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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Generic drug name: chlorothiazide (klor oh THYE a zide)
Brand name(s): DIURIL
GENERIC: available FAMILY: Thiazide Diuretics
Find the drug label by searching at DailyMed.

Generic drug name: chlorthalidone (klor THAL i done)
Brand name(s): HYGROTON, THALITONE
GENERIC: not available FAMILY: Thiazide Diuretics
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Generic drug name: hydrochlorothiazide (hye droe klor oh THYE a zide)
Brand name(s): MICROZIDE
GENERIC: available FAMILY: Thiazide Diuretics
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Generic drug name: methyclothiazide (meth ee kloe THYE a zide)
Brand name(s): ENDURON
GENERIC: available FAMILY: Thiazide Diuretics
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Generic drug name: metolazone (me TOLE a zone)
Brand name(s): DIULO, ZAROXOLYN
GENERIC: available FAMILY: Thiazide Diuretics
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Generic drug name: polythiazide (pol e THYE a zide)
Brand name(s): RENESE
GENERIC: available FAMILY: Thiazide Diuretics
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

Thiazides cross the placenta and expose the fetus to the drug. Hazards include fetal or newborn liver damage and bleeding as well as other adverse reactions that have occurred in adults. Because of the potential for serious adverse effects to the fetus, these drugs should not be used by pregnant women for hypertension or the normal edema of pregnancy.

Breast-feeding Warning

Thiazides are excreted in human milk. Because of the potential for serious adverse effects in nursing infants, you should not take these drugs while nursing.

Safety Warnings For This Drug [top]

Heat Stress Alert

These drugs can affect your body’s ability to adjust to heat, putting you at risk of “heat stress.” If you live alone, ask a friend to check on you several times during the day. Early signs of heat stress are dizziness, lightheadedness, faintness, and slightly high temperature. Call your doctor if you have any of these signs. Drink more fluids (water, fruit and vegetable juices) than usual—even if you’re not thirsty—unless your doctor has told you otherwise. Do not drink alcohol.

Facts About This Drug [top]

Diuretics, commonly called water pills, are used to treat high blood pressure (hypertension), congestive heart failure and other conditions in which the body holds too much fluid. The routine use of diuretics in otherwise healthy pregnant women is inappropriate and exposes the mother and fetus to unnecessary hazards.[1]

Public Citizen lists hydrochlorothiazide (ESIDRIX, HYDRODIURIL, MICROZIDE) as a Limited Use drug.

Adverse effects

All diuretics have potential adverse effects,...

Diuretics, commonly called water pills, are used to treat high blood pressure (hypertension), congestive heart failure and other conditions in which the body holds too much fluid. The routine use of diuretics in otherwise healthy pregnant women is inappropriate and exposes the mother and fetus to unnecessary hazards.[1]

Public Citizen lists hydrochlorothiazide (ESIDRIX, HYDRODIURIL, MICROZIDE) as a Limited Use drug.

Adverse effects

All diuretics have potential adverse effects, commonly including loss of potassium and sodium from the body, harmful interactions with other drugs and allergic reactions. Diuretics in this family (thiazide diuretics) are mild, with reduced risk of dizziness, falling and other potential adverse effects suffered if the body loses too much fluid. An expert on hypertension in older adults emphasized that "thiazide diuretics [such as the ones discussed on this page] are almost certainly safer than any of the other drugs available to treat hypertension."[2]

Hydrochlorothiazide can cause unpredictable adverse eye effects, resulting in temporary nearsightedness (blurred vision for faraway objects) and a type of glaucoma (increased pressure in the eye) known as acute angle-closure glaucoma. Symptoms include eye pain or a sudden decrease in visual acuity that typically occur within hours to weeks of starting the drug. Untreated glaucoma can lead to permanent vision loss. The primary treatment for these adverse effects is to stop the drug as rapidly as possible. Some patients may need prompt medical or surgical treatments if the eye pressure remains uncontrolled. Risk factors for developing glaucoma may include a history of sulfonamide or penicillin allergy.

Thiazide diuretics also are associated with an increased risk of developing gout, a type of arthritis caused by increased blood uric acid levels[3] and a small increased risk of non-melanoma skin cancer.[4],[5],[6],[7]

First-line treatment for high blood pressure

If you have high blood pressure, the best way to reduce or eliminate your need for medication is by improving your diet, losing weight, exercising, and decreasing your salt and alcohol intake. Mild hypertension can be controlled by proper nutrition and exercise. If these measures do not lower your blood pressure enough and you need medication, hydrochlorothiazide is the drug of choice, starting with a low dosage of 12.5 mg daily. It also costs less than other blood-pressure drugs.

