> Western Medicines > Methadone


Used for: Severe ongoing pain, Opioid dependence
Chinese name:

What is Methadone for?

Methadone belongs to a class of medications called opioid analgesics. It works by inhibiting nerve signal transmission of pain in the brain and nervous system. It is a powerful analgesic and is used for severe pain management, for example in chronic pain management for cancer patients. Methadone is also used to treat people with opioid addiction by producing similar effects and preventing withdrawal symptoms in people who stopped using opioid drugs.

How to use it?

Methadone is available as oral tablets and linctus. You can take Methadone with or without food. Taking it with food may help to reduce gastrointestinal discomfort.


For severe ongoing pain
Initially 2.5-10 mg every 8-12 hours. Dose may be increased if necessary according to severity of pain.


For opioid dependence
Linctus: Initially 10-30 mg daily. Dose is increased every few days as necessary up to the usual dose of 60-120 mg daily according to signs of withdrawal. Maximum weekly dose increase is 30 mg.


Neonate 0-4 month
Initially 100 mcg per kg body weight. Dose is increased in steps of 50 mcg per kg body weight every 6 hours until opioid withdrawal symptoms are controlled.

What are the side effects of Methadone?

Common side effects of Methadone include constipation, dizziness and drowsiness, dry mouth, euphoric mood, flushing, hallucinations, nausea and vomiting (more common on initiation), respiration depression (with high dose). Like all opioid medications, people can become tolerant or addicted to Methadone, which can result in withdrawal symptoms when you try to stop the medicine.

Who should not take Methadone?

  • People allergic to Methadone or any component of the formulation.
  • Patients with respiratory depression, serious bronchial asthma or gastrointestinal obstruction.
  • People who are taking or took monoamine oxidase inhibitors (MAOIs) within the past 14 days.

Pharmacist Tips:

  • Note that opioids have the potential to be addictive and you can become tolerant over time.
  • Tell your doctor if you experience severe side effects, such as difficulty breathing.
  • Do not stop the medication abruptly if you have used Methadone over long periods of time.
  • Eat more high-fibre foods, drink more water and do more exercise to reduce the side effects of constipation.
  • It is best to avoid alcohol while taking Methadone.

Common dosing schedule:
Oral Methadone can be taken with or after a meal to minimize gastrointestinal discomfort.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Methadone may interact with:

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Methadone in Hong Kong?

In Hong Kong, Methadone is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Methadone in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Available dosage
  • 80mg/20mL (Linctus)
  • 5mg (Tablets)
Drug class
Drugs In Substance Dependence, Analgesics
Sub class
Opioid Analgesics
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