Methyclothiazide | Side Effects, Dosage, Uses & More
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Generic Name:

methyclothiazide, Oral tablet

All Brands

  • Enduron (Discontinued)
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
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Highlights for methyclothiazide

Oral tablet
1

Methyclothiazide is an oral drug that’s used to treat high blood pressure. It’s also used to treat fluid buildup (edema) caused by heart failure or other conditions.

2

For high blood pressure, the standard dose ranges from 2.5–5 mg taken by mouth once per day. For edema, the usual dose is between 2.5–10 mg taken once per day.

3

This drug is a water pill (diuretic) that helps your body get rid of excess water by increasing your amount of urine. If you take too much, it can cause dangerously low levels of electrolytes in your body.

4

Since this medicine will make you urinate more often, try to take it earlier in the day. This will keep you from needing to go to the bathroom in the middle of the night.

5

Common side effects include headache, dizziness, muscle cramping, weakness, and more.

IMPORTANT INFORMATION

Low electrolytes

This drug may cause you to lose too much fluids and electrolytes. This can lead to low blood pressure, especially when you stand up from a sitting or lying position, and low potassium levels. Standing up slowly, taking potassium supplements, and changing your diet can help with these symptoms. Talk to your doctor.

Alcohol

Drinking alcohol while taking methyclothiazide may increase your chance of a severe drop in low blood pressure. You may feel dizzy, lightheaded, or faint.

What is methyclothiazide?

Methyclothiazide is a prescription drug. It’s available as an oral tablet.

Methyclothiazide is only available as a generic drug.

Methyclothiazide may be taken as part of a combination therapy with other blood pressure medications.

Why it's used

Methyclothiazide is used to treat high blood pressure. It’s also given to treat swelling due to fluid buildup (edema) that’s caused by other medical conditions.

How it works

Methyclothiazide belongs to a class of drugs called thiazide diuretics. A class of drugs is a group of medications that work in a similar way. They are often used to treat similar conditions.

More Details

How it works

Methyclothiazide belongs to a class of drugs called thiazide diuretics. A class of drugs is a group of medications that work in a similar way. They are often used to treat similar conditions. 

This drug works in your kidneys to remove excess sodium (salt) and water from your body. This helps reduce your blood pressure and swelling due to water retention.

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methyclothiazide Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with methyclothiazide include:

  • headache

  • dizziness

  • muscle cramping

  • weakness

  • low blood pressure that causes you to feel dizzy or lightheaded when standing up quickly from a sitting or lying position (orthostatic hypotension)

  • upset stomach

  • decreased appetite

  • nausea

  • vomiting

  • diarrhea

  • constipation

  • muscle spasms

  • restlessness

  • blurry vision

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have any of these serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency.

  •  fluid and electrolyte imbalance. Symptoms include:

    • dry mouth
    • thirst
    • weakness
    • tiredness
    • drowsiness
    • restlessness
    • muscle pains or cramps
    • severe nausea
    • severe vomiting
    • fast heart rate
  • inflammation of your pancreas (pancreatitis). Symptoms include:

    • stomach pain, especially after eating, that may go around to your back
    • fever
    • severe nausea
    • severe vomiting
  • blood disorders. Methyclothiazide may decrease your red blood cells, white blood cells, and platelets.

    • low red blood cells (anemia). Symptoms include:
      • feeling very tired or lightheaded
      • shortness of breath
      • pale skin
    • low white blood cells (infections). Symptoms include:
      • fever
      • cold symptoms that don’t go away, such as a runny nose or sore throat
      • flu symptoms, such as body aches or tiredness
    • low platelets (bleeding). Symptoms include:
      • cuts or wounds that don’t stop bleeding
  • allergic reactions. Symptoms include:

    • swelling of your face, lips, tongue, or throat
    • trouble swallowing or breathing
    • fever
    • red, painful, or itchy rash
    • blistering or peeling skin
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Methyclothiazide may cause dizziness.

You’ll have to urinate more often shortly after taking methyclothiazide.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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methyclothiazide May Interact with Other Medications

Oral tablet

Methyclothiazide can interact with other medications, herbs, or vitamins you might be taking. An interaction is when a substance changes the way a drug works. This can be harmful or cause the drugs that you take to not work as well. To help prevent interactions, your doctor should manage all of your medications carefully. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Alcohol interaction

The use of drinks that contain alcohol can increase your risk of a sudden drop in blood pressure from methyclothiazide. You may feel dizzy, lightheaded, or faint, especially when you stand up from a sitting or lying position. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Barbiturates or narcotics

Taking these drugs with methyclothiazide may increase your risk of very low blood pressure, especially when standing up from a sitting or lying position (orthostatic hypotension).

