Generic name: losartan [ loe-SAR-tan ]
Dosage form: oral tablet (100 mg; 25 mg; 50 mg)
Drug class: Angiotensin receptor blockers

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 22, 2023.

What is Cozaar?

Cozaar is used alone or in combination with other medications to treat high blood pressure in adults and children at least 6 years old.

Cozaar is also used to decrease the risk of stroke in people who have high blood pressure and a heart condition called left ventricular hypertrophy (enlargement of the walls of the left side of the heart).

Losartan may not decrease the risk of stroke in African Americans who have these conditions.

Cozaar is also used to treat kidney disease in people who have type 2 diabetes (condition in which the body does not use insulin normally and therefore cannot control the amount of sugar in the blood) and high blood pressure.

Cozaar belomgs to a class of medications called angiotensin II receptor antagonists. It works by blocking the action of certain natural substances that tighten the blood vessels, allowing the blood to flow more smoothly and the heart to pump more efficiently.

Warnings

Do not use Cozaar if you are pregnant, and tell your doctor right away if you become pregnant. Losartan can cause injury or death to the unborn baby during your second or third trimester.

If you have diabetes, do not use Cozaar together with any medication that contains aliskiren (a blood pressure medicine).

You may also need to avoid taking Cozaar with aliskiren if you have kidney disease.

In rare cases, Cozaar 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.

Before taking this medicine

You should not use Cozaar if you are allergic to losartan.

If you have diabetes, do not take Cozaar with any medication that contains aliskiren (a blood pressure medicine).

To make sure Cozaar is safe for you, tell your doctor if you have ever had:

• heart disease or congestive heart failure;

• an electrolyte imbalance (such as high levels of potassium in your blood);

• if you are on a low-salt diet;

• liver disease; or

• kidney disease.

You may also need to avoid taking Cozaar with aliskiren if you have kidney disease.

Stop using Cozaar and tell your doctor right away if you become pregnant. Losartan can cause injury or death to the unborn baby if you use the medicine during your second or third trimester.

Tell your doctor if you are breastfeeding.

How should I take Cozaar?

Take Cozaar exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Cozaar is usually taken once per day.

You may take Cozaar with or without food.

Call your doctor if you are sick with vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking Cozaar. This can lead to very low blood pressure, a serious electrolyte imbalance, or kidney failure.

Your blood pressure will need to be checked often and you may need frequent blood tests.

If you have high blood pressure, keep using Cozaar even if you feel well. High blood pressure often has no symptoms.

Store tightly closed at room temperature, away from moisture, heat, and light.

Dosing information

Usual Adult Dose of Cozaar for Diabetic Nephropathy:

Initial dose: 50 mg orally once a day
Maximum dose: 100 mg orally once a day

Comments:
-If hypertensive patients with left ventricular hypertrophy or type 2 diabetic nephropathy patients require titration from initial dose, increase to 100 mg orally once a day.
-Antihypertension is substantially present within 1 week but in some studies the maximal effect occurred in 3 to 6 weeks.

Uses:
-Treatment of hypertension.
-To reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy.
-Treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria (urinary albumin to creatinine ratio 300 mg/g or greater) in patients with type 2 diabetes and a history of hypertension.

Usual Adult Dose of Cozaar for Hypertension:

Initial dose: 50 mg orally once a day
Maximum dose: 100 mg orally once a day

Comments:
-If hypertensive patients with left ventricular hypertrophy or type 2 diabetic nephropathy patients require titration from initial dose, increase to 100 mg orally once a day.
-Antihypertension is substantially present within 1 week but in some studies the maximal effect occurred in 3 to 6 weeks.

Uses:
-Treatment of hypertension.
-To reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy.
-Treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria (urinary albumin to creatinine ratio 300 mg/g or greater) in patients with type 2 diabetes and a history of hypertension.

Usual Pediatric Dose for Hypertension:

6 Years or Older:
Initial dose: 0.7 mg/kg orally once a day (up to 50 mg total)

Comments:
-May be given as a tablet or suspension.
-Doses above 1.4 mg/kg (or 100 mg) daily have not been studied in pediatric patients.

Related/similar drugs

amlodipine, lisinopril, metoprolol, losartan, furosemide, hydrochlorothiazide, enalapril, captopril, ramipril, irbesartan

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

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 Cozaar?

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Do not use potassium supplements or salt substitutes, unless your doctor has told you to.

Cozaar side effects

Get emergency medical help if you have signs of an allergic reaction to Cozaar: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Losartan may cause serious side effects. Call your doctor at once if you have:

• a light-headed feeling, like you might pass out;

• high blood potassium - nausea, weakness, tingly feeling, chest pain, irregular heartbeats, loss of movement; or

• kidney problems - swelling, urinating less, feeling tired or short of breath.

Common Cozaar side effects may include:

• dizziness, tiredness;

• low blood pressure;

• low blood sugar;

• diarrhea;

• back pain; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

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.

What other drugs will affect Cozaar?

Sometimes it is not safe to use certain medicines at the same time. Some drugs can affect your blood levels of other drugs you use, which may increase side effects or make the medicines less effective.

Tell your doctor about all your other medicines, especially:

• a diuretic or "water pill" that may increase blood potassium such as spironolactone, triamterene, amiloride;

• NSAIDs (nonsteroidal anti-inflammatory drugs) - aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others; or

• heart or blood pressure medication.

This list is not complete. Other drugs may interact with losartan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Ingredients

Active ingredient: losartan potassium.
Inactive ingredients: microcrystalline cellulose, lactose hydrous, pregelatinized starch, magnesium stearate, hydroxypropyl cellulose, hypromellose, and titanium dioxide.

Manufacturer

Organon & Co., Jersey City, NJ 07302, USA.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Cozaar only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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