What is losartan used for?

In this article:

• Uses
• Uses
• How it works
• How long it takes
• How it's taken
• Side effects
• Contraindications
• Alternatives
• FAQs

In this article

• Uses
• Uses
• How it works
• How long it takes
• How it's taken
• Side effects
• Contraindications
• Alternatives
• FAQs

Losartan (losartan potassium) is a prescription medication primarily used to treat high blood pressure. It is also FDA approved to reduce the risk of stroke in certain people with high blood pressure and left ventricular hypertrophy, and to treat diabetic nephropathy (kidney disease resulting from diabetes) in patients with high blood pressure and Type 2 diabetes. It may also be prescribed off-label for other conditions.

Losartan uses at a glance
Use	FDA-approved use?	Who it may be prescribed for
High blood pressure	Yes	Adults and children 6 years and older
Reducing the risk of stroke	Yes	Certain patients with hypertension and LVH
Diabetic nephropathy	Yes	Certain patients with Type 2 diabetes, hypertension, proteinuria, and elevated serum creatinine
Heart failure	Off-label use	Certain patients, when clinically appropriate

What is losartan used for?

Losartan is used for several conditions. Losartan can be used alone or with other medications. Many patients require more than one drug to achieve their treatment goals, such as lowering high blood pressure. The healthcare provider  will also usually recommend other measures as needed, such as diet and exercise, smoking cessation, and the management of other conditions like diabetes and high cholesterol.

Hypertension (high blood pressure)

Losartan can be used to treat hypertension in adults and children aged 6 years and older. Lowering blood pressure reduces the risk of heart attacks and strokes.

When looking at a blood pressure reading, systolic is the top number, and diastolic is the bottom number. For reference, according to the American Heart Association, the blood pressure ranges (measured in mm Hg) include:

• Normal: Systolic less than 120 and diastolic less than 80.
• Elevated: Systolic of 120-129 and diastolic less than 80.
• Hypertension Stage 1: Systolic 130-139 or diastolic 80-89.
• Hypertension Stage 2: Systolic 140 or higher or diastolic 90 or higher.
• Severe hypertension: Systolic pressure higher than 180 and/or diastolic pressure higher than 120. Patients in this range who do not have symptoms should wait at least one minute, then check again. If blood pressure is still in this range and there are no symptoms, they should call their healthcare provider for medical advice.
• Hypertensive emergency: Systolic pressure higher than 180 and/or diastolic pressure higher than 120 with symptoms, such as chest or back pain, shortness of breath, numbness, weakness, vision changes, or trouble speaking should call 911 for emergency medical attention.

Prevention of stroke in patients with left ventricular hypertrophy

Losartan can be used to lower the risk of stroke in people who have both hypertension and left ventricular hypertrophy (LVH).

This benefit may not apply to African American patients. A clinical trial called the LIFE study found that Black people with hypertension and LVH who took a beta blocker medicine called atenolol had a lower risk of stroke, heart attack, or cardiovascular death than those who took losartan.

Treatment of diabetic nephropathy

Losartan can be used to treat diabetic nephropathy (with increased serum creatinine and proteinuria) in patients with Type 2 diabetes and a history of high blood pressure. Losartan can slow the progression of kidney disease.

Treatment of heart failure

Losartan can be used off-label for the treatment of heart failure with reduced ejection fraction (HFrEF). Off-label prescribing is when a drug is prescribed for a purpose that is not approved by the U.S. Food and Drug Administration (FDA). People with HFrEF are typically prescribed four types of drugs: a beta blocker (such as metoprolol), a mineralocorticoid receptor antagonist (such as spironolactone), an SGLT2 inhibitor (such as Jardiance), and an angiotensin receptor-neprilysin inhibitor (ARNI) such as Entresto (sacubitril/valsartan). Sometimes, instead of an ARNI, healthcare providers will prescribe an ACE inhibitor (such as lisinopril) or an ARB (such as losartan). In addition, other drugs may be prescribed, such as diuretics (water pills) or digoxin.

How does losartan work?

Losartan is a generic prescription drug that’s part of a drug class called angiotensin II receptor blockers, or ARBs. ARBs work by preventing a substance called angiotensin II from binding to its receptor. Angiotensin II causes blood vessels to narrow and blood pressure to increase when it binds to its receptors. By blocking angiotensin II from binding to its receptors, losartan helps lower blood pressure.

