Heart Health High Blood Pressure Treatment What to Know About Microzide (Hydrochlorothiazide) This medication is used to treat the buildup of fluid in the body By Brittany Ferri Brittany Ferri LinkedIn Brittany Ferri, MS, OTR-L, CCTP, is an occupational therapist, consultant, and author specializing in psychosocial rehab. Learn about our editorial process Medically reviewed by Richard N. Fogoros, MD Medically reviewed by Richard N. Fogoros, MD on October 11, 2019 Facebook LinkedIn Richard N. Fogoros, MD, is a retired professor of medicine and board-certified internal medicine physician and cardiologist. Learn about our Medical Review Board on October 11, 2019 Print Table of Contents View All Table of Contents Uses Before Taking Dosage Side Effects Warnings and Interactions Hydrochlorothiazide is a prescription diuretic, more commonly known as a "water pill," used to help the body eliminate extra sodium through urine. This excess sodium may be building up due to high blood pressure, heart failure, chronic kidney disease, liver disease, or inflammatory conditions of the body. The most common brand name version of hydrochlorothiazide is Microzide. However, other brand names forms of hydrochlorothiazide include Zide, Aquazide, Thiazide, and Hydrocot. Hero Images / Getty Images Uses Hydrochlorothiazide is a Food and Drug Administration (FDA) approved drug for the use in treating edema or fluid buildup associated with congestive heart failure, cirrhosis of the liver, and therapies such as synthetic corticosteroids and estrogen. Other FDA-approved uses for hydrochlorothiazide include treating edema, or swelling, associated with chronic kidney failure, nephrotic syndrome, and high blood pressure. Hydrochlorothiazide can be used as the primary treatment for hypertension, or it can supplement other blood pressure medication for those with severe hypertension. Off-Label Uses Hydrochlorothiazide has been approved to treat edema, which may result in some late-stage kidney diseases. One of the most popular off-label uses for hydrochlorothiazide is to prevent recurrent calcium nephrolithiasis, more commonly known as kidney stones. When taken on a regular basis, hydrochlorothiazide effectively regulates the urine levels of calcium in patients who frequently develop kidney stones. Another off label-use for hydrochlorothiazide is for the treatment of lithium-induced diabetes insipidus. Diabetes insipidus is a condition that develops from an imbalance of bodily fluids. These bodily fluids begin to accumulate in response to inadequate production of antidiuretic hormones in the brain. A hormone change such as this can be triggered by heightened blood levels of the medication lithium. Though effective in treating conditions such as bipolar disorder, lithium has harmful side effects when levels are even slightly higher than normal. While hydrochlorothiazide assists in regulating fluid levels which result from lithium-induced diabetes insipidus, this medication does not address the root cause of the disease. Lithium-induced diabetes insipidus should be properly addressed by balancing and maintaining levels of lithium in the bloodstream. Before Taking A patient should undergo a thorough medical history and evaluation before being prescribed hydrochlorothiazide. This will ensure the patient does not have any underlying medical conditions or interacting prescription medications which will cause unsafe or harmful side effects. Hydrochlorothiazide is relatively safe to prescribe and is often considered a first-line of treatment due to its effectiveness in redistributing fluid buildup. Precautions and Contraindications Hydrochlorothiazide should not be taken by women who are pregnant and have an edema-related condition causing fluid buildup. Taking hydrochlorothiazide for this purpose may cause a redistribution of vital fluids in the body, placing a fetus at risk for injury. However, hydrochlorothiazide can be taken by pregnant women experiencing fluid buildup as a result of their pregnancy. This medication should not be taken by pregnant women at risk for developing toxemia, as this drug is not approved for the prevention of toxemia. It also should not be taken by individuals with sensitivities to the drug or other sulfonamide-based drugs. Hydrochlorothiazide should not be taken by individuals with anuria, also known as the inability of the kidneys to produce urine. All patients taking hydrochlorothiazide should be closely monitored to prevent electrolyte imbalance, especially if the patient frequently vomits as a result of the medication. This may come in the form of hyponatremia, hypochloremic alkalosis, and hypokalemia. Signs of electrolyte imbalance may include: Dry