This medication is used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Methyclothiazide is a "water pill" (diuretic) that causes your body to get rid of extra salt and water. This increases the amount of urine you make.
This medication also reduces extra fluid in the body (edema) caused by conditions such as congestive heart failure, liver disease, and kidney disease. Getting rid of extra water helps to reduce fluid in the lungs so that you can breathe easier. It also helps to decrease swelling of the arms, legs, and stomach/abdomen.
OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.
This medication may also be used to treat a condition known as "water diabetes" (diabetes insipidus) and to help prevent calcium kidney stones.
Take this medication by mouth with or without food, usually once daily or as directed by your doctor. It is best to avoid taking this medication within 4 hours of your bedtime to avoid having to get up to urinate. Consult your doctor or pharmacist if you have questions about your dosing schedule.
The dosage is based on your medical condition and response to therapy. The manufacturer recommends that you do not take more than 10 milligrams as a single daily dose to treat edema or more than 5 milligrams daily to treat high blood pressure.
Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day or as prescribed. Do not increase your dose, skip doses, or stop taking this medication unless directed by your doctor. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick. For the treatment of high blood pressure, it may take up to several weeks before the full benefit of this drug takes effect.
Cholestyramine and colestipol can decrease the absorption of this medication by your body. If you are taking either of these drugs, separate them from methyclothiazide by at least 4 hours.
Inform your doctor if your condition does not improve or if it worsens (e.g., swelling increases, your routine blood pressure readings increase).
Dizziness, lightheadedness, headache, blurred vision, loss of appetite, stomach upset, diarrhea, or constipation may occur as your body adjusts to the medication. You may also experience decreased sexual ability or increased sensitivity to the sun. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may cause a loss of too much body water (dehydration) and salt/minerals. Tell your doctor immediately if you have any of these unlikely but serious symptoms of dehydration or mineral loss: very dry mouth, thirst, muscle cramps, weakness, fast/irregular heartbeat, nausea, vomiting, severe dizziness, unusual drowsiness, unusual decrease in the amount of urine, fainting, confusion, seizures.
Tell your doctor immediately if any of these unlikely but serious side effects occur: numbness/tingling of the arms/legs, joint pain (e.g., big toe pain).
Tell your doctor immediately if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding, stomach/abdominal pain, persistent nausea/vomiting, unusual/persistent tiredness, yellowing eyes/skin, dark urine, unusual change in the amount of urine (not including the normal increase in urine when you first start this drug).
Get medical help right away if you have any very serious side effects, including: decrease in vision, eye pain.
A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking methyclothiazide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: severe kidney disease (inability to make urine).
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, untreated salt/mineral imbalance (e.g., imbalance of sodium, potassium, calcium, magnesium), loss of too much body water (dehydration), gout, lupus, certain recent nerve surgery (sympathectomy).
If you have diabetes, methyclothiazide may affect your blood sugar levels. Check your blood sugar levels regularly as directed and share the results with your doctor. Tell your doctor immediately if you have symptoms of high blood sugar such as increased thirst/urination. Your doctor may need to adjust your anti-diabetic medication or diet.
This drug may reduce the potassium levels in your blood. Ask your doctor about increasing the amount of potassium in your diet (e.g., bananas, orange juice) or about using a salt substitute containing potassium. A potassium supplement may be prescribed by your doctor.
This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths, and sunlamps. Use a sunscreen and wear protective clothing when outdoors.
Before having surgery, tell your doctor or dentist that you are taking this medication.
This drug may make you dizzy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. Significant loss of body water from too much sweating, vomiting, or diarrhea can also lower your blood pressure and worsen dizziness. Drink plenty of fluids to prevent these effects and dehydration. If you are on restricted fluid intake, consult your doctor for further instructions. Contact your doctor if you are unable to drink fluids or if you have persistent diarrhea/vomiting.
Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, the elderly may be more sensitive to the effects of this drug, especially dizziness.
This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.
This drug passes into breast milk. While there have been no reports of harm to nursing infants, consult your doctor before breast-feeding.
See also the How to Use section.
Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
This drug should not be used with the following medications because very serious interactions may occur: cisapride, dofetilide.
If you are currently using any of these medications, tell your doctor or pharmacist before starting methyclothiazide.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: diazoxide, digoxin, lithium, nonsteroidal anti-inflammatory drugs (e.g., ibuprofen, indomethacin), drugs that can increase dizziness (e.g., phenobarbital, narcotic pain relievers such as codeine).
Check the labels on all your medicines (e.g., cough-and-cold products, diet aids, nonsteroidal anti-inflammatory drugs-NSAIDs for pain/fever reduction) because they may contain ingredients that could increase your blood pressure (e.g., pseudoephedrine, phenylephrine) or reduce the effect of this medication (e.g., ibuprofen, naproxen). Ask your pharmacist about the safe use of those products.
This product can affect the results of certain lab tests. Make sure laboratory personnel and all your doctors know you use this drug.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe dizziness, severe weakness, fainting.
Do not share this medication with others.
Lifestyle changes such as stress reduction programs, exercise, and dietary changes may increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.
Laboratory and/or medical tests (e.g., blood mineral levels such as potassium, kidney and liver function tests) should be performed from time to time to monitor your progress or check for side effects. Consult your doctor for more details.
Have your blood pressure checked regularly while taking this medication. Learn how to monitor your own blood pressure, and share the readings with your doctor.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store in a tightly closed container at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised November 2014. Copyright(c) 2014 First Databank, Inc.
With WebMD's Medicine Cabinet, you can check interactions with drugs.Go to medicine cabinet