Olmesartan/hydrochlorothiazide | Side Effects, Dosage, Uses & More

Generic Name:

hydrochlorothiazide-olmesartan, Oral tablet

All Brands

  • Benicar HCT
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Highlights for hydrochlorothiazide-olmesartan

Oral tablet
1

Olmesartan/hydrochlorothiazide is used to treat hypertension (high blood pressure). Medications that lower blood pressure help reduce your risk of stroke or heart attack.

2

Olmesartan/hydrochlorothiazide comes in the form of a tablet you take by mouth. The tablet contains two different drugs: olmesartan and hydrochlorothiazide. These medications work together to help lower your blood pressure.

3

Olmesartan/hydrochlorothiazide is available as a brand-name drug called Benicar HCT. It’s not available as a generic drug.

4

The more common side effects that can occur with this drug include nausea, dizziness, or respiratory tract infections.

5

Olmesartan/hydrochlorothiazide can harm or even end a pregnancy. If you get pregnant while taking this drug, tell your doctor right away.

IMPORTANT INFORMATION

FDA warning

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 to potentially dangerous effects.

Pregnancy warning: This drug can harm or even end a pregnancy. If you get pregnant while taking this drug, tell your doctor right away. Talk to your doctor about other ways to lower your blood pressure instead of using this drug.

Women of childbearing age should use reliable birth control while taking this drug.

Hypotension (low blood pressure)

Using this drug may cause low blood pressure. You’re more likely to have low blood pressure with this drug if you also take diuretics, are on a low-salt diet, are on hemodialysis, have heart problems, or get sick with vomiting or diarrhea. If you have any of these medical problems, your doctor may monitor you closely when you receive your first dose.

Eye problems

The hydrochlorothiazide part of this combination drug can cause eye problems called myopias or glaucoma. If your vision starts to get worse or you have pain in your eyes, stop using this drug and call your doctor right away.

Diarrhea and weight loss

This drug may cause severe, long-term diarrhea with weight loss if you take it for a long time (months to years). If your doctor can’t find another cause for your diarrhea and weight loss, you may need to stop taking this drug.

Drug features

This drug is a prescription medication. It comes in the form of a tablet you take by mouth. 

The tablet contains two different drugs: olmesartan and hydrochlorothiazide. It’s important to know about both drugs in this combination product because each drug may affect you in a different way. 

Benicar HCT is a brand-name drug. It’s not available as a generic drug.  

This drug may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

This drug is used to treat hypertension (high blood pressure). Medications that lower blood pressure decrease your risk of stroke or heart attack.

How it works

Olmesartan belongs to a class of drugs called angiotensin II receptor antagonists. Hydrochlorothiazide belongs to a class of drugs called thiazide diuretics.

More Details

How it works

Olmesartan belongs to a class of drugs called angiotensin II receptor antagonists. Hydrochlorothiazide belongs to a class of drugs called thiazide diuretics. 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 and hydrochlorothiazide work together to lower your blood pressure. Olmesartan blocks the action of angiotensin II, a chemical in your body that causes blood vessels to tighten and narrow. This helps to relax and widen your blood vessels, which lowers your blood pressure. 

Hydrochlorothiazide works in your kidneys to remove sodium and water from your body. This also helps reduce blood pressure.

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hydrochlorothiazide-olmesartan Side Effects

Oral tablet

More Common Side Effects

The more common side effects that can occur with use of olmesartan/hydrochlorothiazide include:

  • nausea

  • dizziness

  • respiratory tract infections

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 9-1-1 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:

  • Hypotension (low blood pressure). Symptoms can include:

    • feeling faint or dizzy, especially upon standing
    • tiredness
    • lightheadedness
  • Eye problems. Symptoms can include:

    • vision that gets worse
    • eye pain
  • Liver problems. Symptoms can include:

    • nausea
    • pain in the right upper abdomen (stomach area)
    • yellowing of your skin or the whites of your eyes
    • itchy skin
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug doesn’t cause drowsiness.

This drug may cause low blood pressure. This can make you feel faint, dizzy, or lightheaded soon after taking it. 

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.
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hydrochlorothiazide-olmesartan May Interact with Other Medications

Oral tablet

Olmesartan/hydrochlorothiazide 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.

