Methadone - oral

Patient Medicine Information
Why do I need this medicine?
Methadone is an opioid analgesic (strong painkiller). It is used to treat severe pain.

This medicine may also be used to treat addiction to opioid drugs (strong painkiller).

Methadone is meant to be used as part of a total drug addiction care programme that includes counselling and social support.
How do I take this medicine?
Take Methadone 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.

This medicine is available as a tablet, dispersible tablet, oral solution or oral concentrate.

If you are taking the dispersible tablet, do not chew or swallow it, dissolve the tablet in a glass of water, orange juice or any acidic fruit drink.

If you are taking an oral solution, shake the bottle well before you take it to ensure that the liquid is evenly mixed. Use the measuring spoon or cup provided to measure your dose.

If you are taking the oral concentrate, dilute it with another liquid before taking it.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on your condition.

Do not stop taking this medicine unless instructed otherwise, as stopping it suddenly could worsen your condition.
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:
  • respiratory depression (slow or ineffective breathing)
  • asthma
  • blocked bowels
  • paralytic ileus (bowel obstruction caused by slow movement or paralysis of the intestines)
  • ulcerative colitis (inflammation of the large intestines)
  • head injury
  • severe liver disease
  • consume large amounts of alcohol or if you are a frequent drinker
as Methadone may not be suitable for you.

Do not take Methadone if you are currently taking or have taken a medicine that is used to treat depression known as a monoamine oxidase inhibitor (MAOI) such as isocarboxazid, phenelzine and tranylcypromine in the last 14 days.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • heart disease
  • long-term lung disease that causes airflow obstruction making it hard to breathe
  • Addison’s disease (low level of cortisol in your blood)
  • fits or seizures
  • severe tremors, hallucination and disorientation caused by withdrawal from alcohol
  • mental health disorders (e.g. depression, anxiety)
  • prostate enlargement
  • thyroid disease
  • low potassium level in the blood
  • low magnesium level in the blood
  • 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 this medicine to the elderly, debilitated (a person who is physically or mentally weak usually due to illness or old age) or obese patients. They may be more sensitive to the side effects.

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.
  • Routine tests (e.g. lung function, ECG monitoring) 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.
  • Your blood pressure may rise or fall to unsafe levels without you noticing it. Monitor your blood pressure during treatment.
What side effects could I experience?
Methadone may cause drowsiness. If affected, do not drive or take part in any activity in which you need to be alert.

Other side effects include any of the following: blurred vision, dizziness with sensations of spinning, nausea, vomiting, dry mouth, light-headedness, rash.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any breathing problems.

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?
Do not take Methadone if you are currently taking or have taken a medicine to treat depression known as a monoamine oxidase inhibitor (MAOI) such as isocarboxacid, phenelzine and tranylcypromine in the last 14 days.

Inform your doctor and pharmacist if you are taking any of these medicines:
  • medicines for depression e.g. fluvoxamine, fluoxetine
  • medicines for HIV infection e.g. efavirenz
  • certain antibiotics e.g. rifampicin, clarithromycin, erythromycin
  • medicines for fungal infection e.g. fluconazole, ketoconazole
  • medicines for epilepsy (fits or seizures) e.g. phenytoin, carbamazepine
This list does not include all medicines that may interact with Methadone.

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, grapefruit and St John’s wort.
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 methadone - 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 © 2021 MIMS. All rights reserved. Powered by
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