A prescription drug sold in the form of a film-coated oral tablet, sold by brand name Benicar or in generic form. You may take olmesartan as part of a combination therapy with other blood pressure-lowering drugs.

  1. Olmesartan oral tablet is available as a brand-name drug and a generic drug. Brand name: Benicar.
  2. Olmesartan comes only as a tablet you take by mouth.
  3. Olmesartan is used to treat high blood pressure.

FDA warning: Avoid use during pregnancy

  • This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.
  • You shouldn’t use this drug during pregnancy. Olmesartan can harm or end your pregnancy. If you become pregnant, stop taking olmesartan right away and call your doctor. If you plan to get pregnant, talk to your doctor about other ways to lower your blood pressure.
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Other warnings

  • Low blood pressure warning: This drug can cause your blood pressure to drop too low. If you also take a diuretic (water pill) or if you’re dehydrated, you have a higher risk of your blood pressure dropping too low. This may cause dizziness, lightheadedness, and a headache.
  • Kidney damage warning: If you take olmesartan when your renin-angiotensin system is activated, you risk serious kidney damage. This system is activated if you don’t have enough fluid in your blood vessels. Your renin-angiotensin system is already active if you have heart failure or renal artery stenosis, follow a low-salt diet, or are dehydrated. Your doctor can tell you more.
  • Diarrhea and weight loss warning: If you take olmesartan for a long time (months to years), it can cause severe, long-term diarrhea with weight loss. If you have diarrhea and weight loss and your doctor can’t find another cause for it, you may need to stop taking this drug.

Olmesartan is a prescription drug. It comes as a film-coated oral tablet.

Olmesartan is available as the brand-name drug Benicar. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.

Olmesartan may be taken as part of a combination therapy with other blood pressure-lowering drugs.

Why it’s used

Olmesartan is used to treat high blood pressure. It may be used alone or in combination with other drugs to lower your blood pressure.

How it works

Olmesartan belongs to a class of drugs called angiotensin receptor blockers. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Olmesartan blocks the action of angiotensin II, a chemical in your body that causes your blood vessels to tighten and narrow. This drug helps to relax and widen your blood vessels. This lowers your blood pressure.

Olmesartan oral tablet doesn’t cause drowsiness, but it can cause other side effects.

More common side effects

The more common side effects that occur with olmesartan include:

  • back pain
  • bronchitis
  • diarrhea
  • headache
  • blood in your urine
  • high blood sugar
  • high triglycerides
  • flu-like symptoms, such as fever and body aches
  • sore throat, runny nose, and sinus infection

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Serious allergic reaction. Symptoms can include:
    • swelling of your face, lips, throat, or tongue
  • Low blood pressure (hypotension). Symptoms can include:
    • faintness
    • dizziness
  • Liver problems. Symptoms can include:
    • nausea
    • pain in the right upper part of your stomach
    • yellowing of the whites of your eyes and your skin
    • itchy skin
  • Kidney problems. Symptoms can include:
    • swelling of your feet, ankles, or hands
    • weight gain

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Stopping this drug

  • Don’t stop taking olmesartan without talking to your doctor. Stopping the drug suddenly may cause your blood pressure to spike (rise suddenly). This may increase your risk of a heart attack or stroke.
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Olmesartan oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with olmesartan are listed below.

Bipolar disorder drug interactions

Taking olmesartan with your bipolar medication may increase the levels of the bipolar disorder drug in your body. This may cause dangerous effects. Examples of these drugs include:

  • lithium

Blood pressure medications interactions

Taking certain blood pressure medications with olmesartan can increase your risk of high blood potassium levels, kidney damage, and low blood pressure (hypotension). Examples of these drugs include:

  • aliskiren
  • angiotensin receptor blockers (ARBs), such as:
    • losartan
    • valsartan
    • telmisartan
  • angiotensin-converting enzyme (ACE) inhibitors, such as:
    • captopril
    • enalapril
    • lisinopril

Nonsteroidal anti-inflammatory drugs (NSAIDs) interactions

Taking NSAIDs with olmesartan can increase your risk of kidney damage. Your risk may be higher if you’re a senior, take a diuretic, are dehydrated, or already have poor kidney function. Also, NSAIDs may decrease the effect of olmesartan. This means that it may not work as well to lower your blood pressure.

Examples of NSAIDs include:

  • ibuprofen
  • naproxen

Colesevelam interaction

Taking this cholesterol and diabetes medication with olmesartan can reduce the amount of olmesartan that your body absorbs. If you take both of these drugs, you should take olmesartan at least 4 hours before you take colesevelam.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

This drug comes with several warnings.

Allergy warning

This drug can cause a severe allergic reaction. Symptoms include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Alcohol interaction warning

Drinking alcohol while taking olmesartan can cause a sedative effect. This means you may have slowed reflexes, poor judgment, and sleepiness. This can be dangerous.

