Skip Ribbon Commands
Skip to main content


Drug Class: Commonly Known As: Category:
Analgesic Adult

Methadone - What is it for

Methadone is used together with medical supervision and counseling to treat opioid dependence patients. It also prevents withdrawal symptoms in these patients.

Methadone - Side Effects, Precautions, and Contraindications

What side effects can Methadone cause?

Most of these side effects will get better or go away as the body gets used to the medication.

Common side effects include:

  • Dizziness or light-headedness (Rise slowly over several minutes from sitting or lying position).
  • Drowsiness. Do not drive or operate heavy machinery if affected
  • Constipation
  • Nausea or vomiting

Inform your doctor if the side effects above become severe and bothersome.


Rare but serious effects may sometimes occur. Contact the doctor as soon as possible if any of the following are noticed:

  • Allergic reactions: Skin rash, itching, difficulty in breathing, swelling of face, lips, tongue or throat
  • Shallow breathing
  • Severe dizziness or passing out
  • Fast heartbeat
  • Mental alteration
  • Feeling extremely tired or weak
  • Seizures (fits)

Before taking Methadone , what precautions must I follow?

What food or medicine must I avoid when I take Methadone ?

Avoid alcoholic drink.

Avoid taking grapefruit or grapefruit juice while taking this medicine.

Methadone - Dosage and How to Use

How should Methadone be used?

Follow the directions on the medicine label and administer the medicine exactly as directed. Do not administer more or less than what is prescribed by your doctor. The dose for each patient is individually determined by the doctor.

What should I do if I miss a dose?

Take the missed dose as soon as you remember. However, if you omissed the dose for more than half the time interval (e.g. more than 4 hours for an 8-hourly dosing), skip the missed dose and administer the medicine at the usual time. Inform your doctor if you missed 3 days or more of the regular prescribed dose. DO NOT take two doses at the same time to make up for a missed one.

What should I do if I overdose?

In cases you or someone else may have taken an overdose of Methadone tablets, get an emergency help and call 995 immediately.

Signs and symptoms of overdose include cold clammy (pale) skin, confusion, seizures, severe dizziness (low blood pressure), severe drowsiness, severe nervousness or restlessness, slow or troubled breathing and severe weakness. Overdose can result in sudden death.

Methadone - Handling

How should I handle Methadone safely?

Methadone - Storage

How should I store Methadone ?

;#Keep away from children;#Keep in a cool, dry place, away from direct sunlight;#Store at room temperature;#

How should I dispose of Methadone safely?

Methadone - Additional Information

Inform your doctor or pharmacist if you are currently taking or intend to start any other medicines, supplements or herbal products.

What happens when you suddenly stop this medicine?

Do not stop taking Methadone without talking to your doctor. Stopping Methadone suddenly after taking it for a period of time may lead to possible withdrawal signs and symptoms such as sweating, chills, muscle pain, dilated pupils, irritability and insomnia. Your doctor may want to gradually reduce the amount of Methadone you are taking before stopping it completely. This is to lessen the chance of developing these withdrawal symptoms.

Methadone is a Controlled Drug in Singapore. Please DO NOT share the medicine with others.​

  • Updated on 10/2/2017 12:00:00 AM
  • Article contributed by Pharmacy Department KK Women's and Children's Hospital
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth


Find Your Medicines