Losartan (By mouth)

Losartan (loe-SAR-tan)

Treats high blood pressure. Reduces the risk of stroke in patients with high blood pressure and an enlarged heart. Treats kidney disease in patients with diabetes. This medicine is an angiotensin receptor blocker (ARB).

Brand Name(s):

Cozaar

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to losartan, or if you are pregnant. Do not use this medicine together with aliskiren if you have diabetes.

How to Use This Medicine:

Tablet

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Drink plenty of fluids if you exercise, sweat more than usual, or have diarrhea or vomiting.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how losartan works. Tell your doctor if you are using any of the following:
    • Lithium
    • Rifampin
    • A diuretic (water pill), such as spironolactone, triamterene, or amiloride
    • NSAID pain or arthritis medicine, such as aspirin, diclofenac, ibuprofen, or naproxen
    • Another blood pressure medicine, such as aliskiren, benazepril, enalapril, or lisinopril
  • Ask your doctor before you use any medicine, supplement, or salt substitute that contains potassium.

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant.
  • Tell your doctor if you are breastfeeding, or if you have kidney disease, liver disease, congestive heart failure, or diabetes. Tell your doctor if you have had angioedema that was caused by a blood pressure medicine.
  • This medicine could lower your blood pressure too much, especially when you first use it or if you are dehydrated. Stand or sit up slowly if you feel lightheaded or dizzy.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Change in how much or how often you urinate
  • Confusion, weakness, uneven heartbeat, trouble breathing, numbness or tingling in your hands, feet, or lips
  • Lightheadedness, dizziness, fainting
  • Rapid weight gain, swelling in your hands, ankles, or feet

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea
  • Tiredness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 9/6/2024

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

All rights reserved

A.D.A.M. content is best viewed in IE9 or above, Firefox and chrome browser.