Microzide (Hydrochlorothiazide) - Oral

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What Is Microzide?

Microzide (hydrochlorothiazide) is a prescription drug belonging to a class of medications called thiazide diuretics, also commonly called “water pills.” It is used to treat high blood pressure (hypertension) and fluid retention (edema) caused by certain conditions.

It is not exactly known how hydrochlorothiazide works, but it is thought to remove extra salt and water from the body by increasing urine flow. By doing this, hydrochlorothiazide keeps your heart from working too hard to pump blood which lowers blood pressure and reduces swelling.

Eventually, the rate at which your heart pumps blood returns to normal, and the peripheral vascular resistance is reduced, which leads to a continued decrease in blood pressure.

Microzide is available in tablet and capsule form.

Drug Facts

  • Generic Name: Hydrochlorothiazide
  • Brand Name(s): Microzide, Aquazide H, Hydrocot, Zide
  • Administration Route(s): Oral
  • Drug Availability: Prescription
  • Therapeutic Classification: Cardiovascular agent
  • Available Generically: Yes
  • Controlled Substance: N/A
  • Active Ingredient: Hydrochlorothiazide
  • Dosage Form(s): Tablet, capsule

What Is Microzide Used For?

Hydrochlorothiazide is often prescribed to treat high blood pressure.

It is also used to treat edema that is caused by:

  • Heart failure
  • Liver damage
  • Kidney problems
  • Taking other medications (e.g., corticosteroids or estrogens)

How to Take Microzide

Microzide is available as an oral tablet or capsule. These are meant to be taken by mouth. How often you take Microzide depends on what condition you are using it to treat and how your body reacts to the medication.

You can take this medication with or without food.

Storage

Store hydrochlorothiazide at a controlled room temperature, which is about 68 F to 77 F.

If traveling, always carry your medication with you. If you are flying, make sure to keep the original prescription-labeled bottle or box in your carry-on bag. Don’t leave this medication in your car, especially if the weather is very cold or hot.

How Long Does Microzide Take to Work?

Microzide will start to work within two hours of taking it. You should notice its full effects after about four hours.

What Are the Side Effects of Microzide?

This is not a complete list of side effects and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.

Like most medications, hydrochlorothiazide can cause mild or severe side effects.

Common Side Effects

The most common side effects with hydrochlorothiazide include:

  • Low blood pressure (hypotension)
  • Dizziness
  • Headache
  • Weakness
  • Tingling in your hands, feet, and legs
  • Erectile dysfunction
  • Photosensitivity

Talk to your healthcare provider or pharmacist if any of these side effects don’t go away or become more severe.

Severe Side Effects

Contact your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you have a medical emergency.

Serious side effects and their symptoms can include the following:

  • Allergic reactions with symptoms such as rash, shortness of breath, hives, or swelling of the mouth, tongue, or lips
  • Kidney failure with symptoms such as weakness, confusion, shortness of breath, chest pain, producing less urine than normal, and increased swelling in your legs, ankles, or feet
  • Skin reactions such as Stevens-Johnson syndrome with symptoms such as painful rash, skin blisters, fever, and mouth sores
  • Blurred vision

Report Side Effects

Microzide may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (1-800-332-1088).

Dosage: How Much Microzide Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For fluid retention (edema):

For oral dosage form (tablets):

  • Adults—The usual dose is 25 to 100 milligrams (mg) daily as a single or divided dose. Your doctor may want you to take this dose every other day or on 3 to 5 days each week.
  • Children—Dose is based on body weight and must be determined by your doctor.

For high blood pressure:

For oral dosage form (capsule):

  • Adults—At first, 12.5 milligrams (mg) or one capsule once a day. Your doctor may want you to take this alone or together with other blood pressure medicines. Your doctor may increase your dose as needed. However, the dose is usually not more than 50 mg per day.
  • Children—Use and dose must be determined by your doctor.

For oral dosage form (tablets):

  • Adults—At first, 25 milligrams (mg) once a day. Your doctor may increase your dose as needed and may be taken as a single dose or divided into two doses.
  • Children—Dose is based on body weight and must be determined by your doctor.

Missed Dose

If you miss a dose of Microzide, you should take the missed dose as soon as you remember. If it is almost time for the next scheduled dose, you should skip the dose you missed. Do not take extra to make up for the missed dose. Doing so can increase your risk for side effects.

Overdose: What Happens If I Take Too Much Microzide?

If you take too much Microzide, your blood pressure can drop too low. Low blood pressure can make you feel faint or dizzy.

What Happens If I Overdose on Microzide?

If you think you or someone else may have overdosed on Microzide, call a healthcare provider or the Poison Control Center (1-800-222-1222).

If someone collapses or isn't breathing after taking Microzide, call 911 immediately.

Precautions

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It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

Check with your doctor right away if you have seizures, decreased urine, drowsiness, dry mouth, excessive thirst, increased heart rate or pulse, muscle pains or cramps, nausea or vomiting, or unusual tiredness or weakness. These may be symptoms of a condition called hypokalemia or potassium loss.

Check with your doctor right away if you have blurred vision, difficulty in reading, eye pain, or any other change in vision during or after treatment. This could be a sign of a serious eye problem. Your doctor will want you to have your eyes checked by an ophthalmologist (eye doctor).

This medicine may cause some people to become dizzy. Do not drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.

Alcohol, narcotic pain relievers, or sleeping pills may cause you to feel more lightheaded, dizzy, or faint when used with this medicine. Tell your doctor if you are drinking alcohol or using pain relievers or sleeping pills.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests (eg, tests for parathyroid function) may be affected by this medicine.