Warnings for people with certain health conditions

For people with an active renin-angiotensin system: This drug activates your renin-angiotensin system. If you have heart failure, renal artery stenosis, or low blood pressure (hypotension), your renin-angiotensin system is already active. If you take olmesartan when your renin-angiotensin system is active, you risk serious kidney damage.

For people with diabetes: Some research shows that high doses of olmesartan increase the risk of heart problems and death in people with diabetes. In addition, you shouldn’t take this drug if you have diabetes and are also taking aliskiren.

Warnings for other groups

For pregnant women: This drug is a category D pregnancy drug. That means two things:

  1. Research in humans has shown adverse effects to the fetus when the mother takes the drug.
  2. This drug should only be used during pregnancy in serious cases where it’s needed to treat a dangerous condition in the mother.

Talk to your doctor if you’re pregnant or planning to become pregnant. Ask your doctor to tell you about the specific harm that may be done to the fetus. This drug should be only used if the potential risk is acceptable given the drug’s potential benefit.

If you become pregnant while taking this drug, call your doctor right away.

For women who are breastfeeding: It isn’t known if this drug passes into breast milk. If it does, it may cause side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors: Older adults may process drugs more slowly. A typical adult dosage may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dosage or a different dosing schedule.

For children: This drug hasn’t been studied in children under 6 years of age and shouldn’t be used in children under the age of 1 year.

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Dosage for high blood pressure

Generic: Olmesartan

  • Form: oral tablet
  • Strengths: 5 mg, 20 mg, 40 mg

Brand: Benicar

  • Form: oral tablet
  • Strengths: 5 mg, 20 mg, 40 mg

Adult dosage (ages 17–64 years)

  • Typical starting dosage: 20 mg taken once per day.
  • Dosage increases: Your doctor may increase your dosage up to 40 mg after 2 weeks.

Child dosage (ages 6–16 years)

  • Typical starting dosage:
    • For children who weigh 44–77 pounds (20–35 kg): 10 mg taken once per day.
    • For children who weigh 77 pounds or more (35 kg or more): 20 mg taken once per day.
  • Dosage increases: After 2 weeks, your doctor may increase your child’s dosage to 20 mg if they were taking 10 mg, or 40 mg if they were taking 20 mg.

Child dosage (ages 0–5 years)

This drug hasn’t been studied in children younger than 6 years and shouldn’t be used in children under the age of 1 year.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dosage may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dosage or a different dosing schedule.

Special dosage considerations

  • If your child cannot swallow a tablet, an oral suspension can be made using the tablets. Ask your pharmacist to make this for you if needed.
  • If you have conditions that make you have less fluid in your body than normal, such as taking a diuretic every day or having dialysis for kidney problems, you may need a lower dosage at first. Your doctor will decide what’s best for you.
  • Your race may affect how well this drug works for you. Your doctor can tell you more.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Olmesartan oral tablet is used for long-term treatment. It comes with serious risks if you don’t take it as prescribed.

If you don’t take it at all: This drug reduces high blood pressure. Medications that lower your blood pressure reduce your risk of a stroke or heart attack. If you don’t take this drug, your risk of stroke or heart attack may be higher.

If you stop taking it suddenly: Don’t stop taking this drug without talking to your doctor. Stopping the drug suddenly may cause your blood pressure to spike (rise suddenly). This may increase your risk of a heart attack or stroke.

If you don’t take it on schedule: Your blood pressure may not improve or may get worse. You may have a higher risk of a heart attack or stroke.

If you take too much: If you take too much of this drug, you may have the following symptoms:

  • weakness
  • dizziness
  • feeling like your heart is pounding or beating slower

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: If you forget to take your dose, take it as soon as you remember. If it’s just a few hours until the time for your next dose, wait and only take one dose at that time.

Never try to catch up by taking two doses at once. This could cause dangerous side effects.

How to tell if the drug is working: Your blood pressure should be lower. Your doctor will monitor your blood pressure regularly.

Keep these considerations in mind if your doctor prescribes olmesartan for you.

General

  • This drug may be taken with or without food.
  • You can crush or cut the tablet.

Storage

  • Store this drug at room temperature between 68°F and 77°F (20°C and 25°C).
  • Don’t freeze this drug.
  • Keep this drug away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t harm your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

You may need to check your blood pressure at home. To do this, you may need to buy a home blood pressure monitor.

You should keep a log with the date, time of day, and your blood pressure readings. Bring this diary with you to your doctor appointments.

Clinical monitoring

While you’re being treated with this drug, your doctor will monitor your:

  • blood pressure
  • kidney function
  • cholesterol levels
  • blood sugar levels

Hidden costs

If your doctor asks you to check your blood pressure at home, you’ll need a blood pressure monitor. These are available at most pharmacies.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline 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 other 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.