Hydrochlorothiazide is a "water pill" (diuretic) that increases the amount of urine you make, which causes your body to get rid of excess water. This drug is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.

This medication also reduces swelling/fluid retention (edema) which can result from conditions such as congestive heart failure, liver disease, or kidney disease. This can help to improve symptoms such as trouble breathing.

Take Hydrochlorothiazide exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results.

Your blood pressure will need to be checked often. Visit your doctor regularly.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using this medication and call your doctor at once if you have a serious side effect such as:

• dry mouth, thirst, nausea, vomiting;
• feeling weak, drowsy, restless, or light-headed;
• fast or uneven heartbeat;
• muscle pain or weakness;
• numbness or tingly feeling;
• a red, blistering, peeling skin rash; or
• Nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects may include:

• diarrhea;
• mild stomach pain;
• constipation; or
• Blurred vision.

Before using this medicine, consult your doctor or pharmacist if you have severe kidney disease (inability to make urine or anuria). Before using this medication, tell your doctor or pharmacist your medical history, especially of kidney disease, liver disease, untreated mineral imbalance (e.g., sodium, potassium), gout, and lupus.

If you have diabetes, hydrochlorothiazide may worsen control of blood glucose levels. Monitor your blood glucose levels regularly and inform your doctor of the results. This drug may reduce the potassium levels in your blood.

This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths or sunlamps. Use a sunscreen and wear protective clothing when outdoors.

Before having surgery, tell your doctor or dentist that you are taking this medication. This drug may make you dizzy or cause blurred vision; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages.

Before taking this medication, tell your doctor if you are using any of the following drugs:

• lithium;
• digoxin (Lanoxin);
• cholestyramine (Prevalite, Questran) or colestipol (Colestid);
• steroids (prednisone and others);
• other blood pressure medications;
• NSAIDs (non-steroidal anti-inflammatory drugs) such as aspirin, ibuprofen (Motrin, Advil), diclofenac (Voltaren), indomethacin, naproxen (Aleve, Naprosyn), piroxicam (Feldene), nabumetone (Relafen), etodolac (Lodine), and others; or
• Insulin or diabetes medicine taken by mouth.

If you miss a dose, take as soon as remembered; do not take if it is almost time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.

Store at room temperature between 59 and 86 degrees F (between 15 and 30 degrees C) away from moisture and sunlight. Do not store in the bathroom. Keep away from children and pets.