Hydrochlorothiazide is a diuretic (water pill). Irbesartan is an angiotensin II receptor blocker (sometimes called an ARB blocker).

Hydrochlorothiazide and irbesartan is a combination medicine used to treat high blood pressure (hypertension).

Hydrochlorothiazide and irbesartan may also be used for purposes not listed in this medication guide.

You should not use this medicine if you are unable to urinate, or if you are allergic to sulfa drugs.

Do not use if you are pregnant. Stop using the medicine and tell your doctor right away if you become pregnant.

If you have diabetes, do not use hydrochlorothiazide and irbesartan together with any medication that contains aliskiren (a blood pressure medicine).

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may take this medicine with or without food.

Call your doctor if you have ongoing vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking this medication, which can lead to severely low blood pressure or a serious electrolyte imbalance.

Your blood pressure will need to be checked often. Your blood and urine may also be tested if you have been vomiting or are dehydrated.

If you need surgery or medical tests, tell the surgeon ahead of time that you are using hydrochlorothiazide and irbesartan.

It may take up to 4 weeks for this medication to control your blood pressure. Keep using this medicine as directed, even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Hypertension:

Initial therapy: Hydrochlorothiazide 12.5 mg-Irbesartan 150 mg orally once a day; may increase after 1 to 2 weeks.

Add-on/Replacement therapy: Hydrochlorothiazide 12.5 to 25 mg-Irbesartan 150 to 300 mg orally once a day

Maximum dose: Hydrochlorothiazide 25 mg-Irbesartan 300 mg orally once a day

Comments:
-The recommended doses in order of increasing mean effect are (hydrochlorothiazide-irbesartan): 12.5 mg-150 mg, 12.5 mg-300 mg, 25 mg-300 mg; the largest incremental effect will likely be from monotherapy to 12.5 mg-150 mg.
-Maximum antihypertensive effect is attained within 2 to 4 weeks after a change in dose.

You should not use hydrochlorothiazide and irbesartan if you are allergic to irbesartan or hydrochlorothiazide, or:

• if you are unable to urinate; or

• if you are allergic to sulfa drugs.

If you have diabetes, do not use hydrochlorothiazide and irbesartan together with any medication that contains aliskiren (a blood pressure medicine).

You may also need to avoid taking hydrochlorothiazide and irbesartan with aliskiren if you have kidney disease.

Tell your doctor if you have ever had:

• liver disease;

• congestive heart failure;

• glaucoma;

• low or high levels of potassium in your blood;

• asthma or allergies;

• high cholesterol or triglyceride levels;

• gout;

• lupus;

• diabetes; or

• an allergy to penicillin.

Do not use if you are pregnant. Stop using the medicine and tell your doctor right away if you become pregnant. Irbesartan can cause injury or death to the unborn baby if you take the medicine during your second or third trimester.

You should not breastfeed while using this medicine.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include fast or slow heartbeat, feeling light-headed, or fainting.

Hydrochlorothiazide may increase your risk of skin cancer. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors. Your doctor may want you to have skin examinations on a regular basis.

Drinking alcohol can further lower your blood pressure and may cause side effects.

Do not use potassium supplements or salt substitutes, unless your doctor has told you to.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

In rare cases, hydrochlorothiazide and irbesartan can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.

Also call your doctor at once if you have:

• eye pain, vision problems;

• a light-headed feeling, like you might pass out;

• little or no urinating;

• jaundice (yellowing of the skin or eyes);

• easy bruising, unusual bleeding; or

• signs of an electrolyte imbalance--increased thirst or urination, confusion, vomiting, constipation, muscle pain or weakness, leg cramps, bone pain, lack of energy, irregular heartbeats, tingly feeling.

Common side effects of hydrochlorothiazide and irbesartan may include:

• dizziness;

• muscle or joint pain; or

• feeling tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

If you also take cholestyramine or colestipol, take your hydrochlorothiazide and irbesartan dose 4 hours before or 4 hours after you take the other medicine.

Tell your doctor about all your other medicines, especially:

• carbamazepine;

• insulin or oral diabetes medicine;

• lithium; or

• NSAIDs (nonsteroidal anti-inflammatory drugs)--aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others.

This list is not complete. Other drugs may affect hydrochlorothiazide and irbesartan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.