Losartan

Medically reviewed by Victor Nguyen, PharmD, MBA on April 17, 2023
Written by Sarah Lewis, PharmD

Specifically, the Food and Drug Administration (FDA) has approved losartan oral tablet to:

• treat high blood pressure in adults and certain children
• lower the risk of stroke in certain adults with high blood pressure
• treat diabetic kidney disease in certain adults with type 2 diabetes

This article describes losartan oral tablet’s uses and dosage, ways to save on cost, and more. Below you’ll find coupon options for losartan.

Boxed warning: Risk of harm if taken during pregnancy

Losartan has a boxed warning about the risk of fetal harm or pregnancy loss if the drug is taken during pregnancy. Boxed warnings are serious warnings from the FDA.

For details, see the “Warnings for losartan” section below.

Losartan may cause mild or serious side effects (also known as adverse effects). More common mild side effects of losartan oral tablet and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age and overall health and any other medications you take.

To learn more about losartan oral tablet’s side effects, see this article or ask your doctor or pharmacist. You can also read the prescribing information for losartan oral tablet.

Mild side effects

More common mild side effects reported with losartan oral tablet are listed below.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Losartan oral tablet’s mild side effects include:

• back pain
• a cough
• dizziness
• fatigue (low energy)
• headache, including migraine
• joint or muscle aches
• nausea or vomiting
• stuffy nose
• upper respiratory infection, such as a cold
• mild allergic reaction*

* For details about this side effect, see the “Warnings for losartan” section below.

Serious side effects

Serious side effects of losartan oral tablet are listed below. With many drugs, serious side effects are possible but not common.

If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

Losartan oral tablet’s serious side effects include:

• depression
• fainting
• heart rhythm problems
• high potassium levels in the blood
• low red blood cell levels
• problems with kidney function
• sleep disorders
• very low blood pressure
• boxed warning: risk of harm if taken during pregnancy*
• severe allergic reaction*

* For details about this side effect, see the “Warnings for losartan” section below.

The Food and Drug Administration (FDA) approves prescription drugs such as losartan for certain conditions. Approved uses for losartan oral tablet are described below.

Use for high blood pressure

Doctors may prescribe losartan oral tablet for treating high blood pressure. It’s used for this purpose in adults and children 7 years of age and older. It’s usually prescribed as a long-term treatment.

With high blood pressure, people often don’t have noticeable symptoms. But having high blood pressure increases the risk of serious health problems, including heart attack and stroke.

Losartan is sometimes prescribed together with other blood pressure-lowering drugs for high blood pressure.

Use for lowering the risk of stroke

Doctors may prescribe losartan oral tablet to help lower the risk of stroke. It’s used for this purpose in adults with high blood pressure and the heart condition left ventricular hypertrophy (LVH). It’s usually prescribed as a long-term treatment.

With LVH, the lower left heart chamber can’t pump oxygenated blood out to the rest of the body as well as it should. Having LVH is often a sign of long-standing high blood pressure. It also increases the risk of having a stroke.

It’s important to note that your race may affect how your body responds to losartan oral tablet treatment for lowering the risk of stroke. For more information, talk with your doctor. They can determine whether losartan is right for you.

Use for diabetic nephropathy

Doctors may prescribe losartan oral tablet for treating diabetic nephropathy. It’s used for this purpose in adults with a high creatinine level, protein in their urine, and a history of high blood pressure. It’s usually prescribed as a long-term treatment.

With diabetic nephropathy, high blood sugar caused by diabetes damages the kidneys. This causes the kidneys to have problems working as well as they should. Losartan oral tablet can slow down this kidney damage.

The dosage of losartan oral tablet your doctor prescribes may vary based on your condition and certain other factors. Talk with your doctor about the dosage you should take.

Taking losartan

Losartan oral tablet is taken by mouth.

Your doctor will talk with you about how to take losartan oral tablet. They’ll explain how much to take and how often. Always follow your doctor’s recommendation.

Losartan oral tablet can be taken with or without food.

See the “Common questions about losartan” section for information on missed doses and the best time to take this drug.

Overdose of losartan

You should not take more losartan than your doctor prescribes. For some drugs, doing so may lead to serious side effects or overdose.

If you think you’ve taken too much losartan, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Below you’ll find answers to a few commonly asked questions about losartan oral tablet.

How does losartan compare with other similar drugs, such as lisinopril or valsartan?

Losartan oral tablet is an angiotensin II receptor blocker (ARB) drug. There are several other ARB drugs, including olmesartan (Benicar), telmisartan (Micardis), and valsartan (Diovan). ARBs tend to have similar side effects and warnings.

A group of drugs called angiotensin converting enzyme (ACE) inhibitors is related to ARB drugs. Lisinopril (Prinivil, Zestril) is an example. ACE inhibitors have similar uses and benefits to ARB drugs. Because ACE inhibitors are related to ARBs, some of their side effects and warnings are similar.