The brand name of losartan is called Cozaar. Losartan can also be found as an ingredient in the drug Hyzaar, which contains two ingredients: losartan and hydrochlorothiazide. This article will focus on the single-ingredient medication losartan.

How long does losartan take to work?

Losartan works relatively quickly, with many patients seeing effects within the first week of treatment. However, some studies show that the maximal effect may take up to six weeks of treatment.

How is losartan taken?

Losartan is available as an oral tablet that can be taken with or without food. You can take losartan at any time of day that is convenient for you, but it is best to take it at about the same time each day to maintain consistent levels in the body. Using a medicine organizer, reminder app, or alarm can help you remember to take your medication every day.

Losartan is available in 25 mg, 50 mg, and 100 mg tablets. The exact dosage varies by indication. See the examples below, and always follow your healthcare provider’s guidance.

Hypertension

The usual starting dose for adults with high blood pressure is 50 mg daily. If this dose is not enough to control blood pressure, the healthcare provider may increase it to 100 mg daily (either 50 mg twice daily or 100 mg once daily).

For children and adolescents aged six to 17 years, the dosage is based on weight, with a maximum starting dose of 50 mg daily and a maximum maintenance dose of 100 mg daily.

Prevention of stroke in adults with hypertension and LVH

The healthcare provider will generally start the patient on 50 mg once daily. If further blood pressure reduction is needed, a diuretic (often referred to as a “water pill”) called hydrochlorothiazide (HCTZ) may be added at 12.5 mg daily, and/or the losartan dose may be increased to 100 mg daily. If further blood pressure control is needed, the HCTZ dose may be increased to 25 mg daily.

Diabetic nephropathy

An initial dose of 50 mg once daily will be used. The healthcare provider may increase the dose to 100 mg daily if needed, based on blood pressure response.

Heart failure

The dosage for heart failure, which is an off-label treatment, will start at 25 to 50 mg once daily. The dose may be increased as needed, from 50 to 150 mg per day. Losartan may be used along with a beta blocker, a mineralocorticoid receptor antagonist, and an SGLT2 inhibitor.

Note: The maximum dose of losartan for other uses is 100 mg; the 150 mg dose is used only in heart failure patients when needed.

Follow your healthcare provider’s recommendations for checking blood pressure at home, as well as lab tests. Your provider may also recommend other measures, such as a low-salt diet and increased exercise, that can help lower your blood pressure.

What are the side effects of losartan?

Like any drug, losartan can cause side effects. Before taking losartan, discuss possible side effects with your healthcare provider. Common side effects may include:

• Colds (upper respiratory infection)
• Stuffy nose
• Dizziness
• Back pain

Serious side effects may include:

• Allergic reactions: Get emergency medical help right away if you experience hives, difficulty breathing, or swelling of the face, lips, tongue, or throat
• Severely low blood pressure
• High potassium levels
• Worsening of kidney function in people with kidney problems

Who should not take losartan?

Losartan’s prescribing label lists some contraindications, meaning situations in which you should not take losartan. Certain patients should never take losartan, including the following:

• Patients who are allergic: People who are allergic to losartan or any ingredient in the medication should not take it.
• People with diabetes who take aliskiren: Patients with diabetes who take aliskiren should not take losartan.

Safety considerations:

• Losartan has a black box warning stating that it should not be taken by pregnant women, because it could cause harm or death to the unborn baby. If you already take losartan and find out you are pregnant, notify your healthcare provider right away. Women who are breastfeeding should not take losartan because it is not known if losartan passes into breast milk.
• Before taking losartan, tell your healthcare provider if you have kidney or liver problems, are dehydrated or volume-depleted, or have hyperkalemia (high potassium levels).

What medications interact with losartan?

Before taking losartan, tell your healthcare provider about any allergies or reactions to medications, as well as the  prescription and OTC drugs, vitamins, and supplements you take. Examples of losartan drug interactions include:

