Treating high blood pressure. It is also used to reduce the risk of stroke in certain patients with high blood pressure and for treating kidney disease in certain patients with type 2 diabetes.

Losartan is an angiotensin-2 receptor antagonist. It works by blocking the action of angiotensin-2 in the body, which relaxes blood vessels and helps the kidneys to eliminate extra sodium and fluids.

Do NOT use Losartan if:

• you are allergic to any ingredient in Losartan
• you are pregnant
• the patient is a child with severely decreased kidney function

Contact your doctor or health care provider right away if any of these apply to you.

Before using Losartan :

Some medical conditions may interact with Losartan. Tell your health care provider if you have any medical conditions, especially if any of the following apply to you:

• if you are planning to become pregnant or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have kidney problems, liver problems, congestive heart failure, blood electrolyte problems (eg, low sodium levels or high potassium levels), or low fluid volume (eg, dehydration)

Some MEDICINES MAY INTERACT with Losartan. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Potassium or potassium-sparing diuretics (eg, spironolactone) because the risk of irregular heartbeat due to high blood potassium levels may be increased
• Indomethacin because it may decrease Losartan 's effectiveness
• Lithium because the risk of its side effects may be increased by Losartan

This may not be a complete list of all interactions that may occur. Ask your health care provider if Losartan may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Losartan :

Use Losartan as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Take Losartan by mouth with or without food.
• Take this medicine on a regular schedule to get the most benefit from it. Continue to take Losartan even if you feel well. Do not miss any doses.
• If you miss a dose of Losartan , take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Losartan.

Important safety information:

• Losartan may cause dizziness. This effect may be worse if you take it with alcohol or certain medicines. Use Losartan with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
• Losartan may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
• Check with your doctor before you use a salt substitute or a product that has potassium in it.
• Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel "normal." Tell your doctor if you develop any new symptoms.
• Losartan has not been shown to reduce the risk of stroke or certain heart problems in black patients who have high blood pressure.
• Diabetes patients - Losartan may affect your blood sugar. Check blood sugar levels closely. Ask your doctor before you change the dose of your diabetes medicine.
• Lab tests, including liver function, kidney function, and blood pressure, may be performed while you use Losartan. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Losartan should not be used in CHILDREN younger than 6 years old; safety and effectiveness in these children have not been confirmed.
• Losartan is not recommended for use in CHILDREN who have severely decreased kidney function.
• PREGNANCY and BREAST-FEEDING: Do not take Losartan after the third month of pregnancy. It may cause injury or death to the fetus. If you become pregnant, contact your doctor right away. It is unknown if Losartan is found in breast milk. Do not breast-feed while taking Losartan.

Possible side effects of Losartan :

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; dizziness; tiredness; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; dark urine; decreased amount of urine; hoarseness; irregular heartbeat; muscle pain or tenderness; stomach pain; yellowing of the eyes or skin.