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

metolazone, Oral tablet

All Brands

  • Zaroxolyn (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 metolazone

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1

Metolazone is used to treat high blood pressure (hypertension) and the buildup of excess fluid and salt in your body (edema).

2

This drug is available as a 2.5-mg, 5-mg, or 10-mg tablet. It’s taken by mouth once per day.

3

The starting dose for adults with high blood pressure is usually 2.5–5 mg of metolazone by mouth once per day.

4

The most common side effects of metolazone are constipation, dry mouth, diarrhea, headache, stomach pain, and blurred vision.

5

Metolazone can cause low blood pressure when you stand up (orthostatic hypotension).

IMPORTANT INFORMATION

Low sodium and potassium levels

In rare cases, taking metolazone has suddenly led to low sodium levels (hyponatremia) or low potassium levels (hypokalemia) or both. If this occurs, your doctor may have you stop using metolazone.

High nitrogen levels

Metolazone can cause high levels of nitrogen in your body (azotemia). If you have kidney disease, and experience high levels of nitrogen in your body or you’re having trouble urinating (or are not urinating as often), then your doctor will stop treatment with metolazone.

Low blood pressure when standing

Metolazone can cause low blood pressure when you stand up (orthostatic hypotension).

Drug features

Metolazone is a prescription drug. It’s available as a tablet you take by mouth. It’s also available as a generic drug. Generic drugs usually cost less. In some cases they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you. Metolazone may be taken as part of a combination therapy with other medications.

Why it's used

Metolazone is used to treat high blood pressure. It’s also used to treat the buildup of excess fluid and salt in your body.

How it works

Metolazone belongs to a class of drugs called diuretics.

More Details

How it works

Metolazone belongs to a class of drugs called diuretics. A class of drugs is a group of medications that work in a similar way. They’re often used to treat similar conditions. Diuretics work by causing you to urinate more. This helps remove excess fluid and salt from your body. Removing this excess fluid and salt also helps to lower your blood pressure.

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metolazone Side Effects

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More Common Side Effects

The most common side effects that occur with metolazone include:

  • abdominal pain

  • blurred vision

  • constipation

  • diarrhea

  • dry mouth

  • headache

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.

  • Allergic reactions. Symptoms can include:

    • rash
    • hives
    • itching
    • raised welts
    • facial swelling
    • fever
    • difficulty breathing
    • peeling or blistering skin
  • Heart problems. Symptoms can include:

    • irregular heartbeat
    • chest pain
  • Liver problems. Symptoms can include:

    • yellowing of the whites of your eyes or your skin
    • weakness or tiredness
    • abdominal pain
    • nausea
    • vomiting
  • Nerve problems. Symptoms can include:

    • muscle pain or cramps
    • numbness in your hands or feet
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug isn’t sedating.

Mild side effects 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.

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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metolazone May Interact with Other Medications

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Metolazone 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

Drinking alcohol while you take this drug can increase your risk for low blood pressure when you stand up (orthostatic hypotension).

Medications that might interact with this drug

Antibiotics

Taking certain antibiotics with metolazone can make metolazone not work as well. These include:

  • methenamine

Other blood pressure drugs

These drugs can lower your blood pressure too much if taken with metolazone. They include:

  • angiotensin-converting enzyme (ACE) inhibitors, such as:
    • benazepril
    • captopril
    • cilazapril
    • enalapril
    • enalaprilat
    • fosinopril
    • imidapril
    • moexipril
    • perindopril
    • quinapril
    • ramipril
    • trandolapril
  • angiotensin II receptor blockers (ARBs), such as:
    • irbesartan
    • losartan
    • olmesartan
    • telmisartan
    • valsartan
  • beta-blockers, such as:
    • acebutolol
    • arotinolol
    • atenolol
    • betaxolol
    • bisoprolol
    • esmolol
    • metoprolol
    • nadolol
    • nebivolol
    • penbutolol
    • pindolol
    • propranolol
    • timolol (systemic)
  • calcium channel blockers, such as:
    • amlodipine
    • felodipine
    • nicardipine
    • nifedipine
  • direct renin Inhibitors, such as:
    • aliskiren
  • loop diuretics, such as:
    • bumetanide
    • furosemide
    • indapamide
    • torsemide
  • potassium-sparing diuretics, such as:
    • eplerenone
    • spironolactone
    • triamterene

