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

When This Medicine Should Not Be Used:

How to Use This Medicine:

Liquid, 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.
• Oral liquid: Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup. Shake the bottle for 20 seconds before using.
• 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. Use the oral liquid within 60 days after opening.

Drugs and Foods to Avoid:

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

• Do not use this medicine together with aliskiren, especially if you have diabetes or kidney disease.
• Some medicines can affect how losartan works. Tell your doctor if you are using any of the following:
  • Lithium, rifampin
  • Blood pressure medicine, including ACE inhibitor
  • Diuretic (water pill)
  • NSAID pain or arthritis medicine, including aspirin, diclofenac, ibuprofen, or naproxen
• 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.
• Oral liquid: Do not breastfeed during treatment and for 2 days after the last dose.
• 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 had an allergic reaction (including angioedema) to a blood pressure medicine.
• This medicine may cause the following problems:
  • Hypotension (low blood pressure)
  • Kidney problems
• 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, or painful urination
• Confusion, weakness, uneven heartbeat, trouble breathing, numbness or tingling in your hands, feet, or lips
• Fever, chills, cough, runny or stuffy nose, sore throat, body aches
• 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:

• Back pain
• 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: 5/4/2025