Hydrochlorothiazide is used alone or in combination with other medications to treat high blood pressure. Hydrochlorothiazide is used to treat edema (fluid retention; excess fluid held in body tissues) caused by various medical problems, including heart, kidney, and liver disease and to treat edema caused by using certain medications including estrogen and corticosteroids. Hydrochlorothiazide is in a class of medications called diuretics (‘water pills’). It works by causing the kidneys to get rid of unneeded water and salt from the body into the urine.

High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

Hydrochlorothiazide comes as a tablet, capsule, and solution (liquid) to take by mouth. It usually is taken once or twice a day. When used to treat edema, hydrochlorothiazide may be taken daily or only on certain days of the week. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take hydrochlorothiazide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Hydrochlorothiazide controls high blood pressure but does not cure it. Continue to take hydrochlorothiazide even if you feel well. Do not stop taking hydrochlorothiazide without talking to your doctor.

Hydrochlorothiazide may also be used to treat patients with diabetes insipidus and to prevent kidney stones in patients with high levels of calcium in their blood. Talk to your doctor about the possible risks of using this medicine for your condition.

This medicine is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking hydrochlorothiazide,

• Tell your doctor and pharmacist if you are allergic to hydrochlorothiazide, ‘sulfa drugs’, penicillin, or any other drugs.
• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: barbiturates such as phenobarbital and secobarbital (Seconal); corticosteroids such as betamethasone (Celestone), budesonide (Entocort), cortisone (Cortone), dexamethasone (Decadron, Dexpak, Dexasone, others), fludrocortisone (Florinef), hydrocortisone (Cortef, Hydrocortone), methylprednisolone (Medrol, Meprolone, others), prednisolone (Prelone, others), prednisone (Deltasone, Meticorten, Sterapred, others), and triamcinolone (Aristocort, Azmacort); corticotropin (ACTH, H.P., Acthar Gel); insulin and oral medications for diabetes; lithium (Eskalith, Lithobid); medications for high blood pressure or pain; nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin, others) and naproxen (Aleve, Naprosyn, others). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• If you are taking cholestyramine or colestipol, take them 1 hour before or 4 hours after taking hydrochlorothiazide.
• Tell your doctor if you have kidney disease. Your doctor may tell you not to take hydrochlorothiazide.
• Tell your doctor if you have or have ever had diabetes, asthma, gout, systemic lupus erythematosus (SLE, a chronic inflammatory condition), high cholesterol, or kidney or liver disease.
• Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking hydrochlorothiazide, call your doctor immediately.
• Plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Hydrochlorothiazide may make your skin sensitive to sunlight and increase your risk of a certain types of skin cancer. Your doctor will check your skin for skin cancers during your treatment with hydrochlorothiazide. Call your doctor if you notice any new skin changes or growths.
• You should know that hydrochlorothiazide may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking hydrochlorothiazide. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. Alcohol can add to these side effects.

If your doctor prescribes a low-salt or low-sodium diet, or to eat or drink increased amounts of potassium-rich foods (e.g., bananas, prunes, raisins, and orange juice) in your diet, follow these instructions carefully.

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Tell your doctor if any of these symptoms are severe or do not go away:

• Frequent urination
• Diarrhea
• Loss of appetite
• Headache
• Hair loss

If you experience any of the following symptoms, call your doctor immediately or get emergency medical treatment:

• Dry mouth; thirst; nausea; vomiting; weakness, tiredness; drowsiness; restlessness; confusion; muscle weakness, pain, or cramps; fast heartbeat and other signs of dehydration and electrolyte imbalance
• Blisters or peeling skin
• Hives
• Rash
• Itching
• Difficulty breathing or swallowing
• Fever, sore throat, chills, and other signs of infection
• Unusual bleeding or bruising
• Ongoing pain that begins in the stomach area, but may spread to the back
• Joint pain or swelling
• Changes in vision, eye pain, or swelling or redness in or around the eye

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medicine in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Do not allow the liquid or capsules to freeze.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly, and blood tests should be done occasionally.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking hydrochlorothiazide.

Do not let anyone else take your medicine. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.