8 Irbesartan Side Effects You Should Know About

Nearly half of U.S. adults have hypertension (high blood pressure), so the odds are good that you or someone you know has this health condition. Irbesartan (Avapro) is one of the many blood pressure medications available. It belongs to the angiotensin II receptor blocker (ARB) class of medications.

Besides managing hypertension, irbesartan is also FDA approved to treat diabetic nephropathy (kidney damage caused by diabetes). While irbesartan is generally well tolerated, it has some potential side effects that you should know about.

Irbesartan side effects at a glance

Many irbesartan side effects are mild and happen when the medication is first started. They should go away or get better over time. Don’t stop taking irbesartan without advice from a healthcare professional.

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Common irbesartan side effects include:

• Dizziness

• Lightheadedness

• Low blood pressure

• Tiredness

• Fatigue

• Diarrhea

• Indigestion

• Heartburn

Rare but serious irbesartan side effects include:

• High potassium levels

• Kidney damage

• Birth defects

• Allergic reactions

Below, we’ll look at eight irbesartan side effects in more detail and share tips on how to manage them.

1. Dizziness or lightheadedness

Dizziness is one of the most common irbesartan side effects. Dizziness is typical and expected when first starting blood pressure medications. In clinical trials, this side effect was more often reported by people taking irbesartan for diabetic nephropathy.

Quickly changing positions, such as by going from sitting to standing, can make dizziness worse. In severe cases, this could cause you to fall or faint. So be sure to move slowly and hold onto a sturdy surface when you stand up. This can help prevent falls.

EXPERT PICKS: WHAT TO READ NEXT

• How do ARBs work? Get your questions answered about how angiotensin II receptor blockers (ARBs) work, what they treat, and more.

• More about ARB side effects: Irbesartan causes similar side effects to other ARBs. Read more about how ARB side effects differ between medications.

• Living with hypertension: Read how one woman manages her hypertension with a combination of medications, dietary changes, and stress reduction.

Dizziness with irbesartan is usually a temporary side effect. It generally gets better or goes away after your body adjusts to the medication. If your dizziness doesn't go away or you feel like you may pass out, contact your healthcare team. You may need a lower dosage or a different medication.

2. Low blood pressure

Lower blood pressure is expected when taking irbesartan. But sometimes blood pressure can drop too low (called hypotension). If this happens, you may feel lightheaded, have blurry vision, or feel weak. This can happen if your irbesartan dosage is too high.

You may have a greater risk of low blood pressure if you take irbesartan along with other blood pressure medications. This is particularly the case when irbesartan is combined with high doses of diuretics (water pills). Some examples of diuretics include:

• Furosemide (Lasix)

• Hydrochlorothiazide (Microzide)

• Chlorthalidone (Thalitone)

When starting irbesartan, ask your prescriber if you should check your blood pressure at home. Discuss with them what numbers are ideal for you. If you experience low blood pressure after starting irbesartan, let your prescriber know. They may lower your irbesartan dosage.

3. Tiredness

Many medications can make you feel tired or fatigued. Certain types of blood pressure medications, such as beta blockers, are more likely than others to cause fatigue. But it’s possible to have this side effect with irbesartan, too.

This side effect is more likely to happen when you first start irbesartan because it’s working to lower your blood pressure. It may also happen shortly after raising your dose. Tiredness typically goes away after you’ve been taking a steady dose for a little while.

There are ways you can manage tiredness at home until your body adjusts to irbesartan:

• Try to exercise regularly or find other ways to be more active.

• Pick nutrient-dense foods for meals and snacks. Try to avoid processed foods and those high in sodium.

• Make sure you’re getting enough rest at night. Try to optimize your sleep routine to help boost the quality of sleep you’re getting.

If tiredness with irbesartan seems excessive or interferes with your daily activities, let your healthcare team know. Severe fatigue isn’t typical. If this happens, your irbesartan dose may be too high, or there may be something else causing your tiredness.

