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Generic Name:

hydrochlorothiazide-losartan, Oral tablet

All Brands

  • Hyzaar
SECTION 1 of 4

Highlights for hydrochlorothiazide-losartan

Oral tablet
1

Losartan/hydrochlorothiazide is a combination of two drugs in a single form that work in different ways to treat high blood pressure. It’s also used to reduce the risk of stroke in people with high blood pressure and damage to the heart (left ventricular hypertrophy).

2

The starting dose is 50 mg losartan/12.5 mg hydrochlorothiazide or 100 mg losartan/12.5 mg hydrochlorothiazide taken by mouth once per day.

3

This drug may cause lightheadedness and dizziness, especially in the first few days of taking it. If you faint, stop taking losartan/hydrochlorothiazide and call your doctor right away.

4

You shouldn’t take this drug during pregnancy. Losartan/hydrochlorothiazide can harm or be fatal to your developing baby.

5

Common side effects include upper respiratory infection, dizziness, cough, back pain, fast or irregular heart rate (heart palpitations), and skin rash.

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.

Use during pregnancy warning. You shouldn’t take this drug during pregnancy. This drug can harm or be fatal to your unborn baby. If you become pregnant, call your doctor and stop taking this drug right away.

Dizziness

If you’re also taking diuretic medications, you may feel dizzy when you first start taking this drug.

Sensitivity reaction

If you have a history of allergies or asthma, you may get a sensitivity reaction when you first start taking this drug. Symptoms include skin rash, hives, shortness of breath or wheezing, itching, and fever.

Eye problems

This drug may cause eye conditions called myopias and glaucoma. If you have trouble seeing or pain in your eyes, call your doctor and stop taking the drug right away.

What is losartan/hydrochlorothiazide?

This drug is a prescription drug. It is available as an oral tablet.

This drug is available as a generic drug. Generic drugs usually cost less. In some cases they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you.

This is a combination of two drugs in a single form. It is important to know about all the drugs in the combination because they each may have unique traits.

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

Why it's used

This drug is used treat high blood pressure. It’s given when one drug isn’t enough to lower your blood pressure.

More Details

How it works

This drug belongs to a class of drugs called angiotensin II receptor blockers and thiazide diuretics.

More Details

Why it's used

This drug is used treat high blood pressure. It’s given when one drug isn’t enough to lower your blood pressure.

This drug is also used to reduce the risk of stroke in people with high blood pressure and damage to the heart (left ventricular hypertrophy). The effectiveness of this drug may be related to your race. Ask your healthcare provider for more information about this topic.

How it works

This drug belongs to a class of drugs called angiotensin II receptor blockers and thiazide diuretics. A class of drugs refers to medications that work similarly. They have a similar chemical structure and are often used to treat similar conditions.

It’s thought that hydrochlorothiazide works to remove excess salt and water from your body. This keeps your heart from working as hard to pump blood. This lowers your blood pressure levels.

Losartan 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.

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SECTION 2 of 4

hydrochlorothiazide-losartan Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with losartan/hydrochlorothiazide include:

  • upper respiratory infection

  • dizziness

  • cough

  • back pain

  • fast or irregular heart rate (heart palpitations)

  • skin rash

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

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life-threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • serious allergic reaction. Symptoms include:

    • swelling of your face, lips, throat, or tongue
  • low blood pressure (hypotension). Symptoms include:

    • feeling like you’re going to faint
    •  dizziness
  • lupus. Symptoms include:

    • joint pain
    • stiffness
    • weight loss
    • fatigue
    • skin rash
  • liver problems. Symptoms include:

    • nausea
    • pain in your right upper stomach
    • yellowing of the whites of your eyes and skin
    • itchiness
  • kidney problems. Symptoms include:

    • swelling of your feet, ankles, or hands
    • weight gain
  • eye problems. Symptoms include:

    • trouble seeing
    • eye pain
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug does not cause drowsiness.