A major study published in 2002, known as the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), found that a thiazide diuretic (chlorthalidone, 12.5 milligrams [mg] to 25 mg a day) was better at preventing heart failure in hypertensive patients older than 55 than were amlodipine (NORVASC, a calcium channel blocker), lisinopril (PRINIVIL, ZESTRIL, an angiotensin-converting enzyme inhibitor) and doxazosin (CARDURA, an alpha-blocker). Therefore, a thiazide diuretic in general is the best first-line option for treating hypertension. Beta-blockers are now considered second- or third-line alternatives when treating hypertensive diabetic patients.[8]

There is growing evidence that thiazide diuretics, such as hydrochlorothiazide, significantly decrease the rate of bone mineral loss in both men and women because they reduce the amount of calcium lost in the urine.[9] Research now suggests that thiazide diuretics may protect against hip fracture.[10]

Hydrochlorothiazide has been studied more than the other diuretics in this family, is available in a generic form, usually costs less and is just as effective as the other thiazide diuretics. If you are taking a thiazide diuretic other than hydrochlorothiazide, compare costs and then ask your doctor about switching.

If you are taking hydrochlorothiazide, you should not — in most cases — be taking more than 50 mg per day. Daily doses higher than 50 mg do not significantly improve blood pressure control and can make adverse effects worse.[11]

If your hypertension is severe and has not responded to a drug in this family, you may need a stronger drug. See the page "High Blood Pressure" for a discussion of the alternatives.

Whatever drugs you take for high blood pressure, once your blood pressure has been normal for a year or more, a cautious decrease in dose and renewed attention to nondrug treatment may be worth trying, according to The Medical Letter on Drugs and Therapeutics.[12]

An editorial in the British Medical Journal (BMJ) stated the following:

Treatment of hypertension is part of preventive medicine, and like all preventive strategies, its progress should be regularly reviewed by whoever initiates it. Many problems could be avoided by not starting antihypertensive treatment until after prolonged observation. ... Patients should no longer be told that treatment is necessarily for life: the possibility of reducing or stopping treatment should be mentioned at the outset.[13]

An article in the April 2013 issue of Worst Pills, Best Pills News discussed another BMJ study. This study suggests that an increased risk of acute kidney injury (AKI) is associated with combining nonsteroidal anti-inflammatory drugs (NSAIDs) with two antihypertensive drugs: a diuretic plus either an ACE inhibitor or an ARB. The risk was found to be highest during the first 30 days of starting an NSAID in patients who also are already taking a diuretic plus an ACE inhibitor or an ARB.

The study found that patients currently using a triple-therapy combination — a diuretic, an ACE inhibitor or an ARB, and an NSAID — have a 31% greater risk of developing AKI compared with current users of a diuretic plus an ACE inhibitor or an ARB without an NSAID.

Before You Use This Drug [top]

Do not use if you have or have had:

  • a sensitivity to sulfa drugs (sulfonamides) or thiazide drugs

Tell your doctor if you have or have had:

  • allergies to drugs
  • diabetes
  • gout
  • kidney, liver, or pancreas problems
  • lupus erythematosus
  • a salt- or sugar-restricted diet
  • pregnancy or are breast-feeding
  • high calcium in your blood
  • high cholesterol or triglycerides

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Because these drugs help you lose water, you may become dehydrated. Check with your doctor to make certain your fluid intake is adequate and appropriate especially if you have vomiting or diarrhea.
  • Stay out of the sun as much as possible, and call your doctor if you get a rash, hives, or skin reaction. These drugs can make you more sensitive to the sun.
  • These drugs may cause your body to lose potassium, an important mineral. Potassium loss is worse when there is too much salt in your diet. See the section on potassium supplementation for information on how to make sure you get enough potassium.
  • You may feel dizzy when rising from a lying or sitting position. When getting out of bed, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, stay beside the chair until you are sure that you are not dizzy.     If you plan to have any surgery, including dental, tell your doctor that you take a thiazide diuretic.
  • Do not take any other drugs without first talking to your doctor — especially nonprescription drugs for appetite control, asthma, colds, coughs, hay fever, or sinus problems.

