Information on Hydrochlorothiazide

Hydrochlorothiazide is a prescription medication used primarily to treat high blood pressure. It can also be prescribed to treat edema (a buildup of fluid in the body), caused by congestive heart failure and severe kidney and liver disease. In more rare cases, it can be used to treat a condition called "water diabetes." Hydrochlorothiazide is a generic drug that is also available under several brand names, including Microzide, Ezide and Hydrodiuril. It's also often combined with other medicines to form other prescription medications.

How It Works

• Hydrochlorothiazide is classified as a diuretic. It works by blocking the kidneys' ability to reabsorb salt and fluids. Its action as a diuretic allows the body to produce more urine, thereby helping treat edema. It's not known how hydrochlorothiazide works to treat high blood pressure.

How To Take It

• Dosing for hydrochlorothiazide is dependent on the patient and the condition it is being used to treat. It's available in pill form and is typically taken once a day, with or without food. Because it makes the body produce more urine to eliminate fluids, patients should not take hydrochlorothiazide fewer than 4 hours before going to bed.

Side Effects

• People who take hydrochlorothiazide may experience constipation or diarrhea, nausea, loss of appetite, blurred vision, dizziness and lightheadedness as side effects of the medicine. None of these is cause for concern. However, some side effects could indicate a complication that may require medical treatment. Contact your doctor if you experience any of the following: dark or decreased urine; a fast or irregular heartbeat; increased thirst; joint pain, warmth or redness, especially in the big toe; fainting; fever, chills or sore throat; irregular or fast heartbeat; mood changes; confusion; muscle pain or cramps; jaundice; severe or persistent stomach pain or nausea; vomiting; red, swollen or peeling skin; tingling or numbness; seizures; shortness of breath; unusual fatigue; unusual dry mouth; or unusual bleeding or bruising.

Warnings

• Some medications containing hydrochlorothiazide may contain sulfites, so be sure to tell your doctor and pharmacist if you are allergic to sulfites. Hydrochlorothiazide also may not be safe for people who have kidney disease and are unable to produce urine. Diabetics should be careful when using the medication, because it can alter blood sugar levels. It can also lower blood potassium levels, so patients may need to eat a more potassium-rich diet or take a supplement.

Drug Interactions

• Hydrochlorothiazide is known to interact with several other medications. Taking it with barbiturates, corticosteroids, narcotics or corticotropin can increase the risk of experiencing hydrochlorothiazide's side effects. When taken with ketanserin, digoxin or dofetilide, the risk of developing an irregular heartbeat is increased. Hydrochlorothiazide may not be as effective when taken with nonsteroidal anti-inflammatory drugs, colestipol and cholestryamine. Insulin and diabetes drugs also may not be as effective when taken with hydrochlorothiazide.