Food interactions

Using olmesartan/hydrochlorothiazide may cause low blood pressure. If you’re on a low-salt diet, you’re more likely to have low blood pressure with this drug. Your doctor may closely monitor you when you receive your first dose of this drug.

Alcohol interaction

The use of drinks that contain alcohol raises your risk of a sudden drop in blood pressure from olmesartan/hydrochlorothiazide. You may feel dizzy, lightheaded, or faint, especially when you stand up from a sitting or lying position.

If you drink alcohol, talk to your doctor about how much alcohol is safe while taking this drug.

Medications that might interact with this drug

Blood pressure drugs

When taken with olmesartan/hydrochlorothiazide, certain drugs used to treat high blood pressure can cause your blood pressure to get too low. Examples of these drugs include:

  • Diuretics (water pills) such as:
    • amiloride
    • bumetanide
    • furosemide
    • spironolactone
    • torsemide
    • triamterene

When taken with olmesartan/hydrochlorothiazide, certain blood pressure drugs can cause kidney problems, as well as cause your blood pressure to get too low. Examples of these drugs include:

  • Angiotensin receptor blockers (ARBs) such as:
    • azilsartan 
    • candesartan
    • irbesartan
    • losartan
    • olmesartan
    • telmisartan
    • valsartan
  • Angiotensin-converting enzyme (ACE) inhibitors such as:
    • benazepril
    • captopril 
    • enalapril 
    • fosinopril
    • lisinopril
    • moexipril 
    • perindopril 
    • quinapril 
    • ramipril 
    • trandolapril
  • Aliskiren, a direct renin inhibitor 

Cholesterol drugs

When taken with olmesartan/hydrochlorothiazide, certain drugs used to treat high cholesterol can keep olmesartan/hydrochlorothiazide from working well. This means it may not control your blood pressure. Examples of these cholesterol drugs include: 

  • cholestyramine
  • colestipol

Taking olmesartan/hydrochlorothiazide with other types of cholesterol drugs can increase the amount of these drugs in your body. This raises your risk of side effects from these drugs. Examples of these cholesterol drugs include:

  • colesevelam
  • simvastatin

Diabetes drugs

When taken with certain drugs used to treat diabetes, olmesartan/hydrochlorothiazide can raise your blood sugar. If you have diabetes, you may need to test your blood sugar more often. Your doctor may adjust your diabetes medications. Examples of these diabetes drugs include:

  • insulin
  • glipizide
  • glyburide 
  • pioglitazone
  • rosiglitazone
  • acarbose
  • miglitol
  • sitagliptin
  • saxagliptin

Mood stabilizers (lithium)

Lithium is used to treat certain mood disorders. Taking olmesartan/hydrochlorothiazide with lithium can increase the amount of lithium in your body. This raises your risk of side effects from lithium, as well as a condition called lithium toxicity. Symptoms of this condition include diarrhea, seizures, or coma.

Muscle relaxants

Taking olmesartan/hydrochlorothiazide with certain drugs used to relax the muscles can increase the amount of these drugs in your body. This raises your risk of side effects from these muscle relaxants. Examples of these drugs include:

  • tubocurarine
  • pancuronium
  • rocuronium
  • vecuronium

Pain drugs

When taken with olmesartan/hydrochlorothiazide, certain drugs used to treat pain can cause your blood pressure to get too low. Examples of these drugs include:

  • Barbiturates, such as:
    • amobarbital
    • butabarbital
    • pentobarbital
  • Narcotics, such as:
    • morphine
    • oxycodone

Other types of pain drugs, when taken with olmesartan/hydrochlorothiazide, can cause problems with how your kidneys work. Examples of these drugs include: 

  • COX-2 inhibitors, such as:
    • celecoxib
    • meloxicam
  • NSAIDs (nonsteroidal anti-inflammatory drugs), such as:
    • ibuprofen
    • ketoprofen
    • naproxen

When taken with olmesartan/hydrochlorothiazide, NSAIDs can also keep the drug from working well. This means it may not control your blood pressure.

Other drugs

Corticosteroids are drugs used to treat many conditions. When used with olmesartan/hydrochlorothiazide, they can lower your potassium levels. Low potassium levels can lead to heart problems such as arrhythmias. Examples of these drugs include:

  • prednisone
  • methylprednisolone
  • cortisone

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.

