Metolazone

Generic name: metolazone
Brand names: Zaroxolyn, Mykrox
Dosage form: oral tablet (10 mg; 2.5 mg; 5 mg)
Drug class: Thiazide diuretics

Medically reviewed by A Ras MD.

What is metolazone used for?

Metolazone is a prescription medicine that is used to treat high blood pressure. It is used to get rid of extra fluid.

Description

Metolazone tablets, USP, for oral administration contain 2½, 5, or 10 mg of metolazone, USP, a diuretic/saluretic/antihypertensive drug of the quinazoline class.

Metolazone has the molecular formula C 16H 16ClN 3O 3S, the chemical name 7-chloro-1, 2, 3, 4-tetrahydro-2-methyl-3-(2-methylphenyl)-4-oxo-6-quinazolinesulfonamide, and a molecular weight of 365.83. The structural formula is:

Metolazone is only sparingly soluble in water, but more soluble in plasma, blood, alkali, and organic solvents.

Inactive Ingredients: Magnesium stearate, microcrystalline cellulose, Colloidal silicon Dioxide and dye: 10 mg- D & C Yellow 10 Aluminum Lake.

Before taking metolazone, tell your doctor:

If you are allergic to metolazone; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
If you are not able to pass urine.
If you have liver disease.
If you are taking lithium.

This is not a list of all drugs or health problems that interact with metolazone.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take metolazone with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take metolazone?

Tell all of your health care providers that you take metolazone. This includes your doctors, nurses, pharmacists, and dentists.
Avoid driving and doing other tasks or actions that call for you to be alert until you see how metolazone affects you.
To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down. Be careful going up and down stairs.
If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
Check your blood pressure as you have been told.
Have blood work checked as you have been told by the doctor. Talk with the doctor.
If you are taking metolazone and have high blood pressure, talk with your doctor before using OTC products that may raise blood pressure. These include cough or cold drugs, diet pills, stimulants, ibuprofen or like products, and some natural products or aids.
This medicine is a strong fluid-lowering drug (diuretic). Sometimes too much water and electrolytes (like potassium) in the blood may be lost. This can lead to severe health problems. Your doctor will follow you closely to change the dose to match your body’s needs.
You may need extra potassium. Talk with your doctor.
If you are on a low-salt or salt-free diet, talk with your doctor.
Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
Watch for gout attacks.
If you have lupus, metolazone can make your lupus active or get worse. Tell your doctor right away if you get any new or worse signs.
This medicine may make you sunburn more easily. Use care if you will be in the sun. Tell your doctor if you sunburn easily while taking metolazone.
Use with care in children. Talk with the doctor.
Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

How is metolazone best taken?

Use metolazone as ordered by your doctor. Read all information given to you. Follow all instructions closely.

This medicine may cause you to pass urine more often. To keep from having sleep problems, try not to take too close to bedtime.
Keep taking metolazone as you have been told by your doctor or other health care provider, even if you feel well.

What do I do if I miss a dose?

Take a missed dose as soon as you think about it.
If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
Do not take 2 doses at the same time or extra doses.

What are the side effects of metolazone that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
Signs of fluid and electrolyte problems like mood changes, confusion, muscle pain or weakness, a heartbeat that does not feel normal, very bad dizziness or passing out, fast heartbeat, more thirst, seizures, feeling very tired or weak, not hungry, unable to pass urine or change in the amount of urine produced, dry mouth, dry eyes, or very bad upset stomach or throwing up.
Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
Signs of high blood sugar like confusion, feeling sleepy, more thirst, more hungry, passing urine more often, flushing, fast breathing, or breath that smells like fruit.
Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
Signs of a pancreas problem (pancreatitis) like very bad stomach pain, very bad back pain, or very bad upset stomach or throwing up.
Very bad dizziness or passing out.
A burning, numbness, or tingling feeling that is not normal.
Chest pain or pressure.
Not able to get or keep an erection.
Fever, chills, or sore throat; any unexplained bruising or bleeding; or feeling very tired or weak.
Restlessness.
Low mood (depression).
Swelling, warmth, numbness, change of color, or pain in a leg or arm.
Change in eyesight.

What are some other side effects of metolazone?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

Constipation, diarrhea, stomach pain, upset stomach, throwing up, or feeling less hungry.
Feeling dizzy, sleepy, tired, or weak.
Headache.
Joint pain.
Bloating.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out metolazone?

Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.