These drugs include:

  • barbiturates, such as:
    • amobarbital
    • butabarbital
    • pentobarbital
    • phenobarbital
    • secobarbital
  • narcotics, such as:
    • codeine
    • hydrocodone
    • morphine
    • oxycodone

Heart drugs

If you have low blood potassium levels (hypokalemia), you may be more sensitive to the side effects of this medication when taken with methyclothiazide. You may have an irregular heart rate.

These drugs include:

  • digoxin

Corticosteroids

When taken together with methyclothiazide, corticosteroids can decrease levels of potassium in your body (hypokalemia).

These drugs include:

  • betamethasone
  • budesonide
  • dexamethasone
  • hydrocortisone
  • methylprednisolone
  • prednisolone
  • prednisone

Diabetes drugs

Methyclothiazide may raise your blood sugar (hyperglycemia). If you have diabetes, you may need to test your blood sugar more often. Your doctor may need to change your diabetes medications.

These drugs include:

  • insulin

Bipolar disorder and mania drugs

Methyclothiazide can increase the amount of these medications in your body. This can cause dangerous side effects.

These drugs include:

  • lithium

Muscle disorder drugs

You may be more sensitive to this medication’s effects when you take it with methyclothiazide.

These drugs include:

  • skeletal muscle relaxants, such as:
    • tubocurarine

Blood pressure drugs

Taking methyclothiazide with these medications can cause your blood pressure to drop to a dangerously low level. You may feel dizzy, lightheaded, or faint.

These drugs include:

  • antiadrenergic blockers, such as:
    • doxazosin
    • prazosin
    • reserpine
    • terazosin

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Methyclothiazide warnings
liver problems
People with liver problems

This drug may cause a fluid and electrolyte imbalance in your body. This can lead to other severe liver problems that need immediate medical attention. Let your doctor know if you have any liver problems.

kidney problems
People with kidney problems

If you have kidney problems, talk to your doctor about whether this drug is safe for you. Your doctor will monitor you closely. Methyclothiazide may make kidney problems worse.

urination problems
People with urination problems

If you don’t make any urine (anuria), you shouldn’t take this drug.

lupus
People with lupus

Methyclothiazide may worsen or activate lupus.

sulfa allergy
People with a sulfa allergy

Methyclothiazide is chemically similar to a class of medications called sulfonamides (sulfa drugs). If you’re allergic to sulfa medications, you may be allergic to methyclothiazide. You shouldn’t take this drug if you have a sulfa allergy.

breathing problems
People with breathing problems

If you have breathing problems, such as asthma, you’re more likely to have an allergic reaction when you take methyclothiazide. Tell your doctor about any breathing problems that you have before starting this medication.

diabetes
People with diabetes

Methyclothiazide may raise your blood sugar (hyperglycemia). You may need to test your blood sugar more often. Your doctor may change the medications you take to control your diabetes.

gout
People with gout

Methyclothiazide may increase uric acid levels and cause a gout attack. Tell your doctor if you have a history of gout attacks. They will monitor your uric acid levels.

blood disorders
People with blood disorders

If you have a history of low red blood cells, white blood cells, or platelets, tell your doctor. Methyclothiazide may decrease these levels even further in some people. This puts you at risk for anemia, infections, or bleeding.

heart failure
People with heart failure

Methyclothiazide may cause you to develop kidney problems and you may need to stop taking this drug. Symptoms include changes in the amount you urinate, swelling in your feet or ankles, and confusion.

pregnant women
Pregnant women

Methyclothiazide is a pregnancy category B drug. That means two things:

  1. Studies of the drug in pregnant animals have not shown risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show the drug poses a risk to the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. Animal studies do not always predict the way humans would respond. Therefore, this drug should only be used in pregnancy if clearly needed.

breastfeeding
Women who are breast-feeding

Methyclothiazide may pass into breast milk and may cause side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your baby. You may need to decide whether to stop breast-feeding or stop taking this medication.

for seniors
For seniors

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

for children
For children

This medicine hasn’t been studied in children and shouldn’t be used in children younger than 18 years.

allergies
Allergies

Methyclothiazide may cause a serious allergic reaction. Symptoms include:

  • itching and hives
  • feelings of warmth and reddening of your face (flushing) 
  • swelling of your throat or tongue
  • wheezing or trouble breathing
  • an odd feeling in your chest or a fast heart rate
  • nausea, vomiting, or diarrhea
  • dizziness or fainting

Call 9-1-1 or go to the nearest emergency room if you develop these symptoms.