Blood thinners (anticoagulants)

Your dose of these drugs may need to be increased if you’re taking them with metolazone. When you take them with metolazone, they may not work as well. These drugs include:

  • warfarin

Corticosteroids

Taking these medications with metolazone may increase your risk for hypokalemia (low sodium). These include:

  • prednisone
  • prednisolone
  • methylprednisolone

Diabetes drugs

Your dose of these drugs may need to be increased if you’re taking them with metolazone. When you take them with metolazone, they may not work as well. These drugs include:

  • insulin

Diuretics

Taking these drugs with metolazone may increase your risk for low sodium levels (hypokalemia). These include:

  • furosemide

Heart drugs

Metolazone may increase the effects of these drugs. These drugs include:

  • digoxin

Mood stabilizers

Metolazone may increase the effects of these drugs. These drugs include:

  • lithium

Pain drugs

Taking the following pain drugs with metolazone can make metolazone not work as well:

  • aspirin
  • nonsteroidal anti-inflammatory drugs (NSAIDs), such as:
    • diclofenac
    • ibuprofen
    • indomethacin
    • ketoprofen
    • ketorolac
    • meloxicam
    • nabumetone
    • naproxen
    • piroxicam
  • COX-2 Inhibitors
    • celecoxib

Taking the following pain drugs with metolazone can lower your blood pressure too much:

  • barbiturates, such as:
    • amobarbital
    • butabarbital
    • butalbital
    • methohextal
    • pentobarbital
    • phenobarbital
    • secobarbital
    • thiopental
  • narcotics, such as:
    • codeine
    • dihydrocodeine
    • fentanyl
    • hydrocodone
    • hydromorphone
    • levorphanol
    • mepiridine
    • methadone
    • morphine
    • opium
    • oxycodone
    • oxymorphone
    • tramadol

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.
Metolazone warnings
anuria
People with anuria

If your body isn’t able to make urine (anuria), you shouldn’t take metolazone. Metolazone is removed from your body by your kidneys. If your kidneys aren’t working well, this will make it harder for your body to get rid of the drug.

liver failure
People with liver failure

You shouldn’t take metolazone if you have advanced stages of liver failure.  Metolazone can cause changes to your electrolyte levels, which may bring on a hepatic coma in people with liver disease.

diabetes
People with diabetes

Metolazone can increase your blood sugar level. Talk to your doctor before using this drug if you have diabetes.

gout
People with gout

Metolazone can increase the amount of acid in your body. This can cause gouty attacks.

kidney disease
People with kidney disease

Metolazone is eliminated from your body through your kidneys and can build up in your body if your kidneys aren’t working as well as they should. This can lead to toxicity. Tell your doctor if you have kidney disease or kidney damage.

systemic lupus erythematosus
People with systemic lupus erythematosus

Taking metolazone may make your systemic lupus erythematosus worse.

pregnant women
Pregnant women

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

  1. Studies of the drug in pregnant animals haven’t 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.

Speak with your doctor if you’re pregnant or planning to become pregnant. Metolazone should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus.

breastfeeding
Women who are breast-feeding

Metolazone may pass into breast milk and can cause serious adverse effects. Talk to your doctor before taking metolazone if you’re breast-feeding or plan to breast-feed.

for children
For children

This medicine shouldn’t be used in people younger than 18 years.

call doctor
When to call the doctor

Call your doctor or go to the emergency room if you have chest pain, a headache, jaw pain, upper back pain, nausea or vomiting, or trouble breathing. These may be symptoms of a heart attack.

allergies
Allergies

Metolazone can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

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

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How to Take metolazone (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?

