Methadone for pain

Methadone is used for pain relief. Find out how to take it safely and possible side effects.

Type of medicine Also called
  • Belongs to a group of medicines known as analgesics (pain relief medicines)
  • Opioid pain reliever
  • Biodone
  • Methatabs

What is methadone?

Methadone is used for the relief of moderate to severe pain like pain caused by a terminal illness such as cancer. Methadone belongs to a group of medicines called opioids. They act on your brain and nervous system to reduce pain. Methadone is usually used when other opioids such as such as morphine or oxycodone don’t work well enough. Read more about painpain-relief medication and opioid painkillers.


  • In New Zealand, methadone is available as an injection, tablets and in oral liquid form.
  • The dose of methadone is different for different people. 
  • Depending on your pain, your doctor may advise that you take regular doses or take methadone only when you need it for pain relief. Make sure you know which is right for you.
  • Always take your methadone exactly as your doctor has told you. Do not change the dose yourself.
  • The pharmacy label on your medicine will tell you how much methadone to take, how often to take it and any special instructions.

My dose

Morning Lunch Dinner Bedtime

How to take methadone

  • You can take methadone with or without food.
  • Tablets: Take the tablets with a glass of water. If you need to halve methadone tablets to get the correct dose, ask your healthcare provider or pharmacist how to do it accurately.
  • Liquid: Measure the liquid carefully with an oral syringe or measuring spoon. You can get these from your pharmacy. Do not use a kitchen spoon as it will not give you the right amount. Methadone liquid comes in different strengths. Always read the label carefully. The pharmacy label on your medicine will tell you how much methadone to take, how often to take it and any special instructions.
  • Limit or avoid alcohol while you are taking methadone. Taking methadone with alcohol can make you more sleepy, drowsy or dizzy.
  • Missed dose: If you forget to take your dose, take it as soon as you remember that day. But if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the amount.
  • Do not change the dose yourself. If you take too much of methadone you could be at risk of overdose. Too much methadone may make you sleepy and can slow your breathing. Contact your doctor if you have taken more than your prescribed dose.
  • The pain relief may not be immediate. It can take a day or more after starting methadone before you notice any improvement in pain. It can take a week or longer to get its full effect. Until then your pain may not be fully controlled. Do not take extra doses of pain relief medicines or change the dose unless you have talked to your doctor.
  • Never share your medicine. Methadone is prescribed specifically to you and may cause harm to others.

Common concerns about methadone

  • Because methadone is known to be used for substance misuse, people prescribed this medicine often have concerns about negative associations.
  • The way methadone is used in substance misuse is different from the way methadone is prescribed for pain management.
  • Discuss any concerns you have about this with your healthcare provider or pharmacist.
  • If you take methadone for a long time, you can become physically and mentally dependent on methadone.
  • If you are worried about becoming dependent on methadone, talk to your doctor.

 Precautions before starting methadone

  • Do you have liver or kidney problems?
  • Do you have breathing problems such as asthma, COPD or sleep apnoea?
  • Do you have epilepsy?
  • Have you had an accident or a head injury?
  • Do you have problems with your bowel such as constipation?
  • Are you pregnant or breastfeeding?
  • Are you taking any other medicines? This includes any medicines you buy without a prescription, such as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start methadone. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

What are the side effects of methadone for pain?

Like all medicines, methadone can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sleepy, dizzy or tired
  • Reduced concentration
  • This is common when starting methadone or after increasing the dose.
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Do not drink alcohol.
  • Feeling sick (nausea) or vomiting
  • This common when you first start taking methadone.
  • Mostly this settles and goes away.
  • Tell your doctor if this is troublesome.
  • You may need an anti-sickness tablet at times.
  • Constipation
  • Ask your doctor to prescribe a suitable laxative, which you need to take on a regular basis.
  • You also need to eat more fruit, vegetables, brown bread and bran-based breakfast cereals and drink plenty of water. 
  • Read more about how to ease and prevent constipation.
  • Headache, dry mouth, altered vision
  • These are quite common when you first start taking methadone and usually go away with time.
  • Tell your doctor if troublesome.
  • Changes in heart rate (fast or irregular heart beat)
  • Your doctor may do a heart test (ECG) before you start and while you are taking methadone.
  • Tell your doctor immediately or phone Healthline 0800 611 116.
  • Frequent mood changes, anxiety, depression, thoughts of suicide or abnormal behaviours
  • Tell your doctor immediately or phone Healthline 0800 611 116.
  • Signs of an allergic reaction, such as skin rashes, itches, swelling of your face, lips or mouth, or difficulty breathing  
  • Tell your doctor immediately or phone Healthline 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product


Methadone may interact with other medicines, including herbal supplements, so check with your doctor or pharmacist before starting methadone and before starting any new medicines.

Methadone may interact with medicines available without a prescription such as cough suppressants (eg, Benadryl Dry Forte®, Duro-Tuss®) and sedating antihistamines (eg, Phenergan®) ®) or pain relief (eg, Nurofen Plus). Avoid grapefruit while on methadone as it can affect how your methadone works.

Learn more

Methadone NZ Formulary Patient Information 


  1. Methadone hydrochloride NZ Formulary
  2. Strong opioids for pain management in adults in palliative care BPAC, NZ, 2012
Credits: Sandra Ponen, Pharmacist. Reviewed By: Maya Patel, Pharmacist, Auckland Last reviewed: 13 Sep 2021