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose. Do not take double doses.
  • Do not share your medicine with others.
  • Take the drug(s) at the same time each day.
  • Take with food or milk to avoid stomach irritation. Tablet may be crushed and mixed with food or drink.
  • If you are taking a thiazide diuretic more than once a day, try to take the last dose before 6 p.m. This will help you avoid interrupting your sleep to go to the bathroom.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

Other blood pressure lowering drugs.

Nonsteroidal anti-inflammatory drugs such as  celecoxib (CELEBREX) and ibuprofen (ADVIL, MEDIPREN, MOTRIN, NUPRIN).

ACTH, acarbose, ACTOS, ALFENTA, alfentanil, anisindione, ANSAID, aprobarbital, aspirin, AVANDAMET, AVANDIA, betamethasone, BEXTRA, bumetanide, BUMEX, BUPRENEX, buprenorphine, butabarbital, butalbital, BUTISOL SODIUM, CARDIOQUIN, CELESTONE, chlorpropamide, cholestyramine, choline magnesium trisalicylate, CLINORIL, codeine, COUMADIN, DARVON, DAYPRO, DEMADEX, DEMEROL, deslanoside, dezocine, DIABETA, DIABINESE, diclofenac, dicumarol, diflunisal, digoxin, DILAUDID, dofetilide, DOLOBID, DOLOPHINE HCL, DURAGESIC, ESKALITH, etodolac, FELDENE, fenoprofen, fentanyl, FIORICET, flurbiprofen, furosemide, glimepiride, glipizide, GLUCOPHAGE, GLUCOTROL XL, glyburide, GLYSET, guanethidine, HYDROCET, hydrocodone, hydromorphone, INDOCIN, indomethacin, insulin, ISMELIN, ketoprofen, ketorolac, LANOXICAPS, LANOXIN, LASIX, LEVO-DROMORAN, levorphanol, lithium, LODINE, magnesium salicylate, meclofenamate, mefenamic acid, meloxicam, mephobarbital, mepiridine, METAGLIP, metformin, methadone, methenamine, miglitol, MIRADON, MOBIC, morphine, nabumetone, NAPROSYN, naproxen, NEMBUTAL SODIUM, NITRO-DUR, nitroglycerin, norepinephrine, ORUVAIL, oxaprozin, oxycodone, OXYCONTIN, pentobarbital, phenobarbital, pioglitazone, piroxicam, PONSTEL, PRANDIN, PRECOSE, propoxyphene, QUESTRAN, QUINIDEX, quinidine, QUINAGLUTE, RELAFEN, remifentanil, repaglinide, rofecoxib, rosiglitazone, salsalate, secobarbital, SECONAL SODIUM, sufentanil, sulindac, TIKOSYN, tolazamide, tobutamide, TOLECTIN, TOLINASE, tolmetin, TORADOL, torsemide, ULTIVA, UREX, valdecoxib, VIOXX, warfarin.

 

The drugs listed above have reported interactions with hydrochlorothiazide. Not all of these interactions may have been reported for the other thiazide diuretics listed in this section. Always ask your doctor and pharmacist about specific interactions for the thiazide diuretic you are taking.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • coughing, wheezing, or hoarseness
  • difficulty breathing
  • dry mouth or increased thirst that does not go away quickly after you take a drink
  • fever, chills
  • irregular heartbeat, chest pain
  • mood or mental changes
  • confusion, convulsions, or irritability
  • muscle cramps, pain
  • nausea, vomiting
  • unusual tiredness or weakness
  • weak pulse
  • black, tarry stools
  • blood in urine or stools
  • joint, lower back, or side pain
  • painful or difficult urination
  • skin rash or hives
  • yellow eyes or skin
  • unusual bleeding or bruising

Call your doctor if these symptoms continue:

  •   dizziness, lightheadedness
  •   diarrhea
  •   loss of appetite, upset stomach
  •   headache
  •   blurred vision or “halo” effect
  •   premature ejaculation or difficulty with erection
  •   increased sensitivity of skin to sunlight

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood pressure
  • complete blood count
  • blood levels of sodium, potassium, chloride, calcium, sugar, and uric acid
  • liver function tests
  • kidney function tests
  • cholesterol or triglyceride tests

last reviewed March 31, 2022