Lisinopril vs. Losartan: The Short Answer
Lisinopril and losartan are two of the most prescribed blood pressure medicines in the country. For most people they lower blood pressure about equally well, both are taken once a day in most cases, and both are inexpensive generics.
The real differences are in side effects and in a handful of specific situations. Lisinopril is an ACE inhibitor. Losartan is an angiotensin receptor blocker, or ARB. If lisinopril gives you a nagging dry cough, losartan is usually the next step. If you have no side effects on either, there is rarely a reason to switch.
How Each Drug Works
Both medicines act on the same hormone chain, called the renin-angiotensin system, which helps your body control blood pressure and fluid balance. The key hormone in that chain is angiotensin II, which tightens blood vessels and tells the kidneys to hold on to salt and water.
- Lisinopril blocks the enzyme (ACE) that makes angiotensin II, so less of the hormone is produced.
- Losartan lets the hormone be made but blocks the receptor it needs to act on.
The end result is similar: blood vessels relax and blood pressure falls. The difference in mechanism explains the difference in side effects. The ACE enzyme also breaks down a substance called bradykinin, so blocking ACE lets bradykinin build up. That buildup is behind the classic ACE inhibitor cough and part of the risk of a rare swelling reaction. ARBs leave bradykinin alone.
Side Effects: Where They Really Differ
The ACE inhibitor cough
A dry, tickly cough that will not go away is the best-known side effect of lisinopril and the most common reason people switch. It can start within weeks or appear months into treatment, and it is easy to mistake for allergies or a lingering cold. It usually fades within a few weeks of stopping the drug, although it can take longer. ARBs such as losartan rarely cause it. The Cleveland Clinic overview of ACE inhibitors describes this and other side effects in plain language.
Angioedema
Rarely, ACE inhibitors cause angioedema: sudden swelling of the lips, tongue, face, or throat. It is more common in Black patients and can happen even after years of uneventful use. It is an emergency if it affects breathing or swallowing. ARBs carry a much lower risk, but anyone who has had angioedema on an ACE inhibitor needs an individual discussion before trying an ARB.
Side effects they share
- Dizziness, especially when standing quickly in the first weeks or after a dose increase
- Higher potassium levels, which is why salt substitutes made with potassium chloride and potassium supplements should be cleared with your doctor first
- A small rise in creatinine on kidney labs when the drug starts, which is often expected and acceptable
The MedlinePlus guides to lisinopril and losartan list the full side-effect profiles.
Kidney, Heart, and Diabetes Benefits
Both drug classes protect the kidneys in people who leak protein into the urine, which makes them preferred choices for people with chronic kidney disease or diabetes. Their FDA approvals differ a little:
- Lisinopril is approved for high blood pressure, heart failure, and improving survival after a heart attack.
- Losartan is approved for high blood pressure, kidney disease in people with type 2 diabetes, and lowering stroke risk in people with high blood pressure and a thickened heart muscle.
In everyday practice, doctors treat the two classes as close substitutes for most of these uses. Losartan has one small bonus: it modestly lowers uric acid, which can be helpful for people who also have gout.
Who Should Not Take Either One
- Pregnancy. Both carry a boxed warning because they can harm a developing baby, especially later in pregnancy. Stop and call us right away if you become pregnant, and tell us if you are planning a pregnancy.
- Both together. Combining an ACE inhibitor with an ARB raises the risk of kidney injury and dangerously high potassium without adding real benefit for most people.
- A history of angioedema on an ACE inhibitor rules out lisinopril.
Be careful with regular use of anti-inflammatory pain relievers such as ibuprofen and naproxen while on either drug. Together with a diuretic, that combination can strain the kidneys, particularly when you are dehydrated.
How Your Doctor Chooses
Current guidelines list ACE inhibitors, ARBs, thiazide diuretics, and calcium channel blockers as reasonable first choices for high blood pressure. Our article on blood pressure medication classes covers the others. Between lisinopril and losartan, the decision usually comes down to a few questions:
- Have you had a cough or swelling on an ACE inhibitor? If so, an ARB is the usual choice.
- Do you have kidney disease, diabetes with protein in the urine, or heart failure? Either class is a strong fit.
- Do you need more than one medicine? Both come in combination pills with hydrochlorothiazide, which can simplify a routine.
- What does your insurance cover? Both are low-cost generics, so cost rarely decides it.
Monitoring after you start
We typically check a basic blood panel for potassium and kidney function a few weeks after starting either medicine or changing the dose. Tracking your numbers at home helps us adjust faster; our guide to home blood pressure monitoring shows how to get accurate readings.
Florida Considerations
St. Petersburg summers make dehydration easy, and dehydration plus a blood pressure medicine can mean lightheadedness or extra strain on the kidneys. If you are sick with vomiting or diarrhea and cannot keep fluids down, call us about whether to pause your dose until you recover. During hurricane season, keep at least a two-week supply on hand. Never stop either medicine on your own because your readings look good; that usually means it is working.
When to See Your Doctor
- A dry cough that started after beginning lisinopril and will not go away
- Dizziness or fainting, especially when you stand up
- Swelling of the lips, tongue, face, or throat (call 911 if breathing or swallowing is affected)
- Home readings that stay above your target for more than a week or two
- A positive pregnancy test or plans to become pregnant
- Muscle weakness or an irregular heartbeat, which can signal high potassium
Wondering whether your blood pressure medicine is the right fit? Schedule a visit and we will review your readings, labs, and side effects together.
