Metolazone - oral

Patient Medicine Information
Why do I need this medicine?
Metolazone is used to treat water retention caused by heart failure or kidney disease. Water retention may be noticed as swelling of the feet, ankles, lower leg and hands, or shortness of breath. For this reason, it is commonly known as a "water pill".

This medicine is also used on its own or together with other medicines to keep your blood pressure under control.
How do I take this medicine?
Take Metolazone exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

You may take this medicine with or without food. Try to take it at the same time each day.

You may need to pass urine more often while being treated with Metalozone. Take it early in the day, preferably in the morning, to avoid waking up frequently at night to go to the toilet.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the course of your treatment depending on your condition and response to the medication.

Metalozone must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
When should I not use this medicine?
Alert your doctor if you have the following conditions:
  • unable to pass urine
  • hepatic coma or precoma (brain impairment associated with liver disease)
as Metalozone may not be suitable for you.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • diabetes
  • gout (high uric acid level in the blood)
  • Addison’s disease (a rare disorder where the adrenal glands produce insufficient hormones)
  • systemic lupus erythematosus or SLE (autoimmune disease that causes inflammation)
  • hypokalaemia (low potassium level in the blood)
  • allergic reaction to sulfonamide-containing medicines
  • kidney disease
  • liver disease
Let your doctor know if you are pregnant or breastfeeding.

Be sure to check with your doctor or pharmacist before giving Metolazone to the elderly. Elderly people may be more sensitive to the side effects.

Do not switch between different brands unless advised by your doctor.

If you are going to have certain laboratory tests or an operation, including minor surgery and dental work, inform your doctor or dentist that you are taking this medicine.

Why is it important to keep my appointments with the doctor?

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
  • Your blood pressure may fall to unsafe levels without you noticing it. Monitor your blood pressure regularly during treatment.
  • Routine tests (e.g. kidney function, uric acid, and electrolyte levels) may be done while you are being treated with this medicine. Your doctor will advise you about how often you need to have these tests.
  • Regular monitoring for signs of electrolyte imbalance or allergic reactions may also be needed.
What lifestyle changes can I make to improve my blood pressure?

Regular exercise and eating a healthy diet will help control your blood pressure and improve your overall health. Engage in physical activity like walking for at least 30 to 60 minutes on most days of the week. If you have not exercised for a long time, start with light exercises such as slow walks. Speak to your doctor about what type of exercise would be suitable for you. Follow a healthy diet plan by eating more fruits, vegetables, whole grains and low-fat dairy products and reduce your intake of foods high in saturated fat, cholesterol and sodium. Cutting down on deep-fried foods and using less salt when cooking can kick-start your healthy diet.

If you smoke, you should try to quit. Smoking is harmful to your blood pressure, heart and overall health. Speak to your doctor or pharmacist about ways to stop your smoking habit.
What side effects could I experience?
Metolazone may cause any of the following side effects: headache, dizziness, drowsiness, blurred vision, nausea, diarrhoea, vomiting, chills, and joint pain.

This medicine may cause your blood pressure to fall suddenly when you get up from a sitting or lying down position and you may feel giddy. To minimise this problem, stand up slowly.

You may need to pass urine more often while you are being treated with Metolazone. As your body adjusts to the medicine, this urination effect should also decrease.

Metolazone may also make your skin more sensitive to sunlight. Apply sunscreen when going outdoors and avoid prolonged exposure to sunlight and UV lamps.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
  • signs of allergic reactions e.g. rashes, breathlessness, swelling of the face, eyes, mouth or throat
  • signs of electrolyte imbalance e.g. muscle pain or cramps, weakness, fast or irregular heartbeat, dry mouth, increased thirst, restlessness, passing out
  • unable to pass urine or pass urine less frequently than usual
  • frequent and persistent sore throat with fever; unusual bleeding or bruising
  • rashes with peeling of the skin or blistering of the lips, mouth or eyes accompanied by fever
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Inform your doctor and pharmacist if you are taking any of these medicines:
  • other medicines for water retention or “water pills” e.g. furosemide, hydrochlorothiazide
  • medicines for high blood pressure e.g. captopril, amlodipine
  • NSAIDs (medicines for pain and inflammation) e.g. aspirin, indometacin, ketoprofen
  • lithium (medicine for mood disorder)
  • methenamine (certain antibiotic)
  • digoxin (medicine for heart disease)
This list does not include all medicines that may interact with Metolazone.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol.

Cut down on your salt intake. This may help lower your blood pressure and improve your overall health. Discuss with your doctor or dietitian about ways to cut down on your salt intake.
How should I store this medicine?
Store in a cool, dry place away from the reach of children. Protect from light.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on metolazone - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2023 MIMS. All rights reserved. Powered by
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