Losartan is used alone or together with other medicines to treat high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. Lowering blood pressure may reduce the risk of strokes and heart attacks.

Losartan is an angiotensin II receptor blocker (ARB). It works by blocking a substance in the body that causes blood vessels to tighten. As a result, losartan relaxes the blood vessels. A lower blood pressure will increase the supply of the blood and oxygen to the heart.

Losartan is also used to decrease the risk of stroke in patients with high blood pressure and enlargement of the heart. It is also used to treat kidney problems in patients with type 2 diabetes and a history of hypertension.

This medicine is available only with your doctor's prescription.

In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and changes in the types of foods you eat, especially foods high in sodium (salt). Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.

Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.

Remember that this medicine will not cure your high blood pressure but it does help control it. You must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life. If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.

This medicine may be taken with or without food.

If you are unable to swallow tablets, ask your pharmacist about preparing an oral suspension for you.

This medicine comes with a patient information insert. Read and follow the instructions carefully. Ask your doctor if you have any questions.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Abdominal or stomach pain

anxiety

bladder pain

bloody or cloudy urine

blurred vision

chills

cold sweats

coma

confusion

cool, pale skin

depression

difficult breathing

difficult, burning, or painful urination

dizziness

fast heartbeat

frequent urge to urinate

headache

increased hunger

irregular heartbeat

lower back or side pain

nausea or vomiting

nightmares

numbness or tingling in the hands, feet, or lips

pale skin

seizures

shakiness

shortness of breath

slurred speech

troubled breathing with exertion

unusual bleeding or bruising

unusual tiredness or weakness

weakness or heaviness of the legs

Rare

Arm, back, or jaw pain

chest pain or discomfort

chest tightness or heaviness

dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position

fainting

fast, irregular, pounding, or racing heartbeat or pulse

inability to speak

pain or discomfort in the arms, jaw, back, or neck

severe or sudden headache

sweating

swelling or puffiness of the face

temporary blindness

unsteadiness or awkwardness

weakness in the arm or leg on one side of the body, sudden and severe

weakness in the arms, hands, legs, or feet

Incidence not known

Black, tarry stools

bleeding gums

cough

dark urine

difficulty with swallowing

general tiredness and weakness

hives

itching

large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs

light-colored stools

muscle cramps or spasms

muscle pain or stiffness

pinpoint red spots on the skin

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

skin rash

upper right abdominal or stomach pain

yellow eyes and skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Blindness

body aches or pain

decreased vision

dry cough

ear congestion

loss of voice

nasal congestion

runny nose

sneezing

sore throat

Less common

Acid or sour stomach

back pain

belching

difficulty with moving

heartburn

increased sensitivity to pain

increased sensitivity to touch

indigestion

joint pain

lack or loss of strength

pain in the knees or legs

pain or tenderness around the eyes and cheekbones

stomach discomfort or upset

swollen joints

trouble sleeping

weight gain

Rare

Ankle, knee, or great toe joint pain

bloated

change or loss of taste

depression

difficulty having a bowel movement (stool)

dry skin

excess air or gas in the stomach or intestines

full feeling

hair loss or thinning of the hair

hearing loss

increased sensitivity of the skin to sunlight

loss of appetite

passing gas

redness or other discoloration of the skin

severe sunburn

weight loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.

Dizziness or lightheadedness may occur after the first dose of this medicine, especially if you have been taking a diuretic (water pill). Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

Check with your doctor right away if you become sick while taking this medicine, especially if you have severe or continuing nausea, vomiting, or diarrhea that does not stop. These conditions may cause you to lose too much water and may lead to low blood pressure. You can also lose water by sweating, so drink plenty of water during exercise or in hot weather.

Ask your doctor before you use medicines, supplements, or salt substitutes that contain potassium.

Avoid alcoholic beverages until you have discussed their use with your doctor. Alcohol may make the low blood pressure effect worse or increase the possibility of dizziness or fainting.

Do not take other medicines unless they have been discussed with your doctor. This especially includes prescription or nonprescription (over-the-counter [OTC]) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, and herbal or vitamin supplements.