This medicine may increase your risk of getting skin cancer (eg, non-melanoma skin cancer). Avoid sun exposure. Use a sunscreen when you are outdoors. Avoid sunlamps and tanning beds. Talk to your doctor if you have concerns about this risk.

Do not take other medicines unless they have been discussed with your doctor. This includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.

What Are Reasons I Shouldn’t Take Microzide?

There are a few reasons why your healthcare provider may not choose Microzide as part of your treatment plan:

  • Sulfonamide allergy: A person should not take Microzide if they are allergic to medications that contain sulfonamides.
  • Alcohol: Minimal use of alcohol has shown to potentially decrease blood pressure, but drinking too much alcohol can cause an increase in blood pressure. 
  • Pregnancy: Animal studies have not shown harmful effects to the fetus when the mother takes the drug, and there are not enough studies to indicate if this drug causes harm to the fetus during pregnancy. Talk to your healthcare provider if you are pregnant or plan to become pregnant.
  • Breastfeeding: Microzide may pass through human milk. Talk with your provider if you are breastfeeding as you may need to decide if you should stop taking Microzide or stop breastfeeding.
  • Older adults: People 65 years or older often process drugs more slowly and may need a lower dose or a different frequency. 
  • Other health conditions: In certain individuals, the body may handle Microzide differently. You should inform your healthcare provider if you have kidney problems, poor liver function, lupus, or vision problems.

What Other Medications Interact With Microzide?

Hydrochlorothiazide can interact with several kinds of drugs, including:

  • Corticosteroids (e.g., prednisone)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g., naproxen, ibuprofen)
  • Lithium
  • Diabetes medications (e.g., insulin, metformin)
  • Opioids (e.g., oxycodone, hydrocodone)
  • Other blood pressure medications
  • Certain cholesterol medications (e.g., colestipol, cholestyramine)

This list does not include all drugs that can interact with hydrochlorothiazide. Before taking hydrochlorothiazide, be sure to tell your doctor about all of the prescription medications, over-the-counter medications, vitamins, supplements, and herbs you are taking. This will help you avoid potential interactions. If you have any questions about drug interactions, speak with your doctor or pharmacist.

What Medications Are Similar?

Microzide, a thiazide diuretic, is one type of diuretic. Other types include loop and potassium sparing.

A few other commonly prescribed diuretics include:

  • Zaroxolyn (metolazone)
  • Lasix (furosemide)
  • Aldactone (spironolactone)

Zaroxolyn

Metolazone oral tablets are also part of the class of medications known as thiazide diuretics. It is often prescribed to treat high blood pressure and swelling from heart failure and kidney diseases.

Lasix

Furosemide oral tablets are part of a class of medications known as loop diuretics. It is often prescribed to treat high blood pressure and swelling caused by other conditions like kidney disease, heart failure, or liver cirrhosis. Loop diuretics help your body get rid of excess salt and water by increasing the amount of urine your body makes.

Compared with thiazide diuretics, loop diuretics may work better for someone with impaired kidney function.

Aldactone

Spironolactone oral tablets are part of a class of medications known as aldosterone antagonists, or potassium-sparing diuretics. It is often prescribed to treat high blood pressure, heart failure, excessive aldosterone secretion (hyperaldosteronism), and swelling from kidney or liver problems.

Aldosterone is a chemical made in the body that causes water retention. By blocking aldosterone, your body won’t retain the extra fluid.

Potassium-sparing diuretics may not reduce blood pressure as well as other diuretics. They may need to be used in combination with other medications when used to treat high blood pressure.

This is a list of drugs from similar classes of medication as Microzide. It is not a list of drugs recommended to take with Microzide. Ask your healthcare provider if you have any questions.

Frequently Asked Questions

  • What is Microzide used for?

    Hydrochlorothiazide is often prescribed to treat high blood pressure. It is also used to treat swelling caused by other medications, kidney problems, liver damage, or heart failure. Hydrochlorothiazide can be prescribed by itself or in combination with other medicines.

  • How do I safely stop taking Microzide?

    Hydrochlorothiazide does not cause dependency and is not known to cause withdrawal symptoms. However, abruptly stopping hydrochlorothiazide may cause a rebound effect where your blood pressure increases or you retain more water. This does not happen in every person and typically goes away after a few days, but it can be dangerous for some people. It is best to speak with your provider before you stop taking hydrochlorothiazide.

  • Microzide is a water pill. Does that mean it can cause weight loss?

    Hydrochlorothiazide is a diuretic, also known as a water pill. These medications work by removing extra water and salt from your body. Because of this, temporary weight loss due to water loss while taking this medication is possible. However, you should not take hydrochlorothiazide for weight loss as it is not approved for this use. If you have questions about body weight and hydrochlorothiazide, it is best to speak with your provider or pharmacist.

How Can I Stay Healthy While Taking Microzide?

Microzide is a safe and effective medication when used correctly. This drug is often used to treat high blood pressure and swelling.

While Microzide does have the potential for serious side effects such as allergic reactions, kidney failure, or blurred vision, the most common side effects tend to be mild. Those might include low blood pressure, headache, dizziness, or photosensitivity.

It is important to inform your healthcare provider of all of your other health conditions and any prescription medications, over-the-counter medications, vitamins, supplements, and herbs you are taking. This way, your provider can make the best decision about what drug and dose are safe and work best for you.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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5 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.
  1. Food and Drug Administration. Hydrochlorothiazide Tablets, USP. Updated May 2011.

  2. Food and Drug Administration. Microzide Capsules. Updated February 2011.

  3. Food and Drug Administration. Metolazone tablets. Updated May 2019.

  4. Food and Drug Administration. Lasix (furosemide) tablets. Updated September 2010.

  5. Food and Drug Administration. Aldactone (spironolactone) tablets. Updated January 2008.