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What does it do?

Methadone is used to relieve strong pain and sometimes for other conditions.

How should you take it?

Take methadone regularly as directed. You can take it with or without food.
Tablet: Take with a glass of water.
Liquid: Measure carefully with an oral syringe or measuring spoon.

What if you forget a dose?

If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Some medicines available without a prescription may react with methadone including:

  • sedating antihistamines (e.g. Phenergan®)
  • cough suppressants (e.g. Duro-Tuss®, Benadryl Dry Forte®)
  • Ural® sachets or Sodibic® capsules
  • some migraine medicines, such as sumatriptan (e.g. Sumagran Active®)

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. St John's wort) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Slow or shallow breathing, hard to wake up

Seizures

Fainting

Tell your doctor immediately

Confusion, hallucinations, mood changes

Tummy pain (new or getting worse)

Tell your doctor

Constipation

Take your prescribed laxatives. Tell your doctor

Drowsiness, dizziness

Nausea, vomiting, dry mouth or throat

Itching, flushing, sweating

Strange or uncontrolled movements

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you have bowel or kidney problems, sleep apnoea, if you have ever had a seizure, or have had a recent head injury.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Your doctor may do a heart test (ECG) before you start and while you are taking methadone.
  • If methadone is not relieving your pain contact your health professional – your dose may need changing.
  • Methadone can impair your ability to do tasks such as driving or using machines. Alcohol makes this worse. Discuss your risk with your health professional. (search NZTA - Are you safe to drive?)
  • Methadone may be addictive with long-term use.
  • Long-term use of methadone may cause side effects such as less interest or trouble having sex, changes in periods, or weak bones. It may also make some types of pain worse. Discuss with your doctor.
  • If you have been taking methadone regularly for a long time, talk to your doctor before stopping.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. September 2022

For more general information about this sheet annd its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed