Brand Name(s):

  • Mykrox®¶
  • Zaroxolyn®

WHY is this medicine prescribed?

Metolazone, is used to reduce the swelling and fluid retention caused by heart failure or kidney disease. It also is used alone or with other medications to treat high blood pressure. Metolazone is in a class of medications called diuretics ('water pills'). It causes the kidneys to reduce the amount of water and salt in the body by increasing the amount of urine.

HOW should this medicine be used?

Metolazone comes as a tablet to take by mouth. It is usually taken once a day. Take metolazone at 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 metolazone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of metolazone and gradually increase your dose, depending on your response to this medication.

Metolazone controls high blood pressure but does not cure it. Continue to take metolazone even if you feel well. Do not stop taking metolazone without talking to your doctor.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking metolazone,

  • tell your doctor and pharmacist if you are allergic to metolazone, sulfa drugs, thiazides, any other medications, or any of the ingredients in metolazone tablets. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin (Coumadin); aspirin and other nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); corticotropin; digoxin (Lanoxin); furosemide (Lasix); insulin or other medications for diabetes; lithium (Eskalith, Lithobid); medications for asthma and colds; medications for pain or seizures; methenamine (Hiprex, Urex); other medications for high blood pressure; sedatives; oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); tranquilizers; and vitamin D. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have kidney or liver failure. Your doctor will probably tell you not to take metolazone.
  • tell your doctor if you have or have ever had diabetes, gout, systemic lupus erythematosus (SLE, a chronic inflammatory condition), or parathyroid, heart, kidney, or liver disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking metolazone, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking metolazone.
  • you should know that metolazone may make you dizzy or drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
  • ask your doctor about the safe use of alcoholic beverages while you are taking metolazone. Alcohol can make the side effects from metolazone worse.
  • plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Metolazone may make your skin sensitive to sunlight.
  • you should know that metolazone 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 metolazone. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.

What SPECIAL DIETARY instructions should I follow?

Follow your doctor's directions. they may include a daily exercise program and a low-sodium or low-salt diet, potassium supplements, and increased amounts of potassium-rich foods (e.g., bananas, prunes, raisins, and orange juice) in your diet.

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 the 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?

Metolazone may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • dizziness
  • weakness
  • restlessness
  • headache
  • muscle cramps
  • joint pain or swelling
  • constipation
  • diarrhea

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

  • dry mouth, dark urine, decreased sweating, dry skin, and other signs of dehydration
  • chest pain
  • rapid, irregular, or pounding heartbeats
  • hives
  • rash
  • itching
  • blistering or peeling skin
  • swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
  • hoarseness
  • difficulty swallowing or breathing
  • sore throat with fever
  • unusual bleeding or bruising
  • upset stomach
  • extreme tiredness
  • loss of appetite
  • pain in the upper right part of the stomach
  • yellowing of the skin or eyes
  • flu-like symptoms

Metolazone may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

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 [at Web Site] or by phone [1-800-332-1088].

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

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include the following:

  • dizziness
  • drowsiness
  • fainting
  • slow or difficult breathing
  • upset stomach
  • coma

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to metolazone.

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

Learn the brand name of your medication. Do not switch brands without talking to your doctor or pharmacist, as different brands of metolazone may work differently in the body.

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

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: August 15, 2013.