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

Hydrochlorothiazide and olmesartan is a combination medicine used to treat high blood pressure (hypertension). Lowering blood pressure may lower your risk of a stroke or heart attack.

Hydrochlorothiazide and olmesartan is usually given after other blood pressure medicines did not work or have stopped working.

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

You should not use this medicine if you are unable to urinate.

Do not use if you are pregnant. Use effective birth control, and tell your doctor if you become pregnant during treatment.

If you have diabetes, do not use hydrochlorothiazide and olmesartan 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.

Your blood pressure will need to be checked often.

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.

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

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:

Hydrochlorothiazide 12.5 to 25 mg-Olmesartan 20 to 40 mg orally once a day

Comments:
-If blood pressure is not controlled by olmesartan alone, hydrochlorothiazide may be added starting with a dose of 12.5 mg once a day; if blood pressure is not controlled by hydrochlorothiazide alone, olmesartan may be added starting with a dose of 20 mg once a day.
-If large doses of hydrochlorothiazide have been used as monotherapy and volume depletion or hyponatremia is present, use caution when adding olmesartan as marked decreases in blood pressure may occur. Consider reducing the dose of hydrochlorothiazide to 12.5 mg before adding olmesartan.
-May be titrated every 2 to 4 weeks.

You should not use hydrochlorothiazide and olmesartan if you are allergic to hydrochlorothiazide or olmesartan, or if you are unable to urinate.

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

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

Tell your doctor if you have ever had:

• kidney disease;

• 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 or sulfa drugs.

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

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

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

Avoid driving or hazardous activity until you know how hydrochlorothiazide and olmesartan will affect you. Your reactions could be impaired. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

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 olmesartan 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, or dark colored urine.

Also call your doctor at once if you have:

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

• eye pain, vision problems;

• an unusual skin rash;

• easy bruising, unusual bleeding;

• jaundice (yellowing of the skin or eyes);

• kidney problems--little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath;

• low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;

• high potassium--slow or unusual heart rate, weakness, loss of movement; or

• low potassium--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common side effects include:

• nausea;

• dizziness;

• cold symptoms such as stuffy nose, sneezing, sore throat; or

• high levels of uric acid in your blood.

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 olmesartan dose 4 hours before or 4 hours after you take the other medicine.

Tell your doctor about all your other medicines, especially:

• steroids;

• any other blood pressure medications;

• 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 olmesartan, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.