Losartan side effects and tips for managing them

Key takeaways

• Losartan oral tablet is used to treat high blood pressure and diabetic kidney disease and lower the risk of stroke. It’s an angiotensin II receptor blocker (ARB) that may cause mild or serious side effects, including dizziness and harm to a fetus if taken during pregnancy.
• Common side effects include dizziness, upper respiratory infections like the common cold, a stuffy nose, and back pain. Most mild side effects are temporary and can be easily managed.
• Serious side effects that require immediate medical attention include kidney problems, heart problems, low blood pressure when standing up, high blood potassium levels, and severe allergic reactions.

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Overview

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

• treat high blood pressure in adults and some children
• treat diabetic kidney disease in certain adults
• lower the risk of stroke in adults with high blood pressure and left ventricular hypertrophy*

This article describes possible side effects of losartan oral tablet. You’ll also find information on cost savings and coupon options for losartan.

You can explore this overview article to learn more about losartan oral tablet, including the drug’s uses, dosage, and ways to save on cost.

* A person’s race may affect how their body responds to losartan oral tablet for this condition. To learn more, talk with your doctor.

Boxed warning: Risk of harm to a fetus if taken during pregnancy

Losartan has a boxed warning for the risk of harm to a fetus if taken during pregnancy. Boxed warnings are serious warnings from the Food and Drug Administration (FDA).

For details, see “Losartan and pregnancy” in the “Warnings for losartan” section.

More common side effects of losartan

Losartan oral tablet may cause mild or serious side effects. The following are some of the more common side effects of this medication.

Commonly reported side effects of losartan oral tablet include:

• dizziness
• upper respiratory infections, such as the common cold
• stuffy nose
• back pain

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Mild side effects of losartan

Losartan may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.

Mild side effects of losartan oral tablet that occurred in studies include:

• abdominal pain
• constipation
• dizziness or headache
• upper respiratory infection, such as a common cold
• sleep problems
• itchy skin
• muscle, joint, or back pain
• nausea or vomiting
• ringing in the ears
• shortness of breath
• sleepiness
• sensitivity to sunlight
• vertigo
• mild allergic reaction

Losartan oral tablet may cause more mild side effects than those listed. For details, see the drug’s prescribing information.

Serious side effects of losartan

Losartan may cause certain serious side effects. If you have any serious side effects from losartan oral tablet, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking losartan and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088. 

Serious side effects of losartan oral tablet that occurred in studies include:

• depression
• worsening kidney function
• heart problems, including heart palpitations and atrial fibrillation
• low red blood cell level
• migraine
• numbness or tingling in the arms, legs, hands, or feet
• low blood pressure when sitting or standing up*
• high blood potassium level*
• risk of harm to a fetus if taken during pregnancy†
• severe allergic reaction*

* To learn more about this side effect, see the “Side effects of losartan in detail” section.
† Losartan oral tablet has a boxed warning for this side effect. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). To learn more, see “Losartan and pregnancy” in the “Warnings for losartan” section.

Frequently asked questions about losartan side effects

Here are answers to some common questions about the side effects of losartan oral tablet. If you have other questions, talk with your doctor or pharmacist.

Does losartan cause long-term side effects?

It’s possible for losartan to cause long-term side effects in rare cases. Long-term side effects are those that start either:

• during treatment and continue for a long time, possibly after you’ve stopped taking the drug, or
• after you’ve taken the drug for a long time or have ended treatment

Long-term side effects reported in people taking losartan include:

• low blood pressure when sitting or standing up
• high blood potassium level
• risk of harm to a fetus if taken during pregnancy

Talk with a doctor or pharmacist if you have more questions about losartan’s long-term side effects.

Does losartan 25 mg cause different side effects than the drug’s other strengths?

Different strengths of losartan don’t cause different side effects. Side effects are the same for any strength of the drug.

That said, as with many drugs, your risk of side effects may increase if you take a higher dose. A doctor or pharmacist can answer questions about how your losartan dose affects your risk of side effects. But different strengths and doses aren’t expected to cause different side effects.

Does losartan cause weight gain?

Weight gain wasn’t a side effect reported in the studies. But losartan can cause worsening kidney function in people with a kidney problem, such as chronic kidney disease. Unexplained weight gain can be a symptom of worsening kidney function. Other symptoms include swelling in your ankles, feet, or hands.

