Medically reviewed on July 18, 2017.
What is hydrochlorothiazide and losartan?
Hydrochlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.
Losartan is an angiotensin II receptor antagonist. Losartan keeps blood vessels from narrowing, which lowers blood pressure and improves blood flow.
Hydrochlorothiazide and losartan is a combination medicine used to treat high blood pressure (hypertension). It is also used to lower the risk of stroke in certain people with heart disease.
Hydrochlorothiazide and losartan may also be used for purposes not listed in this medication guide.
Do not use if you are pregnant. If you become pregnant, stop taking this medicine and tell your doctor right away.
You should not use this medicine if you are unable to urinate.
Before taking this medicine
You should not use this medicine if you are allergic to hydrochlorothiazide or losartan, if you are unable to urinate.
If you have diabetes, do not use hydrochlorothiazide and losartan together with any medication that contains aliskiren (such as Tekturna or Tekamlo).
You may also need to avoid taking hydrochlorothiazide and losartan with aliskiren if you have kidney disease.
To make sure hydrochlorothiazide and losartan is safe for you, tell your doctor if you have ever had:
congestive heart failure;
low or high levels of potassium in your blood;
high cholesterol or triglyceride levels;
an allergy to penicillin or sulfa drugs.
Do not use if you are pregnant. If you become pregnant, stop taking this medicine and tell your doctor right away. Hydrochlorothiazide and losartan can cause injury or death to the unborn baby if you take the medicine during your second or third trimester.
Hydrochlorothiazide can pass into breast milk and may cause side effects in the nursing baby. You should not breast-feed while using this medicine.
How should I take hydrochlorothiazide and losartan?
Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Your blood pressure will need to be checked often.
Call your doctor if you have ongoing vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking this medication, which can lead to severely low blood pressure or a serious electrolyte imbalance.
If you need surgery or medical tests, tell the surgeon ahead of time that you are using hydrochlorothiazide and losartan.
It may take up to 4 weeks for this medication to control your blood pressure. Keep using this medicine as directed, even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking hydrochlorothiazide and losartan?
Do not use potassium supplements or salt substitutes while you are taking hydrochlorothiazide and losartan, unless your doctor has told you to.
Drinking alcohol can further lower your blood pressure and may cause side effects.
Avoid becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids.
Hydrochlorothiazide and losartan side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
In rare cases, hydrochlorothiazide and losartan can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.
Also call your doctor at once if you have:
eye pain, vision problems;
a light-headed feeling, like you might pass out;
jaundice (yellowing of the skin or eyes);
easy bruising, unusual bleeding;
kidney problems--little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath;
low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
high potassium--nausea, slow or unusual heart rate, weakness, loss of movement; or
Common side effects may include:
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect hydrochlorothiazide and losartan?
Tell your doctor about all your current medicines and any you start or stop using, especially:
any other blood pressure medications;
insulin or oral diabetes medicine;
This list is not complete. Other drugs may interact with hydrochlorothiazide and losartan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 13.01.
More about Hyzaar (hydrochlorothiazide / losartan)
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- Drug class: angiotensin II inhibitors with thiazides