• Drugs that increase potassium: Drugs or supplements that increase potassium, when combined with losartan, can cause high potassium levels. Potassium levels should be monitored. Examples of these drugs include potassium-sparing diuretics (such as spironolactone) and potassium supplements.
• Lithium: Combining lithium and losartan can increase lithium levels in the body and cause lithium toxicity. Lithium levels should be monitored closely if these drugs are taken together.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs can cause kidney problems, including kidney failure, in older adults, patients who take diuretics or are volume-depleted, and patients who have a history of kidney problems. Examples of NSAIDs include Celebrex (celecoxib), Mobic (meloxicam), Motrin (ibuprofen), and naproxen. Individuals who take an NSAID along with losartan will need to have their kidney function monitored. NSAIDs may also make losartan less effective.
• Dual blockage of the renin-angiotensin system (RAS): Besides losartan, other drugs work on the RAS—but in different ways—such as ACE inhibitors (like lisinopril or ramipril) and Tekturna (aliskiren). Combining one of these drugs (or another ARB such as valsartan) with losartan can increase the risk of low blood pressure, fainting, high potassium levels, and kidney problems or kidney failure. In most cases, two drugs that work on the RAS will not be combined. Patients who do need to take a combination of these drugs will be closely monitored.
• Aliskiren or any medications containg aliskiren should never be taken with losartan in patients with kidney problems and diabetes.

Some drugs can interact with certain foods or substances. For losartan, this may include:

• Alcohol: Alcohol can lower blood pressure, as does losartan. Ask your healthcare provider how much alcohol, if any, is safe for you to consume.
• Caffeine: Talk to your healthcare provider about caffeine consumption. Caffeine can increase blood pressure.
• Potassium supplements: Check with your healthcare provider before using salt substitutes containing potassium.

This is not a full list of drug interactions, and others may occur. Consult your healthcare provider for a full list of drug interactions.

Losartan alternatives

There are many alternatives to losartan. Some patients may need an alternative, while others may need additional blood pressure control, so the best option would depend on the reason for seeking an alternative, among other individual patient factors.

For example, another ARB may be an option for a replacement, but would not be combined with losartan. Some other ARBs include:

• Benicar (olmesartan): This medication is available in brand and generic forms. It can be used alone or with other medications to treat high blood pressure in adults and children aged 6 years and older.
• Diovan (valsartan): Diovan is also available as a brand and generic forms. It can be used alone or with other medications to treat high blood pressure in adults and children aged 1 year and older. It can also be used to lower the risk of hospitalization in adults with heart failure or to lower the risk of death after a heart attack in adults with left ventricular failure or left ventricular dysfunction.
• Edarbi (azilsartan): Edarbi is available as a brand and generic. Edarbi can be used alone or with other medications to treat high blood pressure in adults. It is not approved for use in children.

Another replacement could be an ACE inhibitor.. Like ARBs, it would be a replacement, not a combination with losartan. Examples include:

• Altace (ramipril): This drug is now available only in generic form (as ramipril) and can be used alone or with a thiazide diuretic (such as hydrochlorothiazide) to treat high blood pressure in adults. It can also be used in adults 55 years and older at high risk of a major cardiovascular event (such as heart attack, stroke, or cardiovascular death) due to other risk factors. It can also be used after a heart attack in patients with congestive heart failure.
• Vasotec (enalapril): Vasotec is available in brand and generic forms and can be used alone or with other medicines to treat high blood pressure in adults and children one month and older. It can also be used with diuretics and digoxin to treat heart failure. Another use is reducing the risk of heart failure in patients with left ventricular dysfunction.
• Zestril (lisinopril): Zestril is available as a brand and generic. It can be used alone or with other medications to lower blood pressure in adults and children 6 years and older. It can also be used to treat heart failure. Another use is to reduce the risk of death after a heart attack, along with other medications.

Note: Some people experience a dry cough as a side effect of ACE inhibitors. If you are taking an ACE inhibitor and experience a dry cough, consult your healthcare provider.

Some patients may tolerate losartan well, but if they don’t, healthcare providers may prescribe other blood pressure medications.

For example, they may add a diuretic, such as hydrochlorothiazide, for additional blood pressure control. Or, instead of prescribing losartan and hydrochlorothiazide separately, the healthcare provider may prescribe Hyzaar, which contains both.

In some cases, a beta blocker or calcium channel blocker may be substituted or added. Examples include Tenormin (atenolol), Toprol XL (metoprolol succinate extended-release), and Norvasc (amlodipine).

Frequently asked questions

What is the main use of losartan?

Losartan is primarily used to treat high blood pressure, and it is also FDA-approved to reduce stroke risk and treat diabetic nephropathy in certain patients. Losartan is also sometimes prescribed off-label for heart failure.

Is losartan a beta blocker?

Losartan is not a beta blocker. It is an angiotensin receptor blocker, or ARB.

How quickly does losartan lower blood pressure?

While individual results may vary, the prescribing information says that losartan has substantial effects in the first week, but may take up to six weeks to reach its full effect.