Hypertension

Brand: Zaroxolyn

Form: Oral tablet
Strengths: 2.5 mg, 5 mg, 10 mg

Generic: metolazone

Form: Oral tablet
Strengths: 2.5 mg, 5 mg, 10 mg
Adult dosage (ages 18 years and older)

The usual dose for mild to moderate hypertension is 2.5–5 mg by mouth, once per day.

Child dosage (ages 0–17 years)

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

Special considerations

People with kidney disease: If you have kidney disease, you may need a lower dose or you may need a different dosing schedule. Metolazone is removed from your body by your kidneys. It can build up in your body if your kidneys aren’t working as well as they should. This can lead to toxicity.

People with heart disease: If you have heart disease or decreased heart function you may need a lower dose or you may need a different dosing schedule.

Edema

Brand: Zaroxolyn

Form: Oral tablet
Strengths: 2.5 mg, 5 mg, 10 mg

Generic: metolazone

Form: Oral tablet
Strengths: 2.5 mg, 5 mg, 10 mg
Adult dosage (ages 18 years and older)

The usual dose for edema is 5–20 mg by mouth, once per day.

Child dosage (ages 0–17 years)

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

Special considerations

People with kidney disease: If you have kidney disease, you may need a lower dose or you may need a different dosing schedule. Metolazone is removed from your body by your kidneys. It can build up in your body if your kidneys aren’t working as well as they should. This can lead to toxicity.

People with heart disease: If you have heart disease or decreased heart function you may need a lower dose or you may need a different dosing 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
Healthline Pharmacist Editorial Team

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

If you don't take it at all

If you don’t take metolazone at all, your blood pressure or edema, or both, might not be controlled. This may lead to a heart attack, stroke, pain, or infection.

If you stop taking it suddenly

If you’re taking metolazone for high blood pressure and suddenly stop taking it, you may experience rebound high blood pressure. This is a sudden increase in your blood pressure after you stop taking your blood pressure medication. Symptoms of rebound hypertension include headache, confusion, chest pain, sweating, nausea, and vomiting.

If you don't take it on schedule

If you don’t take metolazone according to the schedule for your doses, it may not work as well. In order for this drug to work, you need a consistent amount of it in your body at all times.

If you take too much

Taking too much metolazone can cause dizziness, drowsiness, fainting spells, low blood pressure when you stand up, changes in your electrolytes, and trouble breathing. If you think you have taken too much metolazone, you should go to the nearest emergency room or contact poison control right away.

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember, unless you remember just a few hours before the time for your next dose. Then only take one dose. Never try to catch up by taking two doses at once. This could result in toxic side effects.

How to tell if the drug is working

You may or may not be able to tell if metolazone is working; however, your doctor will check your blood pressure and fluid volume regularly to see if they’re at normal levels and controlled. You also may purchase a blood pressure monitor from your local pharmacy so that you can check your blood pressure yourself.

Depending on what is being treated, metolazone is used for short-term or long-term therapy.

For swelling and water retention in your legs and arms, metolazone is used as short-term therapy. For high blood pressure, it’s used as long-term therapy.

Important considerations for taking metolazone

Metolazone should be taken early in the day

This helps to avoid frequent urination throughout the night.

Store metolazone at room temperature

  • Keep it between 68°F (20ºC) and 77°F (25°C).
  • Don’t freeze metolazone.
  • Keep it away from light and high temperature.
  • Keep your drugs away from areas where they could get wet, such as bathrooms. Store these drugs away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as 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 staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

You may need to buy a blood pressure monitor. These can be purchased at most pharmacies.

Clinical monitoring

While you’re taking metolazone, your doctor will regularly monitor your electrolyte levels, blood sugar level, blood acid levels, calcium levels, heart function, liver function, and kidney function.

Sun sensitivity

Metolazone can make your skin more sensitive to the sun. This increases your risk of sunburn. Avoid the sun if you can. If you can’t, be sure to wear protective clothing and apply sunscreen.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

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

What does the pill look like?

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How Much Does metolazone Cost?

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Lowest price for metolazone

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

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These prices represent the lowest priced national pharmacies for metolazone 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 29, 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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