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.
SECTION 3 of 4

hydrochlorothiazide-losartan May Interact with Other Medications

Oral tablet

Losartan/hydrochlorothiazide can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol interaction

The use of drinks that contain alcohol can increase your risk of dizziness or lightheadedness from losartan/hydrochlorothiazide. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Potassium sparing diuretics and supplements, and salt substitutes

These medicines may increase the amount of potassium in your blood to unsafe levels. You shouldn’t take these drugs together.

These drugs include:

  • potassium-sparing diuretics
  • potassium supplements
  • salt substitutes

Bipolar disorder drugs

Taking these drugs together can increase the levels of your bipolar disorder drug in your blood. This can increase your chance for toxicity. Your doctor may reduce your dose of your bipolar disorder drug.

These drugs include:

  • lithium

Non-steroidal anti-inflammatory drugs (NSAIDs)

NSAIDs may reduce the effectiveness of losartan/hydrochlorothiazide. This means that it won’t work as well. Taking these drugs together may also damage your kidneys. You shouldn’t take these medicines together.

These drugs include:

  • ibuprofen
  • naproxen

Blood pressure drugs

Taking other drugs that work in the same way as losartan/hydrochlorothiazide may increase your chance of low blood pressure, high potassium levels in your blood, and kidney damage.

These drugs include:

  • angiotensin receptor blockers (ARBs), such as:
    • irbesartan
    • candesartan
    • valsartan
  • angiotensin-converting enzyme (ACE) inhibitors, such as:
    • lisinopril
    • fosinopril
    • enalapril
  • aliskiren

Diabetes drugs

Your doctor may adjust the dose of your diabetes medications while you’re taking losartan/hydrochlorothiazide.

These drugs include:

  • insulin
  • glipizide
  • glyburide
  • pioglitazin
  • rosiglitazone
  • acarbose
  • miglitol
  • sitaglilptin
  • saxagliptin

Cholesterol-lowering drugs

These drugs can decrease the amount of losartan/hydrochlorothiazide in your body. This means that it may not work as well. Your doctor may adjust the dose of losartan/hydrochlorothiazide if you’re taking this combination.

These drugs include:

  • cholestyramine
  • colestipol

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.
Drug warnings
sulfonamide allergy
People with a sulfonamide allergy

If you’re allergic to sulfonamides, don’t take this drug. Tell your doctor about all of your allergies.

kidney disease
People with kidney disease

If you have kidney disease, you have a higher risk of serious side effects. Your doctor will monitor your kidney function and adjust your medication as needed. 

liver disease
People with liver disease

You shouldn’t take this drug if you have liver disease. It can cause changes in your fluid and electrolytes. This may lead to a coma if you have liver disease.

lupus
People with lupus

This drug can cause new or worsening symptoms of lupus. Call your doctor right way if this occurs.

diabetes
People with diabetes

Your doctor may adjust the doses of your diabetes drugs while you’re taking this medicine. They’ll tell you how often to test your blood sugar levels. 

glaucoma
People with glaucoma

This drug may make your glaucoma worse.

pregnant women
Pregnant women

This drug is a pregnancy category D 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 only be used if the potential risk to the fetus is acceptable given the drug’s potential benefit.

breastfeeding
Women who are breast-feeding

It isn’t known if this drug passes into breast milk. If it does, it may cause side effects in a child who is breast-fed.

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

for seniors
For seniors

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule. You may also be more likely to have side effects of this drug.

for children
For children

This medicine hasn’t been studied in children and shouldn’t be used in children younger than 18 years.

call doctor
When to call the doctor

Call your doctor right away if you get pregnant while taking this drug.

allergies
Allergies

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

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

Don’t take this drug again if you’ve ever had an allergic reaction to it before. Taking it a second time after an allergic reaction could be fatal.

SECTION 4 of 4

How to Take hydrochlorothiazide-losartan (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?