Another group of drugs that has similar uses and benefits is calcium channel blockers. Amlodipine (Norvasc) is an example. But these drugs work in a different way than ARBs and ACE inhibitors. So, their side effects and warnings can be different.

To learn more about drugs similar to losartan oral tablet, talk with your doctor or pharmacist.

Will I experience certain side effects when stopping losartan?

No, side effects when stopping losartan oral tablet aren’t likely. Side effects from stopping the drug weren’t reported in studies.

If you want to stop taking losartan oral tablet, talk with your doctor. They may be able to suggest other options. Do not stop taking losartan before talking with your doctor. It can be dangerous to leave high blood pressure untreated.

Is losartan a diuretic?

No, losartan oral tablet isn’t a diuretic. It’s an angiotensin II receptor blocker (ARB) drug. It works to relax blood vessels, which lowers blood pressure. It also helps protect the kidneys and heart.

Diuretics (commonly called water pills) help the body get rid of extra fluids. This can reduce swelling and lower blood pressure.

To learn more about diuretics, talk with your doctor or pharmacist.

How does losartan work? And how long does it take to start working?

Losartan oral tablet works by blocking the hormone angiotensin II from binding to its receptors (binding sites on cells). Angiotensin II makes your blood vessels tighten and narrow. This increases the pressure inside your blood vessels.

When losartan oral tablet blocks the receptor, angiotensin II can’t bind to it. This stops angiotensin II from making your blood vessels narrow, and can lower your blood pressure.

Losartan oral tablet starts working within 24 hours. But it can take up to a week to see a consistent effect on your blood pressure. Sometimes, it can take 3 to 6 weeks to see the drug’s maximum effect on blood pressure.

For more questions about what to expect with losartan oral tablet, talk with your doctor or pharmacist.

Is there a best time of day to take losartan? What should I do if I miss a dose?

No, you can take losartan oral tablet at any time of day, unless your doctor recommends a certain time.  But it’s best to take it at the same time each day. This helps keep a consistent level of drug in your body. Always follow your doctor’s instructions.

If you miss a dose of losartan oral tablet, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose. Take the next dose at the usual time. Do not double up and take two doses together. This could cause serious side effects.

If you need help deciding whether or not to take a missed dose, call your doctor or pharmacist.

Can losartan tablets be crushed, split, or chewed?

Possibly. The drugmaker doesn’t give any advice about crushing, splitting, or chewing losartan oral tablet. Ask your pharmacist or your doctor to be sure.

If you’re having trouble swallowing tablets, talk with your doctor or pharmacist.

For some medications, certain things may affect how the drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take losartan, ask your doctor to check for possible interactions. They can check for interactions these items may cause with losartan. Be sure to tell them about any of the following you take or use:

• prescription medications
• over-the-counter medications
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for losartan” section below.

Losartan should not be taken or should be taken cautiously by certain people. Precautions for taking this drug are described below.

Boxed warning: Risk of harm if taken during pregnancy

Losartan has a boxed warning about the risk of fetal harm or pregnancy loss, if the drug’s taken during pregnancy. Boxed warnings are serious warnings from the Food and Drug Administration (FDA).

Taking losartan oral tablet while you’re pregnant can cause harm or death to the fetus. Tell your doctor immediately and stop taking losartan oral tablet as soon as possible if you become pregnant.

To learn more, talk with your doctor or pharmacist.

Other warnings

Losartan could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether losartan oral tablet is a safe option for you.

Tell your doctor about your overall health and any past health conditions before you take losartan oral tablet. Health conditions and other factors you and your doctor should discuss include:

• kidney problems
• liver problems
• low blood pressure
• medications you take, including high dose diuretic drugs and aliskiren for diabetes treatment

Allergic reaction

Losartan can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to losartan or any of its ingredients, your doctor will likely not prescribe losartan. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to losartan, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Information about losartan and pregnancy and breastfeeding is described below.

Losartan and pregnancy

Losartan oral tablet should not be taken during pregnancy. In fact, the drug has a boxed warning about the risk of fetal harm pregnancy loss if it’s taken during pregnancy. This is a serious warning from the Food and Drug Administration (FDA).

If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. Your doctor may suggest birth control options to use during treatment with losartan.

Losartan and breastfeeding

Losartan oral tablet should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with losartan.

You may be able to save money on your prescription for losartan oral tablet by using our Perks discount coupons. These can be found at the end of this article.

If you have questions about how to pay for losartan, talk with your doctor or pharmacist. You can also learn more about the cost of losartan in this article.

Note: Optum Perks coupons cannot be used with insurance copays or benefits.

This article describes losartan oral tablet’s uses and dosage, ways to save on cost, and more. Let your doctor know if you have questions about losartan or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Will I gain weight while taking losartan?
• Do I have any factors or conditions that could make losartan oral tablet unsafe for me?
• How does losartan oral tablet compare to other drugs that could treat my condition?

• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
• Losartan potassium- losartan potassium tablet. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/c43e9dc6-2c8a-47d7-b40d-eb55dfe11a51/spl-doc

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.