In the U.S.—

• Antihypertensive

Irbesartan ( ir-be-SAR-tan) belongs to the class of medicines called angiotensin II inhibitor antihypertensives. It is used 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. High blood pressure also may increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Irbesartan works by blocking the action of a substance in the body that causes blood vessels to tighten. As a result, irbesartan relaxes blood vessels. This lowers blood pressure.

This medicine is available only with your doctor's prescription, in the following dosage form(s):

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For irbesartan, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to irbesartan. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Use of irbesartan during pregnancy, especially during the second and third trimesters (after the first 3 months), can cause low blood pressure, severe kidney failure, or even death in the newborn. Therefore, it is important that you check with your doctor immediately if you think that you may have become pregnant. Be sure that you have discussed this with your doctor before taking this medicine.

Breast-feeding—It is not known whether irbesartan passes into breast milk. However, irbesartan passes into the milk of lactating rats. Because this medicine may cause serious side effects, breast-feeding is generally not recommended while you are taking it.

Children—This medicine has been tested in children over 6 years of age and has not been shown to cause different side effects or problems than it does in adults.

Older adults—This medicine has been tested in patients 65 years of age or older and has not been shown to cause different side effects or problems in older people than it does in younger adults. However, blood levels of irbesartan may be increased in the elderly and elderly patients may be more sensitive to the effects of irbesartan.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking irbesartan, it is especially important that your health care professional know if you are taking any of the following:

• Diuretics (water pills)—Effects on blood pressure may be increased

• Congestive heart failure, severe—Lowering of blood pressure by irbesartan may make this condition worse

• Dehydration—Blood pressure–lowering effects of irbesartan may be increased.

• Kidney disease—Effects of irbesartan may be increased because of slower removal of medicine from the body.

Take this medicine only as directed by your doctor. Do not take more of it and do not take it more often than your doctor ordered. This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at the same time each day.

Dosing—

The dose of irbesartan will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of irbesartan. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

• For oral dosage form (tablets):
  • For high blood pressure:
    • Adults and adolescents over 13 years of age—150 milligrams (mg) once a day. Your doctor may increase your dose if needed.
    • Children 6 to 12 years of age—75 mg once a day. Your doctor may increase your dose if needed.
    • Children under 6 years of age—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Check with your doctor immediately if you think that you may be pregnant. Irbesartan may cause birth defects or other problems in the baby if taken during pregnancy.

Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.

Dizziness or light-headedness may occur, 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 experience these effects.

Check with your doctor right away if you become sick while taking this medicine, especially with severe or continuing nausea and vomiting or diarrhea. These conditions may cause you to lose too much water and lead to low blood pressure.

Dizziness, lightheadedness, or fainting may also occur if you exercise or if the weather is hot. Heavy sweating can cause loss of too much water and result in low blood pressure. Use extra care during exercise or hot weather.

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 as soon as possible if any of the following side effects occur:

• Rare
  • Dizziness, lightheadedness, or fainting 
  
  

• Frequency not determined
  • Confusion, irregular heartbeat, numbness or tingling in hands, feet, or lips, shortness of breath, difficult breathing , or weakness or heaviness of legs;  clay-colored stools, dark urine, itching, loss of appetite, stomach pain, or yellow eyes or skin;  large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet or sex organs 
  
  

  Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

  • Less common
    • Anxiety and/or nervousness;  cold-like symptoms;  belching, heartburn, and stomach discomfort ;  cold symptoms;  diarrhea ;  headache;  muscle or bone pain;  unusual tiredness 
    
    

• Frequency not determined
  • Hives or welts, itching, redness of skin, or skin rash 
  
  

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