4. Heartburn

Indigestion and heartburn can sometimes happen when taking irbesartan. If irbesartan bothers your stomach, try taking it with food. You can also try taking it in the morning if it’s causing nighttime reflux.

Other home remedies may help manage this irbesartan side effect, including herbal teas like fennel or ginger. Your pharmacist can also recommend over-the-counter (OTC) heartburn medications you can try. Contact your prescriber if your heartburn feels severe or doesn’t go away on its own.

5. Diarrhea

Diarrhea is a common side effect of some blood pressure medications, including irbesartan. This may happen shortly after starting irbesartan and should be mild. It usually goes away after taking the medication for a few days. Taking irbesartan with food might help lessen this side effect.

The most important thing to do if you experience diarrhea is to stay hydrated. Be sure to drink plenty of water or beverages containing electrolytes. This can help prevent dehydration.

Another option is OTC diarrhea medications. These can be helpful treatments for short-term relief. If diarrhea doesn’t go away or if it seems severe, talk to your prescriber. In rare cases, severe diarrhea can be a symptom of a digestive condition called sprue-like enteropathy. This complication may require you to stop irbesartan.

6. High potassium levels

High potassium is a rare irbesartan side effect that can become serious. It happens because of how the medication works. Irbesartan blocks the activity of a certain enzyme (protein) that contributes to high blood pressure. But this enzyme also plays a role in controlling the level of potassium in the body. And blocking it can sometimes prevent the body from removing extra potassium.

Most cases of high potassium due to irbesartan are mild and don’t cause noticeable symptoms. But severe cases can cause muscle weakness, vomiting, and abnormal heart rhythms. If caught early, complications can usually be prevented. Potassium levels should return to normal after a person stops irbesartan.

Potassium levels can be checked with a blood test. Your prescriber may have you get this blood test done before you start irbesartan. They may also suggest having the test done from time to time while you’re taking it. Make sure to go for any recommended tests on time. This can help catch changes in potassium levels before they get too high.

7. Kidney damage

As mentioned earlier, irbesartan can help slow down kidney damage caused by diabetes. And in most cases, it helps protect the kidneys when taken long term. However, irbesartan can also cause acute (sudden) kidney damage. While this is very rare, it can lead to serious complications if it happens.

Irbesartan can cause a build up of creatinine, a waste product that your kidneys normally get rid of. Oftentimes, this increase isn’t significant. But if creatinine levels get too high, it can put stress on your kidneys and cause damage. People with chronic kidney disease, severe heart failure, or existing kidney problems may have a higher risk for kidney damage when taking irbesartan.

Taking other medications that can cause kidney damage may also raise the risk of this rare irbesartan side effect. Examples of these medications include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin)

• Corticosteroids, such as prednisone

• Diuretics

Your healthcare team will likely recommend routine blood tests to monitor your kidney function while taking irbesartan. This can help them make sure your kidneys are working properly and catch potential issues as soon as possible. Make sure to go for these blood tests on time.

If you notice that you stop urinating as much as usual while on irbesartan, or if you have swelling in your legs or arms, contact your prescriber. These are possible symptoms of kidney damage.

8. Birth defects

If you’re pregnant or planning to become pregnant, you shouldn’t take irbesartan. This medication stops hormones in a developing fetus from working properly. This can cause significant birth defects. Because of the risk, the FDA has put a boxed warning (the strictest warning given to medications) about birth defects on irbesartan’s labeling.

If you find out you’re pregnant while taking the medication, let your healthcare team know immediately. There are safer medications you can take to manage high blood pressure during pregnancy. You should also discuss these other options with your prescriber ahead of time if you’re thinking of becoming pregnant and currently take irbesartan.

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Written by:

Timothy Aungst, PharmD

Timothy Aungst, PharmD, has worked in pharmacy practice for the past decade with different roles and responsibilities. He has served as an associate professor of pharmacy practice for almost a decade, a clinical pharmacist in outpatient cardiology management, and now in home healthcare.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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