Before taking hydrochlorothiazide:

• tell your doctor and pharmacist if you are allergic to hydrochlorothiazide, sulfonamide antibiotic medications, 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 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.
• 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.

If you miss a dose, 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.

hydrochlorothiazide may cause side effects. cause? 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).