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Drugs reference index «Zaroxolyn»


Generic name: MetolazoneBrand names: Mykrox, Zaroxolyn

Why is Zaroxolyn prescribed?

Zaroxolyn is a diuretic used in the treatment of high blood pressure and other conditions that require the elimination of excess fluid from the body. These conditions include congestive heart failure and kidney disease. When used for high blood pressure, Zaroxolyn can be used alone or with other high blood pressure medications. Diuretics prompt your body to produce and eliminate more urine, which helps lower blood pressure.

Zaroxolyn is also occasionally prescribed for kidney stones.

Most important fact about Zaroxolyn

If you have high blood pressure, you must take Zaroxolyn regularly for it to be effective. Since blood pressure declines gradually, it may be several weeks before you get the full benefit of Zaroxolyn; and you must continue taking it even if you are feeling well. Zaroxolyn does not cure high blood pressure; it merely keeps it under control.

How should you take Zaroxolyn?

Take Zaroxolyn exactly as prescribed. Stopping Zaroxolyn suddenly could cause your condition to worsen.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for the next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at the same time.
  • Storage instructions...Store at room temperature in a tightly closed, light-resistant container.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Zaroxolyn.

  • Side effects may include:Artery damage, blood abnormalities, chest pain/discomfort, fainting, inflammation of the pancreas, joint pain, weakness, yellow eyes and skin

Why should Zaroxolyn not be prescribed?

If you are unable to urinate or have severe liver disease, you should not take Zaroxolyn.

If you are sensitive to or have ever had an allergic reaction to Zaroxolyn or other diuretics, you should not take Zaroxolyn.

Special warnings about Zaroxolyn

Diuretics can cause your body to lose too much potassium. Signs of an excessively low potassium level include muscle weakness and rapid or irregular heartbeat. To boost your potassium level, your doctor may recommend eating potassium-rich foods or taking a potassium supplement.

If you are taking Zaroxolyn, your doctor will do a complete assessment of your kidney function and continue to monitor it.

Do not interchange Zaroxolyn and other formulations of metolazone. The brands vary in potency of action.

If you have liver disease, diabetes, gout, or lupus erythematosus (a disease of the immune system), Zaroxolyn should be used with caution.

If you have had an allergic reaction to sulfa drugs, thiazides, or quinethazone, you may be at greater risk for an allergic reaction to Zaroxolyn. You can have an allergic reaction to Zaroxolyn even if you have never had allergies or asthma.

Dehydration, excessive sweating, severe diarrhea, or vomiting could deplete your fluids and cause your blood pressure to become too low. Be careful when exercising and in hot weather.

Notify your doctor or dentist that you are taking Zaroxolyn if you have a medical emergency and before you have surgery or dental treatment.

Possible food and drug interactions when taking Zaroxolyn

Zaroxolyn may intensify the effects of alcohol. Avoid drinking alcohol while taking Zaroxolyn.

If Zaroxolyn is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Zaroxolyn with the following:

ACTHAntidiabetic drugsBarbiturates such as phenobarbitalCorticosteroids such as prednisoneDigitalis glycosidesInsulinLithiumLoop diuretics such as furosemideMethenamineNarcoticsNonsteroidal anti-inflammatory agentsNorepinephrineOther high blood pressure medicationsTubocurarine

Special information if you are pregnant or breastfeeding

The effects of Zaroxolyn during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. Zaroxolyn appears in breast milk and could affect a nursing infant. If Zaroxolyn is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment is finished.

Recommended dosage for Zaroxolyn


Your doctor will adjust the dosage of Zaroxolyn to your individual needs and will use the lowest possible dose with the maximum effect. The time it takes for Zaroxolyn to become effective varies from person to person, depending on the diagnosis.

Most starting doses of Zaroxolyn will be given once a day.

Edema Due to Heart or Kidney Disorders

The usual dosage is 5 milligrams to 20 milligrams once a day.

Mild to Moderate High Blood Pressure

The usual dosage is 2.5 milligrams to 5 milligrams once a day.


The safety and effectiveness of Zaroxolyn in children have not been established.


Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.

  • Symptoms of Zaroxolyn overdose may include:Difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, lethargy leading to coma
  • Zaroxolyn MedFacts Consumer Leaflet (Wolters Kluwer)
  • Zaroxolyn Concise Consumer Information (Cerner Multum)
  • Zaroxolyn Advanced Consumer (Micromedex) - Includes Dosage Information
  • Zaroxolyn Prescribing Information (FDA)
  • Metolazone Professional Patient Advice (Wolters Kluwer)
  • Metolazone Prescribing Information (FDA)
  • Mykrox Prescribing Information (FDA)

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