45% percent of adults in the United States have this condition, one in three has no idea they have it (Ostchega, 2020; Wall, 2014).  If it doesn’t bug you enough to get checked out, what’s the big deal? Well, high blood pressure alone might not be a bother, but it can do real damage all over your body. In fact, it’s responsible for half of all strokes and heart attacks—and one in every six deaths around the world (Arima, 2011). 

What causes high blood pressure? A lot of things can contribute but some of the main ones include: a family history of high blood pressure, obesity, increasing age, underlying health conditions like diabetes, cigarette smoking, and an unhealthy diet (Oparil, 2018). 

When it comes to getting your blood pressure down, there are a lot of good options out there. Picking one that’s right for you is usually a function of how your body responds to a medication. For example, ACE inhibitors like lisinopril work by blocking an enzyme called ACE. This enzyme produces a hormone called angiotensin II, which helps regulate blood pressure by causing blood vessels to constrict. By blocking the production of angiotensin II, lisinopril keeps blood vessels open and relaxed, in turn lowering blood pressure (Lopez, 2020). 

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What are ACE inhibitors actually doing in the body to lower your blood pressure? 

Back to our traffic metaphor: Your blood vessels are like roads that carry your blood to different areas of your body. When you have high blood pressure, those roads are small and narrow like a two-lane highway and one of the things that keep those roads small is an enzyme called angiotensin II. ACE inhibitors work by blocking that enzyme, allowing the roads (your blood vessels) to widen (think 8-lane superhighway) so there’s no more traffic (Fountain, 2020). 

And while it may not be true on your morning commute, sometimes a little traffic in your blood vessels is a good thing. Maintaining blood pressure at a certain level is important for making sure that your blood goes everywhere it needs to go, like up to your brain while you’re standing. The problems arise when that pressure is too high. 

All of that traffic in your blood vessels can damage them, leading to problems both within the blood vessels themselves (atherosclerosis) and within your organs (like the kidneys and heart), so it’s important to get treatment. 

Along with drug therapy, lifestyle changes are recommended to keep high blood pressure at bay. Eating a healthy diet, exercising regularly, cutting out smoking, and managing stress are just a few positive steps you can take towards keeping your blood pressure within a normal range. If these steps don’t do the job alone, your healthcare provider may recommend one or more medications to treat it (DailyMed, 2017).

What else is lisinopril used for?

In addition to its use for the treatment of high blood pressure, lisinopril can also be used in the treatment of other conditions, including (FDA, 2014):

• Heart failure: When high blood pressure is left untreated, blood vessels thicken and become less flexible, reducing the amount of room there is for blood to flow. This puts extra stress on your heart, which increases the risk for more serious issues down the road like heart failure and stroke. By keeping blood pressure levels low, lisinopril makes it easier on the heart to pump and helps improve survival rates in patients with heart failure (Lopez, 2020). 

• Heart attacks: ACE inhibitors are also used to improve survival rates in patients after a myocardial infarction, or heart attack. When given to a stable patient within 24 hours of a myocardial infarction, lisinopril reduces the risk of death and may help prevent future heart attacks (FDA, 2014).

How to take lisinopril—and who shouldn’t take it

Lisinopril is an oral tablet that’s usually taken once per day, depending on what condition it’s being used for. The medication is available in doses of 2.5 mg, 5 mg, 10 mg, 20 mg, 30 mg, and 40 mg (FDA, n.d.). While this drug has been deemed safe for adults and children ages 6 and up to use for hypertension, always talk to a health provider beforehand as lisinopril carries risks for certain side effects, which we’ll look at in the next section. 

Lisinopril can be dangerous when mixed with other medications or for people with underlying health conditions. Pregnant women should not use ACE inhibitors as these drugs are toxic to a growing fetus (DailyMed, 2017). The safety of lisinopril hasn’t been determined yet for women who are nursing. Children under age 6 should not be given lisinopril. If you have or have ever had any of the conditions below, also avoid taking this drug (FDA, 2014):

• Angioedema

• Kidney disease

• High blood potassium

• Low blood pressure 

• Liver disease

• Allergies to ACE inhibitors

Common side effects you may experience using lisinopril include headaches, dry cough, chest pain, dizziness, fainting, and hypotension (DailyMed, 2017). In fact, studies have found that roughly 20% of individuals stop using ACE inhibitors because of side effects—chronic cough being the main grievance (Yilmaz, 2019). If you are having side effects, consult with a healthcare provider before stopping any medication as they may be able to adjust your dose or recommend another drug. Lisinopril also carries risks for more serious reactions, including hyperkalemia, worsening kidney function, and severe allergic reactions (FDA, 2014).

Lisinopril is frequently prescribed as a combination drug with hydrochlorothiazide (brand name Zestoretic) (FDA, n.d.). Hydrochlorothiazide is a diuretic, aka “water pill,” which aids in lowering blood pressure by signaling the body to expel extra fluid. Side effects seen from taking this drug have included: cough, dizziness, fatigue, hypotension, gastrointestinal problems, muscle cramps, rash, and weakness (DailyMed, 2017).

Because lisinopril is often taken alongside other blood pressure medications, it’s important to know which ones it could interact with. Talk to a healthcare provider before taking lisinopril, especially if you are using any of the medications listed below. This does not include all the drugs lisinopril could react with, but here are some important ones to be aware of (FDA, 2014):

• Diuretics (water pills): Patients with hypertension may also be prescribed diuretics, which signal the body to release excess salt and water from the body. Taking lisinopril with diuretics can cause hypotension and hyperkalemia. 

• Antidiabetics: Insulin and oral hypoglycemic medications are examples of antidiabetic drugs used to manage blood sugar levels. Lisinopril may increase the risk of low blood sugar in people taking antidiabetics at the same time.

• Nonsteroidal anti-inflammatories (NSAIDs): NSAIDs can be dangerous when mixed with lisinopril, causing harm to the kidneys and even putting some patients who live with kidney disease into renal failure. 

• Aliskiren: Aliskiren is another type of blood pressure medication called a renin inhibitor. Combining ACE inhibitors with renin inhibitors has the potential for serious problems, such as hypotension, hyperkalemia, and kidney failure. 

• Lithium: Used to alleviate symptoms of bipolar disorder, lithium can reach toxic levels in the body if taken at the same time as lisinopril.

• Gold: Gold injections are sometimes used as therapy for patients living with joint conditions like rheumatoid arthritis (UpToDate, 2019). Interactions with lisinopril are rare, but using the two together could cause symptoms such as hypotension, facial flushing, nausea, and vomiting.

Avoid alcohol while using lisinopril as it makes certain side effects, like dizziness and fainting, worse. Potassium supplements, as well as salt substitutes containing potassium, should also be avoided on ACE inhibitors.

Some people with elevated blood pressure or who are in the early stages of hypertension may not need medication for it. If you suspect you have hypertension, talk to a healthcare professional about getting tested. Even if you don’t have symptoms, get your blood pressure checked regularly—especially if you have any risk factors for high blood pressure or heart disease. Part of the reason why hypertension is so deadly (and why it’s referred to as a “silent killer”) is because many people don’t experience any symptoms at all (Oparil, 2018).

There are also lots of things you can do on your own to reduce your risk for developing hypertension, or to prevent it from worsening. Keep yourself at a healthy weight by staying physically active and eating healthy. Incorporate more fresh fruits and veggies into your diet, and limit your salt and sugar intake. Other recommendations include cutting down on how much alcohol you drink, getting enough sleep, and managing stress (CDC, 2020). 

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Current version

January 06, 2021

Written by

Anna Brooks

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.