You should tell your doctor right away if you have a kidney problem and notice these symptoms while taking losartan. Your doctor can recommend ways to manage your condition.

Tips for managing losartan side effects

Here you’ll find tips for managing some of the side effects of losartan oral tablet.

Low blood pressure

You may experience low blood pressure when sitting up or standing up while taking losartan. This side effect is called orthostatic hypotension. It wasn’t common in the drug’s studies.

Symptoms can include:

• feeling dizzy or lightheaded when standing or sitting up, which may lead to falls or fainting
• nausea
• weakness
• blurry vision

If you feel dizzy or lightheaded when standing or sitting up while taking losartan, lie down right away. Then, call your doctor. They can examine you and advise whether it’s safe for you to keep taking losartan.

High blood potassium

Treatment with losartan can cause high blood potassium as a side effect. This was rare in the drug’s studies.

Symptoms of high blood potassium include:

• tiredness or weakness
• heart palpitations
• numbness or tingling in your body
• trouble breathing

In some cases, especially when this condition is mild, high blood potassium may not cause symptoms.

Your doctor will likely suggest you avoid using salt substitutes containing potassium if you’re taking losartan. They’ll also likely suggest you avoid taking any potassium supplements.

Your doctor will monitor your potassium level during treatment with losartan using a blood test. They can provide more information on how often they’ll order this test.

Allergic reaction

For some people, losartan oral tablet can cause an allergic reaction. It’s not clear whether this side effect happened in studies. But it has been reported since losartan was approved for use.

Symptoms can be mild or serious, and they may include:

• itchiness
• skin rash
• swelling under the skin, usually affecting eyelids, lips, hands, or feet
• swelling of the mouth, tongue, or throat, which can make it hard to breathe
• flushing (temporary warmth, redness, or deepening of skin color)

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to losartan oral tablet, your doctor may recommend taking a different medication instead.

Coupon for losartan

Visit this page to access Optum Perks coupons and get price estimates for losartan when you use the coupons. These coupons can provide significant savings on your prescription costs. 

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

If you need help covering the cost of medications, the free Optum Perks Discount Card could help you save up to 80% on prescription drugs. Plus, you can now get them delivered to your home in as little as 3 days. Search for your medication here.

Warnings for losartan

You may want to discuss the following factors with your doctor before taking losartan oral tablet.

Boxed warning: Risk of harm to a fetus if used during pregnancy

Losartan has a boxed warning for risk of harm to a fetus if used during pregnancy. Boxed warnings are serious warnings from the Food and Drug Administration (FDA).

For details, see the “Losartan and pregnancy” section.

Other warnings

It may not be safe for you to take losartan oral tablet if you have specific health conditions. These are sometimes called drug-condition interactions. Other factors may also affect whether losartan oral tablet is a safe treatment option for you.

Before taking losartan oral tablet, tell your doctor about your health and medications you take. Factors to consider include:

• liver problems
• past allergic reaction to losartan

Losartan and pregnancy

You should not take losartan while pregnant. In fact, the drug has a boxed warning for the risk of harm to a fetus if taken during pregnancy. Boxed warnings are serious warnings from the Food and Drug Administration (FDA).

Risk of harm to a fetus if taken during pregnancy

Angiotensin II receptor blockers (ARBs), including losartan, should not be taken during pregnancy. Studies have shown that ARBs increase the risk of several types of harm when taken by a pregnant person.

Examples include:

• congenital anomalies (also called birth defects)
• premature birth
• pregnancy loss and stillbirth
• death in a newborn within the first month

Due to these risks, doctors will not prescribe losartan or any other ARB during pregnancy, except in rare cases.

If you’re taking losartan and become pregnant, immediately stop taking the drug and call your doctor right away. Keep in mind, it’s important to continue treating high blood pressure during pregnancy. This is one of the conditions the drug treats.

Having unmanaged high blood pressure increases the risk of premature birth and complications during delivery. Your doctor can discuss other treatment options with you that are safer to take while you’re pregnant.

Losartan and breastfeeding

You should not breastfeed while taking losartan. It’s not known whether the drug passes into breast milk. But due to the possible risk of harm in a child who is breastfed, breastfeeding while taking losartan is not recommended.

Talk with your doctor to learn more about feeding options besides breastfeeding if you’re taking losartan.

Related articles

• How does losartan potassium treat high blood pressure?
• Losartan interactions
• Losartan tablet dosage

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.