High blood pressure (hypertension)

Brand: Hyzaar

Form: Oral tablet
Strengths:
  • 50 mg losartan/12.5 mg hydrochlorothiazide
  • 100 mg losartan/12.5 mg hydrochlorothiazide
  • 100 mg losartan/25 mg hydrochlorothiazide

Generic: losartan/hydrochlorothiazide

Form: Oral tablet
Strengths:
  • 50 mg losartan/12.5 mg hydrochlorothiazide
  • 100 mg losartan/12.5 mg hydrochlorothiazide
  • 100 mg losartan/25 mg hydrochlorothiazide
Adult dosage (ages 18–64 years)

The starting dose is 50 mg losartan/12.5 mg hydrochlorothiazide or 100 mg losartan/12.5 mg hydrochlorothiazide taken by mouth once per day. Your dose depends on the dose of the blood pressure drug that you were taking before. Your doctor may increase your dose up to to 100 mg losartan/25 mg hydrochlorothiazide taken once per day if needed.

Child dosage (ages 0–17 years)

This medicine hasn’t been studied in children and shouldn’t be used in children younger than 18 years.

Senior dosage (ages 65 years and older)

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

Special considerations

Kidney disease: You shouldn’t take this drug if your creatinine clearance (CrCl) is less than 30 ml/min.

Liver disease: You shouldn’t take this drug if you have liver damage because a lower starting dose of losartan is needed for people with liver disease. But it’s not available in the combination drug.

Warnings

The maximum dose is 100 mg losartan/25 mg hydrochlorothiazide taken once per day.

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
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

This drug 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. If this condition isn’t treated, it can lead to stroke, heart attack, heart failure, kidney failure, and vision problems. It can even be fatal.

If you stop taking it suddenly

Don’t stop taking this drug without talking to your doctor. High blood pressure can occur if you stop taking this drug too suddenly. This may increase your chance for a heart attack or stroke. If you need to stop taking this drug, your doctor will slowly decrease your dose.

If you don't take it on schedule

Your blood pressure may not improve or may get worse. You may have a higher chance of a heart attack or stroke.

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, then wait and only take one dose at that time. Never try to catch up by taking two doses at once. This could cause toxic side effects.

If you take too much

You may have more intense side effects, such as dizziness and changes in the amount of electrolytes in your blood. This may be dangerous.

How to tell this drug is working

You may be able to tell that this drug is working if your blood pressure is lower. Your doctor will monitor your blood pressure at your checkups. You can also check your blood pressure at home. Keep a log with the date, time of day, and your blood pressure readings. Bring this diary with you to your doctor appointments.

This drug is a long-term treatment for lowering blood pressure and reducing your risk for stroke.

It will control your blood pressure, but it won’t cure it.

This drug must be stored at the right temperature

  • Store this drug at room temperature close to 77°F (25°C). It may be stored briefly between 59°F (15°C) and 86°F (30°C).
  • Don’t freeze this drug.
  • Keep this drug away from light.
  • Keep it away from high temperature.
  • Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry it with you or in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt this medication.
  • You may need to show airport staff your pharmacy’s label to clearly identify the medication. Keep the original prescription label with you when traveling.
  • Don’t leave this medicine in the car, especially when the temperature is hot or freezing.

Self-management

You may need to check your blood pressure at home. 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.

You may need to buy your own blood pressure monitoring machine. These are available at most pharmacies.

Clinical monitoring

While you’re being treated with this drug, your doctor will check your blood pressure and do blood tests to monitor the following:

  • liver function
  • kidney function
  • blood sugar
  • blood potassium

Your diet

Your doctor may have you follow a diet, such as a low-salt or a low-potassium diet. You may have to avoid potassium supplements and salt substitutes containing potassium.

Hidden costs

You may need to purchase a blood pressure monitor to check your blood pressure at home.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.


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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 September 8, 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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