Don’t take this drug again if you’ve ever had an allergic reaction to it or other sulfa drugs before. Taking it again could be fatal (cause death).

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How to Take methyclothiazide (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your doctor will tell you what dosage is right for you. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

High blood pressure (hypertension)

Generic: methyclothiazide

Form: Oral tablet
Strengths: 5 mg
Adult dosage (ages 18–64 years)
  • Standard doses range from 2.5–5 mg taken by mouth once per day.
  • Your doctor may adjust your dose depending on how you respond to the drug.
  • If your blood pressure is still not controlled after 8–12 weeks, your doctor may add a different blood pressure medication.
Child dosage (ages 0–17 years)

This medicine hasn’t been studied in children and shouldn’t be used in children younger than 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Methyclothiazide comes with serious risks if you don't take it as prescribed.

If you don't take it at all

If you have high blood pressure and don’t take this drug, your blood pressure will stay high. This will raise your risk of a heart attack or stroke.

If you have swelling and don’t take this drug, your swelling won’t be controlled. This can lead to pain, infections, leg ulcers, and blood clots.

If you stop taking it suddenly

If you stop taking this drug, your blood pressure won’t be controlled. This will you raise your risk of having a heart attack or stroke.

If you don't take it on schedule

If you don’t take this drug on schedule, your blood pressure may not be controlled or your swelling may not get better.

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours until the time for your next dose, then wait and only take one dose at that time.

Never try to catch up by taking two doses at once. This could cause toxic side effects.

If you take too much

If you take too much of methyclothiazide, you may have too little potassium in your blood. This may cause the following symptoms:

  • confusion
  • dizziness
  • weakness in your muscles
  • upset stomach

If you think you’ve taken too much of the drug, act right away. Call your doctor or local Poison Control Center, or go to the nearest emergency room.

How to tell this drug is working

If you’re taking this drug for high blood pressure, you may be able to tell this drug is working if you check your blood pressure and it’s lower. Your doctor will also monitor your blood pressure.

If you’re taking this drug for swelling, you may be able to tell if this drug is working if your swelling decreases.

Methyclothiazide is used for long-term treatment.

Important considerations for taking methyclothiazide

Take this drug earlier in the day

Since this medication will make you urinate more often, try to take it earlier in the day. This will keep you from needing to go to the bathroom in the middle of the night.

Store methyclothiazide carefully

  • Store methyclothiazide at room temperature between 68°F (20°C) and 78°F (25°C).
  • Keep this drug away from light.
  • Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.
  • Don’t freeze methyclothiazide.
  • Keep it away from high temperature.

Travel

When traveling with your medication:

  • Always carry it with you or in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport security staff the pharmacy prescription label for your medication. Be sure to carry with you the box your medication came in, which has this label.
  • Don’t leave this medicine in the car, especially when the temperature is hot or freezing.

Self-management

You may need to check your blood pressure at home. You should keep a log with the date, time of day, and your blood pressure readings. Bring this diary with you to your doctor appointments.

Your doctor may ask you to purchase a blood pressure monitor to check your blood pressure between office visits.

Clinical monitoring

During treatment with this drug, your doctor will check your:

  • blood pressure
  • kidney function
  • liver function
  • electrolyte levels, such as blood potassium levels
  • blood cell counts

Sun sensitivity

Methyclothiazide can make you more sensitive to the sun’s effects. You should:

  • avoid being in direct sunlight for long periods of time.
  • wear protective clothing that covers most areas of your body.
  • use sunscreen whenever you’re outside.

Hidden costs

You may need to purchase a home blood pressure monitor to keep track of your blood pressure. These are available at most pharmacies.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other options that may work for you.

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How Much Does methyclothiazide Cost?

Oral tablet

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Lowest price for methyclothiazide

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These prices represent the lowest priced national pharmacies for methyclothiazide on GoodRx. They may be lower than your insurance.

Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on September 21, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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