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

Hydrochlorothiazide and losartan is a combination medicine used to treat high blood pressure (hypertension). It is also used to lower the risk of stroke in certain people with heart disease.

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

You should not use hydrochlorothiazide and losartan if you are unable to urinate.

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 losartan 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 are sick with vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking hydrochlorothiazide and losartan. This can lead to very low blood pressure, a serious electrolyte imbalance, or kidney failure.

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

If you have high blood pressure, keep using this medicine even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life.

Store at room temperature away from moisture, heat, and light.

Usual Adult Dose for Hypertension:

HYPERTENSION:
Hydrochlorothiazide 12.5 to 25 mg-Losartan 50 to 100 mg orally once a day

Maximum dose: Hydrochlorothiazide 25 mg-Losartan 100 mg orally once a day

Comments:
-A patient whose blood pressure is not adequately controlled with hydrochlorothiazide or losartan monotherapy may be switched to hydrochlorothiazide 12.5 mg-losartan 50 mg orally once a day.
-May increase dose if blood pressure remains uncontrolled after about 3 weeks.

Use: Treatment of hypertension. This drug is not indicated for initial therapy except when hypertension is severe enough that the benefit of achieving prompt blood pressure control exceeds the risk of initiating combination therapy.

SEVERE HYPERTENSION:
Initial treatment: Hydrochlorothiazide 12.5 mg-Losartan 50 mg orally once a day; if blood pressure remains uncontrolled after 2 to 4 weeks, may initiate maximum dose.

Maximum dose: Hydrochlorothiazide 25 mg-Losartan 100 mg orally once a day

HYPERTENSION WITH LEFT VENTRICULAR HYPERTROPHY:
Initial therapy: Losartan monotherapy; if blood pressure remains uncontrolled, may initiate this drug.

Add-on therapy: Hydrochlorothiazide 12.5 mg-Losartan 50 mg orally once a day; if blood pressure remains uncontrolled, initiate hydrochlorothiazide 12.5 mg-losartan 100 mg orally once a day, followed by hydrochlorothiazide 25 mg-losartan 100 mg orally once a day, if needed.

Use: To reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy, but there is evidence that this benefit does not apply to Black patients.

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

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

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

Tell your doctor if you have ever had:

• lupus;

• liver or kidney disease;

• asthma or allergies;

• diabetes;

• gout;

• congestive heart failure;

• glaucoma;

• low or high levels of potassium in your blood;

• high cholesterol or triglyceride levels; 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. Hydrochlorothiazide and losartan 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.

Hydrochlorothiazide and losartan is not approved for use by anyone younger than 18 years old.

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.

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 becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids.

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

Hydrochlorothiazide and losartan may cause serious side effects. Call your doctor at once if you have:

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

• irregular heartbeats;

• eye pain, vision problems;

• kidney problems--little or no urination, rapid weight gain, swelling in your hands, feet, or ankles;

• new or worsening symptoms of lupus--joint pain, and a skin rash on your cheeks or arms that worsens in sunlight; or

• signs of an electrolyte imbalance--increased thirst or urination, confusion, vomiting, constipation, muscle pain, leg cramps, irregular heartbeats, numbness or tingling, severe weakness, loss of movement, feeling jittery or unsteady.

Common side effects of hydrochlorothiazide and losartan may include:

• dizziness;

• back pain; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

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 losartan dose 4 hours before or 4 to 6 hours after you take the other medicine.

Tell your doctor about all your other medicines, especially:

• a diuretic or "water pill";

• other blood pressure medications;

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