People with liver problems

This drug is processed by your liver. If you have liver damage, this medication can make it worse. In some cases, it can even cause liver failure or death. If you have severe liver problems, be sure your doctor knows about your condition before you take this drug. You may need a lower dose or a different dosing schedule.

People with heart problems

Using this drug can cause low blood pressure. You’re more likely to have low blood pressure with this drug if you have heart problems such as heart failure. If you have heart problems, your doctor may closely monitor you when you receive your first dose of this drug.

People with lupus

This drug can cause lupus. If you already have lupus, this drug can cause more flare-ups from the condition.

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 to the fetus is acceptable given the drug’s potential benefit.

Women who are breast-feeding

This drug may pass into breast milk and can cause serious side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your child. You may need to decide whether to stop breast-feeding or stop taking this medication.

For seniors

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects. 

For children

This drug hasn’t been studied in children. It shouldn’t be used in people younger than 17 years.

When to call the doctor

Call your doctor right away if you become pregnant while using this drug.

Allergies

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

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

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 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).

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How to Take hydrochlorothiazide-olmesartan (Dosage)

Oral tablet

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

What are you taking this medication for?

Hypertension (High blood pressure)

Brand: Benicar HCT

Form: Oral tablet
Strengths: 20 mg olmesartan/12.5 mg hydrochlorothiazide, 40 mg olmesartan/12.5 mg hydrochlorothiazide, 40 mg olmesartan/25 mg hydrochlorothiazide
Adult dosage (ages 18–64 years)
  • Typical starting dosage: 20 mg olmesartan/12.5 mg hydrochlorothiazide once daily.
  • Increasing dosage: If needed, your doctor may increase your dose two weeks after you start treatment.
  • Maximum daily dosage: 40 mg olmesartan/25 mg hydrochlorothiazide once daily.
Child dosage (ages 0–17 years)

Olmesartan/hydrochlorothiazide hasn’t been studied in children. It shouldn’t be used in people younger than 17 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This increases your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

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 to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug comes with serious risks if you don't take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

Your blood pressure won’t be controlled. You may not feel different, but you’ll be at higher risk of stroke or heart attack if your blood pressure stays high. If you stop taking this drug suddenly, you may have a sudden increase in your blood pressure, with symptoms such as sweating, a fast heart rate, or anxiety.

If you miss doses or don’t take the drug on schedule

Your medication may not work as well. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • 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 9-1-1 or go to the nearest emergency room right away.   

What to do if you miss a dose

Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working

Your blood pressure should be lowered. You won’t feel different, but testing can tell you if the drug is working. You can do a blood pressure check at home using a blood pressure monitor. Or your doctor can check it for you.

This drug is used for long-term treatment.

Important considerations for taking this drug
taken with or without food This drug can be taken with or without food
timing Take this drug at the time(s) recommended by your doctor
can be cut or crushed This tablet can be cut or crushed
storage Store this drug carefully See Details
medication is refillable A prescription for this medication is refillable See Details
Travel Travel See Details
Self-management Self-management See Details
Clinical monitoring Clinical monitoring See Details
not usually stocked Not every pharmacy stocks this drug. When refilling your prescription, be sure to call ahead
Hidden costs Hidden costs See Details
prior authorization Insurance See Details

Store this drug carefully

  • Keep 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.

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 hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box 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

Your doctor may ask you to check your blood pressure at home. You can do this using a blood pressure monitor. You can find one at your local pharmacy. Your doctor or pharmacist can tell you how to use it.

Clinical monitoring

Your and your doctor should monitor certain health issues. This can help make sure you stay safe while you take this drug, and let your doctor know if your dosage should change. These issues include:

  • Blood pressure: You and your doctor should monitor your blood pressure. This will help make sure this drug is working for you.
  • Liver function: Blood tests will show if your liver is working well.
  • Kidney function: Blood tests will show if your kidneys are working well.
  • Blood potassium: Blood tests will show if the potassium in your blood is at a healthy level.

Hidden costs

Your doctor may ask you to check your blood pressure at home. To do this, you’ll need to buy a blood pressure monitor. You can find one at your local pharmacy.

You may need to have blood tests done to make sure this drug is safely managing your high blood pressure.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

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.

What does the pill look like?

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on October 10, 2015

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.
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