mouth and excessive thirst Increased fatigue Muscle weakness Confusion Low blood pressure Low heart rate Muscle cramps Low urine output Nausea and vomiting When under observation for electrolyte imbalance, patients should also be monitored for severe complications such as cardiac arrhythmia. If urine output is increased as a result of hydrochlorothiazide, it may also increase the urinary output of magnesium. This can cause the body to enter a state of hypomagnesemia. Hyperglycemia may occur in patients who take hydrochlorothiazide. For this reason, patients with diabetes may require adjustments to their doses of insulin. Other Diuretics Loop-acting diuretic: This type of drug lowers the amount of water in the body and increases urine output. Examples of these drugs are Bumex, Demadex, Edecrin, and Lasix. Potassium-sparing diuretic: This type of drug helps the body retain potassium while shedding the fluid buildup. Examples of these drugs are Aldactone, Dyrenium, and Midamor. What You Need to Know About Diuretics Dosage Hydrochlorothiazide is available in 12.5 milligrams (mg), 25 mg, and 50 mg tablets. It is typically recommended adults with edema take 25 mg to 100 mg of hydrochlorothiazide daily. Adults with high blood pressure should take 25 mg of hydrochlorothiazide daily. Doses for high blood pressure may be increased to 50 mg daily if the patient tolerates the starting dose. Patients who take more than 50 mg daily of hydrochlorothiazide are at risk for significantly lowered potassium levels. All listed dosages are according to the drug manufacturer. Check your prescription and talk to your doctor to make sure you are taking the right dose for you. When given to older patients, doses of hydrochlorothiazide are typically 12.5 mg once daily. When prescribed for infants, hydrochlorothiazide is typically taken according to weight. A dose of 0.5 mg to 1 mg per pound per day is the standard formula. Caution should be taken to ensure doses do not exceed 37.5 mg per day for infants up to 2 years old, and 100 mg per day for children 2 to 12 years old. For infants less than 6 months old, doses are typically 1.5 mg per pound per day. Doses often must be split into two for these infants less than 6 months old to ensure the drug is adequately tolerated. How to Take and Store Hydrochlorothiazide is slightly less effective when taken with food. This drug should be taken as per your doctor’s instruction in accordance with your tolerance to its effects. Hydrochlorothiazide should be stored in a room between 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit). Side Effects As with all medications, hydrochlorothiazide may cause side effects. Common Common side effects which may result from taking hydrochlorothiazide include: Muscle spasms Muscle weakness Diarrhea Vomiting Constipation Gastrointestinal discomfort Impotence Rash Fever Minor electrolyte imbalance Dizziness Headache Restlessness Severe Severe side effects which may result from taking hydrochlorothiazide include: Orthostatic hypotension (especially when combined with sedative drugs or alcohol) Pancreatitis Jaundice Anorexia Aplastic anemia Leukopenia (low white blood cells) or agranulocytosis (severe low white blood cell count) Thrombocytopenia (low platelet count) Anaphylactic reactions Respiratory distress Renal failure or renal dysfunction Blurred vision If renal failure or renal dysfunction of any kind develops, this drug should be discontinued immediately and emergency services should be sought to address its effects. Warnings and Interactions Hydrochlorothiazide interacts with the following prescription drugs: Barbiturates Narcotics Antidiabetic drugs Antihypertensive drugs Colestipol resins for gastrointestinal disorders Corticosteroids for inflammation Muscle relaxers Lithium for mood disorders Non-steroidal anti-inflammatory drugs (NSAIDs) for over-the-counter pain relief Hydrochlorothiazide can also interact with laboratory tests for parathyroid function, meaning the drug should be discontinued before drawing the blood for this test. A black box warning is attached to hydrochlorothiazide due to its ability to cause fetal mortality in women using the drug to treat high blood pressure. Was this page helpful? Thanks for your feedback! Looking to start a diet to better manage your high blood pressure? Our nutrition guide can help. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Microzide capsules. U.S. Food and Drug Administration. Published February 2011. Hydrochlorothiazide tablets, USP. U.S. Food and Drug Administration. Published May 2011. Diuretic drug therapy. Smidt Heart Institute. Published February 2019. Hydrochlorothiazide side effects. Drugs.com. Published February 13, 2019.