Class Name(s):

• 40:28.20 Thiazide Diuretics

Pronunciation:

• (meth i kloe thye' a zide)

Brand Name(s):

• Aquatensen^®Â¶
• Enduron^®Â¶
• Diutensen-R^® (as a combination product containing Methyclothiazide, Reserpine)¶
• Enduronyl^® (as a combination product containing Deserpidine, Methyclothiazide)¶; also available generically

WHY is this medicine prescribed?

Methyclothiazide is used to treat high blood pressure. Methyclothiazide is also used to treat edema (fluid retention; excess fluid held in body tissues) caused by various medical problems, including heart, kidney, and liver disease and to treat edema caused by using certain medications including estrogen and corticosteroids. Methyclothiazide is in a class of medications called diuretics ('water pills'). It works by causing the kidneys to get rid of unneeded water and salt from the body into the urine.

High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

HOW should this medicine be used?

Methyclothiazide comes as a tablet to take by mouth. It usually is taken once a day in the morning. Take methyclothiazide around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take methyclothiazide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Methyclothiazide controls high blood pressure and edema but does not cure these conditions. Continue to take methyclothiazide even if you feel well. Do not stop taking methyclothiazide without talking to your doctor.

Are there OTHER USES for this medication?

Methyclothiazide may also be used to treat patients with diabetes insipidus and certain electrolyte disturbances and to prevent kidney stones in patients with high levels of calcium in their blood. Talk to your doctor about the possible risks of using this medicine for your condition.

This medicine is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking methyclothiazide,

• tell your doctor and pharmacist if you are allergic to methyclothiazide, sulfonamide medications, any other medications, or any of the ingredients in methyclothiazide tablets. Ask your pharmacist or check the patient information for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while taking methyclothiazide. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• the following nonprescription products may interact with methyclothiazide: nonsteroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen (Advil, Motrin, others) and naproxen (Aleve). Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking methyclothiazide. Do not start any of these medications while taking methyclothiazide without discussing with your healthcare provider.
• tell your doctor if you have kidney disease. Your doctor may tell you not to take methyclothiazide.
• tell your doctor if you have or have ever had asthma, diabetes, gout, high cholesterol, systemic lupus erythematosus (SLE, a chronic inflammatory condition), or liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking methyclothiazide, call your doctor immediately.
• plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Methyclothiazide may make your skin sensitive to sunlight.
• you should know that methyclothiazide may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking methyclothiazide. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. Alcohol can add to these side effects.

What SPECIAL DIETARY instructions should I follow?

If your doctor prescribes a low-salt or low-sodium diet, or to eat or drink increased amounts of potassium-rich foods (e.g., bananas, prunes, raisins, and orange juice) in your diet, follow these instructions carefully.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Tell your doctor if any of these symptoms are severe or do not go away:

• frequent urination
• stomach pain
• upset stomach
• constipation
• diarrhea
• loss of appetite
• headache
• blurred vision

Some side effects can be serious. If you have any of these symptoms, call your doctor immediately or seek emergency medical treatment:

• dry mouth; thirst; nausea; vomiting; weakness, tiredness; drowsiness; restlessness; confusion; muscle weakness, pain, or cramps; fast heartbeat and other signs of dehydration and electrolyte imbalance
• yellowing of the eyes and skin
• fever
• blisters or peeling skin
• difficulty breathing or swallowing
• rash
• itching
• hives

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medicine in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly, and blood tests should be done occasionally.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking methyclothiazide.

Do not let anyone else take your medicine. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

^¶ This branded product is no longer on the market. Generic alternatives may be available.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2025. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: August 15, 2017.